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BIOLOGY: RESPIRATORY SYSTEM

from Femosky110 on 06/11/2020 12:07 PM

The Respiratory System and Gas Exchange
Cellular respiration is the breakdown of organic molecules to form ATP. Enough supply of oxygen is needed for the aerobic respiratory machinery of Kreb's Cycle and the Electron Transport System to effectively translate stored organic energy into energy rapt in ATP.

 

Carbon dioxide is as well manufactured through the metabolism of the cell and ought to be expelled from the cell. There ought to be an exchange of gases: carbon dioxide departing from the cell, oxygen entering the cell.

Animals possess organ systems concerned with the facilitation of this exchange in addition to the transport of gases to and from exchange areas.

Bodies and Respiration
Single-celled organisms substitute gases unswervingly across their cell membrane. Nevertheless, the slow rate of diffusion of oxygen as compared to carbon dioxide put a limit to the size of single-celled organisms.

All simple animals that do not possess specialized exchange surfaces possess flattened, tubular, or thin shaped body structures, which are the main effective one for exchange of gases. Nevertheless, these uncomplicated animals are quite small in size.

Large animals cannot preserve gas exchange by diffusion across their outer surface. They developed a selection of respiratory surfaces that all enlarge the surface area for exchange, thereby permitting giving room for broader bodies.

A respiratory surface is enveloped with thin, soggy epithelial cells that permit oxygen and carbon dioxide to be exchanged. Those gases can only pass through the cell membranes when they are melted in water or an aqueous solution; this means that all respiratory surfaces ought to be moist.

Methods of Respiration
Single-celled organisms exchange gases straightforwardly crosswise their cell membrane. Sponges and jellyfish for example do not have special organs for gas exchange and they obtain gases directly from the nearby water.

Flatworms and annelids make use of use their outer surfaces for gaseous exchange. Arthropods, annelids, and fish make use of gills; terrestrial vertebrates make use of internal lungs.

The Body Surface respiration known as cutaneous respiration
Flatworms and annelids make use of their outer surfaces for gaseous exchange. Earthworms possess a series of thin-walled blood vessels referred to as capillaries. Gas exchange takes place at capillaries located all through the body in addition to those in the respiratory surface.

Gills
Gills to a great extent increase the surface area for exchange of gases. They are present in a lot of animal groups in addition to the arthropods which includes a lot of some terrestrial crustaceans, annelids, fish, and amphibians.

Gills characteristically are complicated outgrowths enclosing blood vessels covered by a thin epithelial layer. In general, gills are organized into a series of plates and may be inside the body like in the crabs and fish or outside the body like in amphibians.

Gills are highly efficacious at eliminating oxygen from water: there is just 1/20 the quantity of oxygen available in water as in an identical volume of air. Water passes through the gills through one direction whereas blood passes in the opposite direction via gill capillaries. This countercurrent movement maximizes the transfer of oxygen.

Tracheal Systems
A lot of terrestrial animals posses their respiratory surfaces in the interior part of the body and linked to the outside by a group of tubes. Tracheae are these tubes that transmit air straightforwardly to cells for gas exchange.

Spiracles are apertures at the body surface that show the way to tracheae that branch into lesser tubes referred to as tracheoles. The tubes divide repetitively in order to let excessively fine tubules, tracheoles, get to the individual cells or undersized groups of cells inside the body.

The tracheae will not perform well in animals whose body is longer than 5 cm.

Lungs
Lungs are internal growths of the body wall that link to the exterior by a group of tubes and small openings.

Lung breathing was likely discovered and developed about 400 million years ago. Lungs are not only found in vertebrates, it is as well found in a few types of terrestrial snails possess gaseous exchange structures like those obtained in frogs.

Arthropods have open circulatory systems with an outstanding heart in receipt of blood from the hemocoel and pumping it into vessels for circulation to the body.

Depending on the sort of respiratory organ, the arthropod has, the circulatory system and may or may not be essential movement of oxygen to the body tissues. Those animals that do not necessarily need the blood for the circulation of respiratory gases like insects may not possess a respiratory pigment.

Respiration in invertebrate
Respiratory System Principles
1. The transportation of an oxygen-containing medium so it comes in contact with a moist membrane overlying blood vessels.

2. Diffusion of oxygen from the oxygen containing medium into the blood.

3. The transportation of oxygen to the tissues and cells of the body.

4. Diffusion of oxygen from the blood into the cells.

5. Carbon dioxide traces a path opposite to that of oxygen.

biology
The Human Respiratory System
The Pathway of the human respiratory system involve the following:

• Air is taken through the nostrils

• It then travels via the nasopharynx,

• To the oral pharynx

• via the glottis

• into the trachea and

• into the right and left bronchi, which divides and re-branches into

• bronchioles, each of which ends in a cluster of

• alveoli

It is just in the alveoli of the lung that the actual gas exchange occurs. There are a few 300 million alveoli in two adult lungs. These makes available a surface area of a few 160 m2 nearly equal to the singles area of a tennis court and 80 times the area of our skin!

Breathing
In mammals, the diaphragm splits the body cavity into the

• abdominal cavity, which possesses the viscera like the stomach and intestines and the

• thoracic cavity, which has the heart and lungs.

The inner surface of the thoracic cavity and the outer surface of the lungs are lined with pleural membranes which adhere to each other. If air is introduced between them, the adhesion is broken and the natural elasticity of the lung causes it to collapse.

This can occur from trauma. And it is sometimes induced deliberately to allow the lung to rest. In either case, re-inflation takes place as the air is slowly absorbed by the tissues.

Because of this bond, any act that increases the volume of the thoracic cavity makes the lungs to expand, making air to rush into them from the surrounding.

During the process of inspiration or inhalation,

The external intercostal muscles contract, raising the ribs up and out.

The diaphragm contracts, pulling it down.

During the process of expiration or inhalation, these processes are repeated and the normal elasticity of the lungs brings them back to their standard volume. At rest, we breathe in air 15–18 times every minute exchanging roughly 500 ml of air.

In more strenuous expiration,

The inside intercostal muscles pull the ribs down and inward

The wall of the abdomen contracts causing the stomach and liver to move upward.

Under these conditions, a standard adult male can flush his lungs with roughly 4 liters of air at every breath. This is known as the vital capacity. Even with greatest expiration, roughly 1200 ml of residual air remain.

Protozoan, porifera and coelenterate do their gaseous exchange oxygen and carbondioxide, through their body surface.

Platyhelminthes and nemahelminthes exhibit anaerobic respiration. Energy (ATP) is manufactured by glycolysis. Glycogen is further sub-divided into unstable fatty acid, CO 2 and energy. CO 2 is then expelled via body surface.

ANNELIDA: In annelid, respiratory organ is absent. Gaseous exchange occurs via the skin (cutaneous respiration), gills (branchial respiration), parapodia. Parapodium is extremely involved in (polychaetae) this process.

Every one of the parapodia possesses a capillary network and is highly supplied with blood. Body wall dorso-ventrally is made up of blood capillaries.

Haemocoelomic fluid blood gets their oxygen via the network. Respiratory pigment haemoglobin boosts the intake of oxygen by haemocoelomic fluid.

There is no specialized structure in Hirudinae and oligochaetae for exchange of gases but they do by cutaneous respiration.

Arthropoda
Aquatic arthropods characteristically possess gills for respiration apart from some exceptionally small species which have no special respiratory structures. Terrestrial arthropods make use of many different respiratory organs; the most exclusive one is the tracheal system.

There are two types of respiration in arthropods. They are Aquatic respiration and Aerial respiration.

Aquatic respiration: This type of respiration makes use of the dissolved oxygen. Aquatic respiration occurs in the following manner:

Gills are fragile feather-like development of the thoracic appendages like in the palaemon (prawn) and penaeus (scorpion), crab and tracheal gills are present in mayfly, damselfly and stonefly. Larvae have gills (blood gills and book gills) and crustacean via their body surface. Gills are extremely vascularised.

Aerial respiration: makes use of the oxygen from the air. This type of respiration is obtained in terrestrial arthropods. The respiratory organs are listed below:

a. Tracheal system ---- mainly found insects, centipedes , millipedes and a lot of arachnids.

b. Book lung ----- is found scorpion. (Extemely vascularised chamber)

c. simple lung ----- is found in terrestrial coconut crab

d. Air tube ----- This is found in terrestrial crustacean.

Summary of respiration in invertebrate
1. Express diffusion of gases to lung, gill and dermal papulae.

2. Absence of respiratory organ in lower ones but higher has composite structure for respiration

3. Express assimilation of o2 but in higher o2 rapt into coelomic fluid then transported to the assorted tissue.

4. Aquatic take dissolved o2 but higher ones either dissolved o2 or o2 expressively from air.

5. Those that possess single respiratory organ are higher than one respiratory organ

The adaptive significance of the variation in the structure of the respiratory organ of organisms living in terrestrial and those in aquatic environments

A surface that takes in oxygen ought to be kept moist. This is not an issue for aquatic organisms since they are covered with water. But terrestrial organisms would lose a huge amount of water to the dry air through the process of evaporation from the respiratory surfaces.

Therefore the majority of terrestrial animals possess their respiratory surfaces inside the body to reduce the loss of water by evaporation.

Hard exoskeleton system (arthropods) and scale in reptile are two good examples that illustrate this minimal loss of water.

BIOLOGY: HOMEOSTASIS

from Femosky110 on 06/11/2020 12:06 PM

Homeostasis
Homeostasis, which is as well spelt as homoeostasis or homœostasis is the property of a system in which variables are synchronized in order to let the internal conditions stay stable and comparatively constant.

 

Examples of homeostasis include the regulation of body temperature and the maintenance of the balance between acidity and alkalinity (pH). It is a process that maintains the constancy of the human body's internal environment in reply to changes in exterior conditions.

Every living organism maintains a balance between multifaceted set of interrelating metabolic chemical reactions. From the simplest unicellular organisms to the most composite plants and animals, interior processes function to maintain the conditions within fixed limits to permit these reactions to ensue.

Homeostatic processes act at all the five level of organization of life- the cell, the tissue, and the organ, in addition to the whole organism.

The major Homeostatic processes comprise the following:
1. Warm-blooded or endothermic animals for example mammals and birds sustain a steady body temperature, while ectodermic animals roughly every other organisms show evidence of broad body temperature variation.

The benefit of temperature regulation is that it permits an organism to function efficiently in a broad range of environmental conditions. For example, ectoderms have a propensity to turn sluggish at low temperatures, while an ectoderm that is with them at the same place tends to be completely active.

That thermal firmness arrives at a price, given that an automatic regulation system needs extra energy.

If the temperature increases, the body loses heat through sweating or gasping, through the latent heat of evaporation. If the temperature falls, it is offset by amplified metabolic action, by quivering, and in animals that have fur or feather by making thicker the coat.

2. Regulation of the pH of the blood at 7.365. pH is a measure of alkalinity and acidity of a medium and in this case the blood.

3. Another substance that is being regulated by animals is their blood glucose concentration. Mammals regulate their blood glucose with insulin and glucagon. The human body maintains constant glucose levels the majority of times during the day even after an individual observed a 24-hour fast.

Even during long periods of fasting, glucose levels are reduced only very to some extent.

Insulin, secreted by the beta cells of the pancreas, efficiently transports glucose to the cells of the body by initiating those cells to reserve more of the glucose for their own utilization.

If the glucose level inside the cells is high, the cells will convert it to the insoluble glycogen to thwart the soluble glucose from meddling with cellular metabolism. Eventually this lowers blood glucose levels, and insulin assists to avert hyperglycemia.

When insulin is lacking or cells become resistant to insulin, it leads to a condition known as diabetes occurs. Glucagon, secreted by the alpha cells of the pancreas, persuades cells to break down accumulated glycogen or convert non-carbohydrate carbon sources to glucose through the process known as gluconeogenesis, thereby averting hypoglycemia.

4. The kidneys are used to expel excess water and ions from the blood. These are afterward removed from the body in form of urine. The kidneys carry out a very important role in homeostatic regulation in mammals, expelling surplus water, salt, and urea from the blood.

5. If the water content of the blood and lymph fluid falls, it is reinstated at first by extracting water from the cells. The throat and mouth turn dry, so that the symptoms of thirst stimulate the animal to drink.

6. If the oxygen level of the blood falls, or the carbon-dioxide concentration rises, blood flow is boosted by further forceful heart action and the speed and depth of breathing as well rises.

7. Sleep timing depends on a balance between homeostatic sleep tendency, the requirement of sleep as a function of the quantity of time gone ever since the last sufficient sleep experience, and circadian rhythms that decide the perfect timing of a properly planned and curative sleep experience.

The homeostatic Control mechanisms
All homeostatic control mechanisms have a minimum of three mutually dependent constituents for the variable being regulated: The receptor is the sensing element that watches and reacts to changes in the environment.

When the receptor notices a stimulus, it gives out information to a "control center", the element that sets the range at which a variable is preserved. The control center establishes a suitable response to the stimulus.

The control center subsequently sends signals to an effector, which may be muscles, organs, or other body structures that collect signals from the control center.

After collecting the signal, a alteration is to made to annul the effect through the process of negative feedback mechanism.

Negative feedback mechanisms
Negative feedback mechanisms involve the reduction of the output or activity of any organ or system back to its standard level of functioning. A first-rate example of this is the regulation of blood pressure.

Blood vessels can detect resistance of blood flow over the walls when blood pressure rises. The blood vessels operate as the receptors and they convey this message to the brain.

The brain subsequently sends a message to the heart and blood vessels, both of which are the effectors. The heart rate would reduce as the blood vessels' diameter increases.

The process is known as vasodilation. This alteration would make the blood pressure to return to its standard level. The reverse would take place when blood pressure goes downs, and would lead to vasoconstriction.

Another significant instance is when the body is deprived of food. The body would at that point rearrange the metabolic set to a level that is less than regular value. This would permit the body to go on functioning, at a slower rate, although the body is suffering from starvation.

This is why people who are abstaining from intake of food as a means of weight loss would be able to lose some weight at the beginning but difficult as time goes on. This is because the body has readjusted itself to a lesser metabolic set-point to give the body the opportunity to live with its small energy supply.

Exercise can alter this effect by boosting the metabolic requirement.

Homeostatic imbalance
A lot of diseases involve a disturbance of homeostasis.

As the organism ages, the efficiency in its control systems becomes reduced. The inefficiencies slowly result in an unbalanced internal environment that boosts the risk of illness and results to the physical alterations connected with aging.

Certain homeostatic imbalances, like high central temperature, an elevated concentration of salt in the blood, or little concentration of oxygen, can produce homeostatic emotions like warmth, thirst, or breathlessness, which trigger off behavior meant to restore homeostasis like pulling off a sweater, drinking or slowing down.

All living organisms have perfect environmental conditions for survival and reproduction. Animals possess an interior environment together with the exterior environment they are residing in.

If their interior environment deviates too much from that ideal environmental conditions, they may witness reduction of function or they may even die. Homoeostasis is the custom-made ability of an organism to normalize its interior environment to handle and deal with alterations in the outside environment.

Animals are classified into two distinct categories with regards to the regulation of their internal environment or homeostasis. These two categories of animals are: conformers and regulators.

Conformers, or ectotherms, do not have the ability to maintain their internal environment when confronted with harsh and non conducive external environmental conditions.

For that reason, they are compelled to at all time look for favorable environmental conditions and exhibits behaviors intended to work against the environmental face up to. An example of a conformer is a lizard, which will lie around in the sun to add to its internal temperature or look for shade to reduce it.

The kidney and their functions
The human kidneys are two bean-shaped organs, each nearly the size of a fist. They are to be found just below the rib cage, one on either side of the spine. Every day, the two kidneys sort out approximately 120 to 150 quarts of blood to manufacture about 1 to 2 quarts of urine made up of wastes and additional fluid.

The urine passes from the kidneys to the bladder via two slender tubes of muscle known as ureters, one on either side of the bladder. The bladder stocks up urine.

The muscles of the bladder wall hang about relaxed while the bladder gets filled with urine. As the bladder fills to capacity, signals transferred to the brain signal the individual to set out to go to the toilet soon.

When the bladder is emptied, urine passes out of the body via a tube known as the urethra, to be found at the bottom of the bladder. In men the urethra is elongated, while in women it is small.

The diagram of human body showing the location of the urinary tract

biology
Why the kidneys are very essential in human body
The kidneys are very essential to the human body because they carry ut the functions of excretion and osmo-regulation. This means they function to ensure that the composition, or makeup, of the blood remains stable and unchangeable which allows the body function optimally.

The functions of the kidney are listed below:

To put a stop to the upsurge of wastes and additional fluid in the body

To maintain the levels of electrolytes like sodium, potassium, and phosphate and keep them stable.

To produce hormones that assist to:

standardize the blood pressure

produce the red blood cells

makes bones to remain rigid and strong

The mode of operation of the human Kidney
The kidney is not a single large filter. Each one of the kidneys is composed of roughly one million filtering units known as nephrons. Every one of the nephrons filters a little amount of blood. Each nephron contains a filter, known as the glomerulus, and a tubule.

The nephrons function through a two-step process. The glomerulus allows fluid and waste products to travel through it; but on the other hand, it inhibits the passage of blood cells and large molecules, mainly proteins through it.

The filtered fluid after that travels through the tubule which returns required minerals back to the bloodstream and eliminates wastes. The end product of the filtration results in what is known as urine.

biology
The structure of kidney nephron
In summary; Points to commit to memory

• Every day, the two kidneys sift nearly 120 to 150 quarts of blood to yield roughly 1 to 2 quarts of urine. The urine is made up of wastes and additional fluid.

• The kidneys are significant due to the fact that they maintain the composition, or makeup of the blood constant, which allows the body to function optimally.

• Each one among the two human kidneys is composed of roughly a million filtering units known as nephrons. The nephron includes a filter, referred to as the glomerulus, and a tubule.

• The nephrons function via a two-step process. The glomerulus allows fluid and waste products to pass through it; while on the other hand, it inhibits the movement of blood cells and large molecules, more often than not proteins, moving though them.

The filtered fluid subsequently passes through the kidney tubule or nephron, which returns the required minerals back to the bloodstream and eliminates wastes.

BIOLOGY: EXCRETORY SYSTEM

from Femosky110 on 06/11/2020 12:04 PM

The excretory system
The excretory system is a reflexive biological system that expels excess, needless materials from an organism, so as to help maintain homeostasis inside the organism and avert damage to the body.

 

It has the responsibility of eliminating the waste products of metabolism in addition to other liquid and gaseous wastes, like the urine and as a constituent of sweat and exhalation.

Since the majority of healthy functioning organs manufacture metabolic and other wastes, the whole organism relies on the function of the system; nevertheless, just the organs specially for the excretion process are taken as part of the excretory system.

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Parts of the excretory system and their function

1. Kidneys
The kidneys are bean shaped organs which are located in every one of the two sides of the Vertebral column in the abdominal cavity. Humans possess two kidneys and every one of them is supplied with blood from the renal artery.

Kidney expels the nitrogenous wastes from the blood like the urea and salts and excess water are as well expelled from the blood and excreted in the form of urine. This is made possible by the help of millions of Nephrons available in the kidney.

The filtrated blood is taken away from the kidneys by the renal vein or kidney vein. The urine from the kidney is gathered by the Ureter or excretory tubes, one among each one of the kidneys, and is taken to the Urinary bladder. Urinary bladder gathers and stores the urine till they are urinated.

The urine gathered in the bladder is excreted into the outside environment from the body via an opening known as the Urethra.

biology
The kidney's basic role is to remove waste from the bloodstream through urine production. They carry out many homeostatic functions like -

1. Maintaining the volume of extracellular fluid

2. Maintaining ionic balance in extracellular fluid

3. Maintaining the pH and osmotic concentration of the extracellular fluid.

4. Excreting toxic metabolic by-products like urea, ammonia, and uric acid.

The kidney does this through the 1 million nephrons contained in every kidney, these nephrons function as filters within the kidneys. The kidneys filter required materials and waste, the required materials pass back into the bloodstream, and un-required materials turn into urine and is eliminated.

In a few cases, excessive wastes turn into crystals as kidney stones. They grow and can turn into an aching pain that may need surgery or ultrasound treatments. A few stones are minute enough to be expelled via the urethra.

Liver
The liver detoxifies and breaks down chemicals, poisons and other toxins that get into the body. For instance, the liver transforms ammonia which is poisonous into urea which is subsequently filtered by the kidney into urine.

The liver as well manufactures bile, and the body makes use of bile to breakdown fats into utilizable fats and unusable waste.

Bile
After bile is manufactured in the liver, it is stored in the gall bladder. It is afterwards secreted inside the small intestine where it assists to break down ethanol, fats and other acidic wastes that include ammonia, into less harmful substances.

Large intestine
The large intestine gathers waste from all through the body. It extracts all the remaining utilizable water and subsequently eliminates solid waste. At approximately 10 feet long, it moves the wastes via the tubes to be excreted.

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Skin
The Skin excretes sweat via the sweat glands all through the body. This assists to expel additional wastes, like excess urine. Moreover, the sweat assisted by salt, escapes and helps to maintain the coolness of the body when the body gets warm.

Sweat glands in the skin secrete a fluid waste known as sweat or perspiration; although, its fundamental roles are temperature control and pheromone release. Therefore, its function as a component of the excretory system is negligible. Sweating as well regulates the level of salt in the body.

biology
Eccrine
Like sweat glands, eccrine glands allow excess water to escape from the body. A lot of eccerine glands are situated largely on the forehead, the bottoms of the feet, and the palms, even though the glands are all over the place in the body. They assist the body to retain its temperature control.

Lungs
One of the major roles played by the lungs is to diffuse gaseous wastes, like carbon dioxide, from the bloodstream as a typical part of respiration.

Ureter
The ureters are muscular tubes that thrust urine from the kidneys to the urinary bladder. In the human adult, the ureters are typically 25–30 cm (10–12 in) long. In humans, the ureters come up from the renal pelvis on the medial facet of every kidney prior to sliding towards the bladder on the front of the psoas key muscle.

The ureters pass over the pelvic brim next to the bifurcation of the iliac arteries. This "pelviureteric junction" is a widespread site that usually feels the impact of the kidney stones. Another site that feels the same impact is the uteterovesical valve.

The ureters dash posteriorly on the sideways walls of the pelvis. They after that bend anterior medially to go through the bladder via the back, at the vesicoureteric junction, passing within the wall of the bladder for some centimeters.

The backflow of urine is prohibited by valves referred as ureterovesical valves. In the female, the ureters pass via the mesometrium on the way to the bladder.

Urinary bladder
The urinary bladder is the organ that collects waste excreted by the kidneys prior to when they are eliminated via urination. It is a bare muscular, and distensible or elastic organ, and settles on the pelvic floor. Urine moves into the bladder via the ureters and to the exterior through the urethra.

Embryologically, the bladder is gotten from the urogenital sinus, and it is at first uninterrupted and with the allantois. In human males, the bottom of the bladder lies in between the rectum and the pubic symphysis.

It is superior to the prostate, and estranged from the rectum by the rectovesical dig. In females, the bladder lies inferior to the uterus and in front of the vagina. It is alienated from the uterus by the vesicouterine dig. In infants and young children, the urinary bladder is in the abdomen even when unfilled.

Urethra
In anatomy, the urethra is a tube which connects the urinary bladder to the exterior part of the body. In humans, the urethra has an excretory function both in male and in female.

Urine Formation
Inside the kidney, blood at first moves via the afferent artery to the capillary formation known as glomerulus and is gathered in the Bowman's capsule -located in the liver, which separates the blood from its contents—principally food and wastes.

After the filtration process, the blood subsequently goes back to gather the food nutrients it requires, while the wastes moves into the collecting duct, to the renal pelvis, and to the ureter, and are then after that excreted out of the body through the urinary bladder.

General features of excretory structures and functions
The physiological process by which organisms dispose of its nitrogenous by-products is known as excretion.

The meaning of excretion is for the most part simply understood in the perspective of vertebrate structure. The animal ingests food (ingestion). In the stomach and intestine a few of the food is converted into soluble products (digestion) that are assimilated into the body (assimilation).

In the body these soluble products experience additional chemical change (metabolism); a few are used by the body for growth, but the majority makes available energy for a variety of activities of the body.

Metabolism involves the intake of oxygen and the removal of carbon dioxide in the lungs (respiration).

Above and beyond carbon dioxide, compounds of nitrogen occur from metabolism and are done away with, mainly by the kidney, in the urine (excretion). Food not digested is expelled via the anus (defecation).

Products of excretion
Although every type of organism takes in a few materials and get rid of other, excretion is strictly a process seen in animals alone. For the purposes of this tutorial excretion will be taken to mean the removal of nitrogenous by-products and the regulation of the constituent of the body fluids.

The most important excretory product that occurs naturally in the animal body is ammonia, obtained roughly completely from the proteins of the ingested food. In the process of digestion proteins are converted into their component amino acids.

Some of the amino-acid pool is subsequently utilized by the animal to manufacture its own proteins, but a lot of it is utilized as a source of energy to compel other imperative processes.

The first step in the mobilization of amino acids for energy production is deamination, which means the removal of ammonia from the amino-acid molecule. The remaining is oxidized to carbon dioxide and water, with the associated manufacturing of the energy-rich molecules of adenosine triphosphate ATP.

The fact that excess levels of ammonia are extremely harmful to the majority of animals, they ought to be efficiently expelled. Minute aquatic animals do not have the same problem because ammonia swiftly diffuses, as a result of its high solubility in water into the surrounding water surfaces.

However in terrestrial animals, and in a few outsized aquatic animals, ammonia is transformed into varieties of less harmful compounds through the process known as detoxication.

In mammals, human being inclusive, it is detoxified to urea, which is taken to be produced through the condensation of a molecule of carbon dioxide with two molecules of ammonia.

Excretory mechanisms
biology
Vital information on the mechanism of Excretory System in Man

The human excretory system is made up of two kidneys that are bean shaped. The presence of two kidneys in human body is of a very big significance. When one kidney fails, the other can still perform the function of excretion.

The left kidney is situated a little higher than the right kidney. The kidneys are solid, reddish-brown, roughly 10 cm long organs which is situated in the abdominal cavity, one on each side of the vertebral column.

Every human kidney weighs about 150 g. The outer surface of the kidney is convex in shape while the interior is concave. There is a concave hollow known as hilus through which the arteries and veins pass into and leave the kidney.

Kidneys play a crucial role important role in regulating the composition of blood through the process known as osmo regulation.

Interesting points about excretion through kidney
• Roughly 130 ml of filtrate are produced every minute in the glomeruli of the two kidneys of man.

• Roughly 99% of the water of the filtrate is reabsorbed as it moves down the nephron.

• Body salts excreted in human urine may be about 2.2% and urea 6% of the volume of urine.

• The yellow colour of urine is as a result of a pigment called urochrome.

• Roughly1600 ml urine is excreted by an adult in 24 hours. A nephron is a 5-cm extended tubule.

• Urination is known as micturition. This is a reflex action (quick action) that is under the control of the spinal cord.

BIOLOGY: TISSUES SYSTEM

from Femosky110 on 06/11/2020 12:02 PM

Tissues and supporting system:
In biology, tissue is a cellular organizational level that is midway between cells and a complete multicellular organism. A tissue is a collection of similar cells from the identical origin that perform a particular function.

 

Organs in turn are obtained by a collection of several tissues. The study of tissue is referred to as histology and when tissue is studied with respect to disease, it is known as histopathology.

The standard tools for studying tissues are the paraffin block to which tissue is fixed and subsequently segmented, the histological stain, and the optical microscope.

In the past few decades, advancements in electron microscopy, immunofluorescence, and the utilization of frozen tissue sections have improved the feature that can be seen in tissues. With these tools, the standard looks of tissues can be studied in health and disease facilitates substantial enhancement of clinical diagnosis and prognosis.

Animal Tissue:
Animal tissues can be classified into four fundamental types: connective tissue, muscular tissue, nervous tissue, and epithelial tissue.

Several tissue types make up organs and body structures. Although all animals can by and large be well thought-out to have the four types of tissues, the appearance of these tissues can vary depending on the nature and form of the organism.

For instance, the source of the cells containing a specific type of tissue may vary in terms of development for a variety of animal classification.

The epithelium in all animals is the derivative of the ectoderm and endoderm with a little input from the mesoderm, structuring the endothelium, a specific kind of epithelium that comprises the vasculature.

On the contrary, a true epithelial tissue is only available in one layer of cells knitted together through occluding junctions referred to as tight junctions, to form a selectively permeable wall.

This tissue covers every surface of the organism that is exposed to the outside environment like you would obtain in the skin, the airways, and the digestive tract. Its sole function is for protection, secretion, and absorption. It is alienated from the rest of the tissues below by a lamina on the base.

Connective tissue
Connective tissues are composed of fibers. They are composed of cells divided by non-living substance referred to as an extracellular matrix. Connective tissue makes available shapes to organs and keeps them in place.

The blood and bone are examples of connective tissue. Just as you would deduce from the name, they support and connect other tissues. In contrast to the epithelial tissue, connective tissue characteristically has cells spread all through an extracellular matrix.

Muscular tissue
Muscle cells come together and form the energetic contractile tissue of the body referred to as muscle tissue or muscular tissue. Muscle tissue function is to generate force and cause movement, either locomotion or the movement of internal organs.

Muscle tissue is classified into three different categories: visceral or smooth muscle, which is created in the inner linings of organs; skeletal muscle, in which is found attached to bone making possible gross movement; and cardiac muscle which is seen in the heart, and which enables it to contract and pump blood all through the organism.

The muscular tissue is the most elongated group of cells in the human body.

Nervous tissue
The nervous or neural tissue is made up of all cells that made up the central nervous system and peripheral nervous system.

In the central nervous system, neural tissue come together to give rise to the brain and spinal cord while in the peripheral nervous system it forms the cranial nerves and spinal nerves in addition to the motor neurons.

Epithelial tissue
The epithelial tissues are made up of cells that envelop the organ surfaces like the surface of the skin, the airways, the reproductive tract, and the inner coating of the digestive tract.

biology
The cells that made up the epithelial layer are connected through semi-permeable, tight junctions; and so, this tissue acts as a boundary between the outside environment and the organ it covers. Apart from this protective function, epithelial tissue may as well be focused to perform secretion and absorptive function.

Epithelial tissue shields organisms from microorganisms, injury, and water loss. The functions of the epithelia tissue is listed below:

• the epithelia cell of the body surface form the outer layer of skin.

• Within the body surface, epithelial cells forms lining of mouth and alimentary canal and guard these organs.

• epithelial tissues assist in the absorption of water and nutrients.

• epithelial tissues assist in the removal of waste product.

Types of epithelia tissue
The various types of epithelial tissues are listed below:

• Squamous epithelium,

• Cuboidal epithelium,

• Columnar epithelium,

• Glandular epithelium,

• Ciliated epithelium.

Skeletal Tissue
The skeletal tissue is of three types. The three types of skeleton or skeletal tissue are hydrostatic skeleton, endoskeleton and exoskeleton. Hydrostatic skeleton is seen in cold-blooded animals in addition to invertebrates. Human beings have endoskeleton. Exoskeleton is available in insects.

Hydrostatic Skeleton
It is seen in soft-bodied and cold-blooded animals. This skeleton has a coelom, which is a fluid-filled cavity. The coelom is covered up by muscles and the stiffness initiated by the fluid and the muscles provide the supporting construction for the organisms.

The fluid pressure in addition to the motion of the supporting muscles assists the organisms to modify shape and move. Invertebrates, the greater part of the earth's living organisms are present in an enormous number of habitats.

They could be seen in the deepest part of the oceans to the thickest forests. These invertebrates possess a hydrostatic skeleton system that assists them to flourish in a different number of landscapes.

Echinoderms, cnidarians, annelids, nematodes and some other organisms use the hydrostatic skeleton for movement. The Earthworm which is an annelid has no bone. Through hydrostatic skeleton it makes hole through the ground. Examples of echinoderms are the star fish and the sea urchin. The Jelly fish is a cnidarians.

Endoskeleton
The simplest explanation for endoskeleton is that it is the skeleton located in the body. It forms the frame work for the animal. The tissues and muscles are produced around the skeletal system and the well-developed forces are passed on to this skeleton.

The Endoskeleton supports the animal constitution. It is made up of mineralized tissues. In Phylum Chordata, Porifera and Echinodermata endoskeleton is present.

Endoskeleton is created in the sub-class Coleoidae. The animals that belong to Phylum Chordata are all vertebrates in addition to human beings. Phylum Porifera are sponge-like animals and is made up of about 5000 species.

Its skeleton is a complex of organic fibres, a pedestal of calcite and aragonite and spicules of silica. Here the endoskeleton is for maintainance. Phylum Echinodermata is made up of a variety of symmetrical marine animals such as the star fish, sea urchins and so on. It has an endoskeleton composed of calcium and is enclosed with spines.

Echinoderms have endoskeleton because they have an interior calcareous skeleton. But for motion, it makes use of the tentacles which are comparable to a hydrostatic skeleton.

The endoskeleton in chordates and echinoderms are formed from mesodermal tissue and it is taken to be the true endoskeleton. In Coleoidae, the exoskeleton has evolved into the inner structure. Example is cuttle fish.

Exoskeleton
Exoskeletons are skeletons that exist outside the body. It forms a shielding covering for the animals. It supports and also protects the animals. All crustaceans possess exoskeleton. Crabs, spiders, lobsters, insects are all crustaceans.

Animals with exoskeleton are typically small. This is due to the fact that big animals could not be sustained by exoskeleton and need bones to hold them up. Animals with exoskeleton possess a head and abdomen and in a number of cases, a thorax.

The exoskeleton is supple and thin at the joints where it ought to bend. The outsized exoskeletons are referred to as shells. Tortoise is an animal that has a shell and endoskeleton.

The simplest type of skeleton is the hydrostatic skeleton obtained in a lot of cold-blooded organisms and soft-bodied animals. The pressure of the fluid and action of the adjoining muscles are used to alter an organism's figure and generate movement. This fluid filled cavity is referred to as the coelom.

The human Skeletal System
biology
The supporting tissues of animals which frequently serve as a protection for the body or parts of it and play a crucial role in the animal's physiology is known as skeleton.

Skeletons can be divided into two major types in relation to the comparative location of the skeletal tissues. When these tissues are situated outside the soft parts, the animal is said to possess an exoskeleton.

If they take place deep inside the body, they constitute an endoskeleton. All vertebrate animals have an endoskeleton, but the majority as well has components that are exoskeletal in origin. Invertebrate skeletons, nonetheless, demonstrate far more disparity in position, morphology, and materials used to assemble them.

The vertebrate endoskeleton is typically made up of bone and cartilage; with the exception of a few fishes that possesses skeletons that do not have bone.

In addition to an endoskeleton, a lot of species have distinct exoskeletal structures composed of bone or horny materials. This dermal skeleton makes available support and safeguard at the body surface.

A lot of structural components constitute the human skeleton, which includes the collagen, three diverse types of cartilage (hyaline, fibrocartilage, and elastic, as well as a lot of bone types-woven, lamellar, trabecular, and plexiform.

The vertebrate skeleton is made up of the axial skeleton –the skull, vertebral column, and related structures and the appendicular skeleton which consists of limbs or appendages. The essential plan for vertebrates is comparable, though great variations take place in relation to functional demands placed on the skeleton.

Axial skeleton
The axial skeleton provides support for the organs of the head, neck, and torso and as well offers them protection. In humans, the axial skeleton is made up of the skull, ear ossicles, hyoid bone, vertebral column, and rib cage.

Skull
The adult human skull is made up of eight bones which make up the cranium, or brain box, and 13 facial bones that sustain the eyes, nose, and jaws. There are as well three small, paired ear ossicles—the malleus, incus, and stapes—inside a hollow in the temporal bone.

The totality of 27 bones represents a huge drop in skull elements all through the course of vertebrate advancement. The three components of the skull are the neurocranium, dermatocranium, and visceral cranium.

The brain and certain sense organs are sheltered by the neurocranium.

Every vertebrate neurocrania grow in the same way, beginning as ethmoid and basal cartilages beneath the brain, and as capsules partially encircling the tissues that finally form the olfactory, otic, and optic sense organs. Additional growth manufactures cartilaginous barricades around the brain.

Vertebral column
The vertebral column is an endoskeletal segmented shaft of mesodermal derivation. It protects the spinal cord, acts as sites for muscle attachment, offers flexibility, and support, especially in land-based tetrapods where it has to maintain the weight of the body.

Hard, spool-shaped bony vertebrae exchange with tough but flexible intervertebral discs. Every typical vertebral body (centrum) has a bony neural arch extending dorsally. The spinal cord pass through these arches, and spinal nerves come out through the spaces.

BIOLOGY: CELL PROPERTIES

from Femosky110 on 06/11/2020 12:00 PM

The Properties of the Living Cell
A cell is the smallest unit of life. The cell is the beginning point for every organism. A few living things like bacteria are made up of one cell, while a complex organism like the human body is made up of trillions of cells.

 

In the multicellular animals, a group of cells makes up tissues, and a group of tissues which make up organs, which in turn make up organ systems, which also come together to make the complete animal. Without the cells we would not exist.

The cell is made up of three basic components of all cells: an outer cell membrane, an inner nuclear region, and the cytoplasm which is found in between them. Cellular biology is one aspect of biology that is hugely studied.

Cells are very significant because they carry out all of life's functions. Without cells, we would not even be able to shift a muscle, for the fact that the reactions that are required to allow it to happen would be absent.

biology
Nutrition in Plants
Classification of plants on the basis of mode of nutrition:
Plants can be divided into two groups on the basis of their mode ofXThe two groups are:

1. Autotrophic or autotrophs

2. Heterotrophic or heterotrophs

Heterotrophic nutrition is the type of nutrition obtained by digesting organic compounds. Animals, fungi, a lot of prokaryotes and protoctists which are incapable of synthesizing organic compounds for their food, feed heterotrophically. They are thus referred to as heterotrophs.

Holozoic nutrition is a form of heterotrophic nutrition which requires dependence.

Parasitic nutrition is a mode of heterotrophic nutrition where an organism lives on the body surface or inside the body of another type of organism

1. Autotrophic nutrition
Autotrophic nutrition is the type of nutrition in which organic compounds are manufactured from available inorganic raw material obtained from the environment. In autotrophic nutrition, the nutrients do not require to be broken down or digested before they are taken into the cells.

Two methods of autotrophic nutrition
On the basis of source of energy, autotrophic nutrition can be further divided into the sub-types listed below:

(I) Phototrophic nutrition

(II) Chemotrophic nutrition

I. Phototrophic nutrition:
Phototrophic nutrition is the form of autotrophic nutrition in which organic molecules are produced from uncomplicated inorganic molecules with the help of energy obtained from sunlight.

Example of phototrophic nutrition can be seen in:

a. Green Plants

b. Photosynthetic Bacteria

Phototrophic nutrition as obtained in green plants
Green plants are well-known example of phototrophic nutrition. Green plants manufacture their own food through the process of photosynthesis. The materials necessary for photosynthesis to occur are:

CO2 and H20
Carbon dioxide and water make available carbon, hydrogen and oxygen which are required for the synthesis of organic molecules.

Minerals
The minerals such as Nitrogen, Phosphorus and Sulphur and Magnesium are also essential for photosynthesis to take place.

The Chlorophyll:
The green pigments known as Chlorophyll is as well necessary for photosynthesis to take place. It is essential to absorb the energy from the sun which is the universal source of light.

The sunlight :
In the presence of sun light, the above mentioned nutrients are used to synthesize the energy rich compound known as (CHO). This process is known as photosynthesis.

Photosynthesis can be represented through the following equation:

6CO2 + 12H2O -> C6H12O6 + 6O2 + 6H2O

Phototrophic nutrition in photosynthetic bacteria
Photosynthetic bacteria are inimitable due to the fact that they are the only organisms that have the capacity to synthesize carbohydrate food in the absence of chlorophyll.

Differences between photosynthetic bacteria and green plants
Photosynthesis in bacteria differs from that of green plants. Some differences between them are

Photosynthetic bacteria normally grow in sulphide spring which usually contains H2S.

The hydrogen used in the synthesis is obtained from H2S as opposed to water - H2O in green plants.

In bacteria photosynthesis, oxygen is not liberated to the surrounding as a byproduct.

The process of bacteria photosynthesis occurs with a little release of energy.

Two types of photosynthetic bacteria:
There are two types of photosynthetic bacteria. The first group releases sulphur "S" as a bye product. This type of bacteria gets the hydrogen for the synthesis from H2S. The energy from the light divides into hydrogen ion and sulphide ion. Hydrogen reacts with CO2 to form H2O as shown in the equation below:

2H2S + CO2 -> (CH2O)n + H2O + 2S

Example of such bacteria is the Purple Sulphur Bacteria which make use of bacterio chlorophil and caretenoid as the pigments for photosynthesis.

The second group of photosynthetic bacteria is those who do not release sulphur "S" as the by-product. These bacteria make use of H2S as the donor of hydrogen but sulphur is not released as a by-product.

Examples of this type of bacteria are the purple non-sulphur bacteria and the brown non-sulphur bacteria. Both of them have "bacterio chlorphyll" as their photosynthetic pigments.

Chemotrophic nutrition:
Chemotrophic autotrophic nutrition is the type of autotrophic nutrition where organic molecules are produced from simple inorganic molecules through the use of energy obtained from the oxidation of a few inorganic substances like ammonia, nitrates, nitrites, ferrous ions, H2S and so on.

This type of nutrition is known as chemotrophic nutrition and process of manufacturing food in this manner is referred to as chemosynthesis.

Example of organism that does chemosynthesis is the bacteria like ammonia using bacteria. They obtain their energy by oxidizing Ammonia as illustrated in the equation below:

NH4+ + O2 -> 2NO2 + 2H2O + 4H+ + energy

Another type of bacteria which converts nitrites to nitrate does it through the process of chemosynthesis as shown in the equation below:

2NO2 + O2 -> 2NO3- + energy

Importance of chemosynthetic bacteria:
The chemosynthetic bacteria that act on nitrogen compounds play a crucial role in nitrogen cycle and ensure that a balance of nitrogen is sustain in the life system.

2. Hetertrophic Nutrition in Plants
Plants which are not able to manufacture their own food completely or partially and are dependent on other in order to get their organic molecules are referred to as heterotrophic plants.

Classification of heterotrophic plants
On the basis of type of organisms on which heterotrophic plants depend on for the synthesis of their organic molecules, they can be divided into the two classes below:

• Parasitc Plants Or Parasites

• Saprophytic Plants Or Saprophytes

1. PARASITES
These are heterotrophic plants that depend on living plants and animals for their nutritional requirements.

Types of parasites
Parasitic plants can be further divided into the following types.

• Obligate or total parasites.

• Facultative or partial parasites.

Total parasites are those parasites which depend on other organism entirely for their food or organic materials.

Total parasites are further classified into two:

1. Total stem parasite

2. Total root parasite

1. Total stem parasites are the category of parasitic plants that depend entirely on the stem of other plants for their food. These plants propel a structure called haustoria which is a special structure used in the absorption of nutrients in parasitic plants inside the tissue of host.

The xylem of the parasite comes in contact with the xylem of host and the phloem of the parasite to the phloem of the host. Through the xylem it draws up the water and nutrients and through the phloem, it draws up prepared organic material.

This eventually leads to the death of the host plant as a result of exhaustion. Example of such parasite is the cuscuta (amer-bail)

2. Total root parasites:

These are parasitic plants which draw up their nutritional requirements from the roots of host. Examples are:

1. Orobanche- This normally attacks the roots of the plants that belonged to the families -Cruciferae and Solanaceae.

2. Cistanche - These Parasitizes attacks the roots of Calatropis.

3. Striga – These parasites are found on the roots of sugar cane

Partial parasites
These are those parasitic plants which depend partially on other organism for their nutritional value.

Classes of partial parasitic angiosperms:
Partial parasitic angiosperms can be generally classified into

1. Partial stem parasite

2. Partial root parasite

1. Partial stem parasites
Partial stem parasites are those parasites whose their haustoria penetrate into the stem of the host and to suck their nutrition from vascular tissues of stem.

2. Partial root parasites
The example of this category of parasite although uncommon is the sandle wood tree

Saprophytes
Saprophytes are plants that depend on dead or rotten organic remains of plants or animals for their food or nutritional intake. Also plants which decompose composite dead food material into simple compounds and make use of them for their nutrition, growth and development are referred to as saprophytes.

Types of Saprophytes
Saprophytes can be sub divided into two namely:

1. Total Saprophytes

2. Partial Saprophytes

Total saprophytes
This group of saprophytes depends totally on dead organic material for their nutritional value.

Partial saprophytes
These are type of saprophytes which depend partly on dead organic matter for their nutritional value.

Examples of saprophytes
There are a few examples of Saprophytes amongst flowering plants.

1. Neothia -bird's net or orchid

2. Monotrapa- Indian Pipe

In these two cases, the roots of plant form a Mycorhizzal Association with fungal mycelium to assist them in the absorption process.

Special mode of nutrition
Carnivorous or insectivorous plants
Carnivorous or insectivorous plants are plants which have as their prey, insects and small birds. This is a special mode of nutrition in partially autotrophic and partially heterotrophic plants.

Partially autotrophic and partially heterotrophic plants are carnivorous plants which has the green pigments and can produce CHO but are not able to synthesize nitrogenous compounds and proteins.

In order to get their nitrogen requirement, carnivorous plants depend on insects, which they trap and digest through particular devices developed in them.

Cellular respiration
This is the set of the metabolic reactions and processes that occur in the cells of organisms to transform the biochemical energy from nutrients into adenosine triphosphate (ATP), and after that releases waste products.

The reactions that are required in respiration are catabolic reactions, which split large molecules into smaller ones, with the release of energy in the process where the weak "high-energy" bonds are replaced by stronger bonds in the products.

Respiration is among the main ways a cell gains helpful energy to fuel cellular activity. Cellular respiration is taken as an exothermic redox reaction. The general reaction is converted into a lot of smaller reactions when it takes place in the body, the majority of which are redox reactions themselves.

Even though in principle, cellular respiration is a combustion reaction, it obviously does not bear a resemblance to one when it takes in a living cell. This variation is due to the fact that it takes place occurs in a lot of detached steps.

While on the whole, the reaction is a combustion reaction, no particular reaction that it is composed of is a combustion reaction.

BIOLOGY: CELL AS LIVING FORM

from Femosky110 on 06/11/2020 11:58 AM

Cells as Living Unit-Forms in which living things exit
The cell is the basic unit of organization for the majority of living things. Living things can be classified as multicellular ie organisms that are made up of varieties of cells, or unicellular-organisms that are made up of only a single cell.

 

Cells are the fundamental or basic unit of life both in plants and in animal. Cell can exist as a living unit as opposed to being part of a larger or multicellular organism. Thus cell can exist in various forms. The following are forms in which living cell exists:

Group of cells that form tissue are part of a living multicellular organism and cannot survive on their own. They would normally require the functions of other cells in the body to remain alive while the groups of cells that form colonies or filament are individual organism capable of carrying out all the body processes on their own.

Their existence as a colony or as a filament is for the sake of mutual and symbiotic relationship. These free living or colonial organisms that are single celled with different modes of nutrition, locomotion and reproduction is referred to as protista.

A group of cells that perform same or similar function are joined together to make tissue. A number of tissues joined together to perform a specific function join together to make up an organ like the the heart, the stomach, or the lungs.

A lot of organ that functions together to achieve one common purpose are referred to as System- Examples the cardiovascular system, which is made up of the heart, arteries, veins, capillaries, and blood, and the respiratory system, that is made up of the lungs.

Dissimilar organ systems that provide unlike purposes for the same effect, normally described as good health, are called an organism, like the human being. Therefore cell is in the lowest level, the most widespread denominator in this pecking order of cell structure and organization.

In unicellular organisms, all the processes of life are being carried out by a single cell while in multicellular organisms, the life processes are being carried out by the five various levels of organization-cell-organ-tissue-system-organism. The human body for an example is made up of contains 11 organ systems.

Single and free-living:
Single celled organisms are organisms that are consist of only a single cell. They are as well referred to as unicellular organisms. Examples of single celled organisms are amoebas, paramecium, volvox, protozoa, spirogyra, euglena, animalcule, diatoms, prokaryotes, bacteria (or bacterium), yeast, and archaea.

Again, xenophyophores are the largest single celled organism ever found. They were discovered in October 2011 in the Mariana Trench, 6 miles under the surface of the ocean. Another big single celled organism is the syringammina fragilissim .

These single celled organisms have the tendency to reach a diameter of up to 20 centimeters. Examples of organisms that exist as a single cell and are free living are Amoeba, Paramecium, Euglena and Chlamydomas.

Many life forms are composed of a single cell. In addition to simple bacteria, there are more composite organisms, referred to as protoctists. Dissimilar to bacteria, they have composite internal structures, like nuclei which contain organized strands of genetic material known as chromosomes.

The majority of them are single-celled, but some form colonies, with every one of the cell remaining independent.

Euglena is a single-celled organism that uses flagellum for locomotion. The single-celled organism that uses cilia or hair like projections for locomotion is Paramecium. Amoeba is a single-celled organism that makes use of pseudopods to surround and engulf their food.

A single-celled organism that is made up of a colony of ciliates with some containing chlorophyll is Volvox. Euglena is a single-celled organism that has a unique feature of an eye spot. Amoeba is a single-celled organism that moves by cytoplasmic streaming. The two types of single-celled organisms that have chlorophyll are Euglena and Volvox

Amoeba: This is a single-celled predator that does not possess a definite shape. It can make a projection of parts of its cell to form a gelatinous tentacle referred to as pseudopodia.

The amoeba makes use of the pseudopodia for locomotion for touching and grabbing a prey. They live in water and are found creeping along decaying vegetation. They prey on smaller cells like bacteria.

Algae are currently classified as protoctists, even though scientists formally classified them under plant kingdom. Algae can manufacture their own food through the process of photosynthesis since they contain green chloroplasts.

Euglena and algae live in ponds. When they are placed in the dark, they lose their chloroplasts and then feed like animals. Seaweeds are good examples of popular algae. They are composed of enormous communities of algae cells.

A few protoctists obtain their food by invading other organisms and living on them as parasites. Example is the malaria parasite which first enters its human host through the bite of the Anopheles mosquito.

As soon as it gets into the human system, it multiplies inside the blood and may cause liver infection. The parasite causes a fatal disease known as malaria fever.

Slime moulds begin like amoeba-like cells that searches for food in damp habitats. Eventually, the cells combine together to form spore-producing feature.

As a colony:
Example of single celled organism that exists as a colony is Volvox. In biology, a colony refers to a number of individual organisms of similar species existing together for mutual benefit.

Examples of such benefits they could get from each other include the strength or the ability to attack a bigger prey. Some insects like ants and bees live in colonies.

Colonial organisms are organisms that live intimately together, in a colony. For instance bacteria, Volvox, Pandorina, Sponges, algae and Salps are also examples of colonial organisms. Each organism/cell in the colony can exist on its own and may or may not benefit from other cells in the colony.

In biology, a colony refers to individual organisms of the same species living closely together, more often than not for mutual benefit, like stronger defense or the capacity to assault bigger prey. A few insects like ants and honey bees live only in colonies.

A colony of single-cell organisms is referred to as a colonial organism. Colonial organisms were almost certainly the first step toward multicellular organisms through natural selection.

A bacterial colony is defined as a observable cluster of bacteria that grows on the surface of or within a solid medium, most probably cultured from a single cell.

Due to the fact that every organism inside the colony descends from a single antecedent, they are genetically the same apart from mutations that usually take place at a small frequency, in addition to a possibility for them to be contaminated.

Getting hold of that type of genetically matching organisms or pure strains can be useful in loads of cases. It can be done by dispersing bacteria on a culture plate and starting a fresh stock of bacteria from a single colony.

A biofilm is a colony of microorganisms over and over again made up of a lot of species, with properties and abilities greater than the combinations of abilities of the individual organisms.

Types of cell colonies
In the process of evolution unicellular organisms began to co-exist in three different ways:

1. A colony is a group of related living organisms that are linked to each other through their own secretions, or cytoplasmic strands, but there isn't any suitable transportation system between the cells.

Colonies are formed due to daughter cells that stay together instead of separating apart from each other after the cell division. Any member of the colony has the capability to exist on its own.

2. Symbiosis is an inter-relationship between two or more different organisms which usually benefit from the relationship.

3. Endosymbiosis is a form of symbiosis where a colony member known as a microsymbiote lives within the other. Nowadays, scientists are of the opinion that the cell organelles mitochondria are, in reality, microsymbiotres that formally lived as free living bacteria cells. Ultimately these bacteria developed into a part, or organelle, of the host cell. This type of relationship is referred to as endosymbiotic.

As a filament:
Cell can as well exist as a filament. Example of single celled organism which exists as a filament is the Spirogyra. A few organisms exist as filaments with related cells are joined end to end to form unbranched filaments.

biology
Each cell in the filament works independently from the other. These types of organisms that exist as filament are multicellular. Other examples of filamentous organisms are the Zygnema, Oscillateria and Oedogonium.

Lastly a cell can as well exist as part of a living organism both in plant and in animal. Example of cases where the cell exists as part of a living organism is cheek cell, onion root tip cells and the epidermis of fleshy leaves.

A single cell can be the smallest possible unit and has the potential to grow into an entire colony.

Multicellular organisms are made up of many cells and in the majority of cases many organs where every cell that make up the organism cannot function as a whole organism and cannot as well exist independently of other cells.

The variation between a multicellular organism and a colonial organism is that individual organisms from a colony can, if alienated, survive on their own, while cells from a multicellular life form like cells from a brain cannot. Volvox which is technically referred to as a coenobium is an example of the boundary between the two states.

If onion epidermal tissue is engrossed into a solution of calcium nitrate, cells speedily lose water by osmosis and the protoplasm of the cells shrinks.

This happens due to the fact that the calcium and nitrate ions generously leak into the cell wall and come across the selectively permeable plasma membrane.

The large vacuole in the center of the cell at first contains a dilute solution which has a much lower osmotic pressure than that of the calcium nitrate solution on the other side of the membrane. The vacuole in this manner loses water and becomes smaller.

The space between the cell membrane and the cell wall then gets bigger and the plasma membrane together with the protoplasm inside it contract to the center of the cell.

Strands of cytoplasm expand to the cell wall due to the attachment points between the cell wall and the plasma membrane. Plasmolysed cells easily die except they are transferred fast from the salt or sugar solution to water.

Comparisons of Single-celled Organisms
Euglena
• Moves by flagellum

• It is known for a unique feature—eye spot

• Some Euglena contain chlorophyll

• A few of them are commonly found in fresh water

Amoeba
• They move through cytoplasmic streaming

• They surrounds food and engulfs it with the use of pseudopods

Paramecium
• Paramecium is the most complex and specialized of the protists

• They use their hairlike projections known as cilia for movement.

biology
Volvox
• Volvox is a colony of ciliates

• A few Volvox contain chlorophyll

BIOLOGY: CELL STRUCTURE

from Femosky110 on 06/11/2020 11:55 AM

Cell Structure And Functions Of Cell Components
The cell is the basic functional and structural unit of life. Human beings are multi-cellular animals. What this means is that we humans are made of many cells of cells as opposed to unicellular organisms which are composed of only one cell. The cells in a lot of multi-cellular animals and plants are specialized.

 

This means that each of them carries out a specific function and when all the cells combine together with their functions, they can share out the processes of life. Each cell is dependent on the other and all of them function collaboratively to support the diverse processes in an organism.

The tables below show examples of some specialized animal and plant cells, together with their functions and special features.

Table illustrating the different types of animal and plant cells with their specific features and functions
Type of animal cell Function Special features
1. Red blood cells To transport oxygen round the body It has large surface area, for oxygen to pass through. The red blood cell contains haemoglobin, which reacts with oxygen to form oxyhaemaglobin
2. Nerve cells Nerve cells transports nervous impulses to various parts of the body It has a long connections at each end and has the capacity to carry electrical signals
3. Female reproductive cell also known as the egg cell The egg cell's function is to combine with the male cell, and subsequently to make food available for the new cell that was formed The egg cell is large and contains a lot of cytoplasm
Male reproductive cell which is also known as the sperm cell. The sperm cell function is to travel up and meet with egg cell for a fusion to form a zygote. The sperm cell has an elongated tail for swimming as well as a head which enables it to get attached with the female egg cell for a fusion.

Type of plant cell Function Special features
1. Root hair cell The root hair cell absorbs water and minerals from the soil. It has a large surface area
2. Leaf cell The leaf cell absorbs sunlight for the process of photosynthesis It has large surface area and lots of chloroplasts
Plant and animal cells have quite a few differences and similarities. For instance, animal cells do not have a cell wall or chloroplasts but plant cells have them. Animal cells are round and irregular in shape whereas plant cells have fixed rectangular shapes.

Comparison chart between plant and animal cell
Animal cells and plant cells
• Animal cells are more often than not irregular in shape, and plant cells normally have a regular shape.

• Cells are made up of various parts which can be easily explained through the use of diagrams as illustrated below:

biology
Both the animal cells and plant cells contain:

• Cell membrane

• Cytoplasm

• Nucleus

Plant cells in addition to possessing these features also found in animal cell has:

• Chloroplasts

• Vacuole

• Cell wall

The table below summarizes the Differences and Similarities of plant and animal cells in terms of the features they contain.

Features              Animal Cell                                                                              Plant Cell
Cell wall               Absent                                                                               Present. It is formed from cellulose and is known as cellulose                                                                                                                                    cell wall
Shape         It has a round or irregular shape                                              It has a rectangular or fixed shape
Vacuole      It contains one or more small vacuoles                                  It has one central vacuole that occupies about 90% of cell                                                                                                                                        volume
Centrioles It is present in all animal cells                                                    It is only present in lower plant forms.
Chloroplast Animal cells don't have chloroplasts and chlorophyll          Plant cells have chloroplasts and chlorophyll because they are                                                                                                                                     autotrophs which manufacture their own food
Cytoplasm        Present                                                                                    Present
Endoplasmic Reticulum (Smooth and Rough) Present                              Present
Ribosomes       Present                                                                                    Present
Mitochondria    Present                                                                                    Present
Plastids               Absent                                                                                    Present
Golgi Apparatus      Present                                                                              Present
Plasma Membrane   They have only cell membrane                                    They have a cell wall and a cell membrane
Microtubules/ Microfilaments   Present                                                          Present
Flagella    Flagella may be found in some animal cells                                 Flagella may also be found in some plant cells
Lysosomes    Lysosomes occur in cytoplasm.                                               Lysosomes usually not present.
Nucleus           Present                                                                                        Present
Cilia                PreseIt                                                                                           It is very rare.

A Summary Table OF Cell Organelles and their Functions

Part Function Found in
Cell membrane The cell membrane is selectively permeable. What this means is that it allows the passage of some substances through it while inhibiting the passage of others. Oxygen, food molecules, and waste products all ought to pass through the cell membrane. It controls what substances can move into and outside of the cell Plant and animal cells
Cytoplasm This is a jelly-like substance, upon which chemical reactions takes place in the cell. In plant cells the cytoplasm is a thin lining, while in animal cells the majority of the cell is cytoplasm. Plant and animal cells
Nucleus This takes charge and controls what takes place in the cell. It carries genetic information Plant and animal cells
Chloroplast The chloroplast is the place where photosynthesis occurs. It contains a green pigment known as chlorophyll. Plant cells only
Vacuole This is made up of a liquid known as cell sap, which keeps the cell rigid. Plant cells only
Cell wall The cell wall is made of a tough material known as cellulose, which supports the cell Plant cells only
Here, what we are looking at is the eukaryotic cells of plants and animals. Eukaryotic cells are differentiated from the more primitive prokaryotic cells by the presence of:

• Cytoplasmic membranous organelles

• A nuclear membrane or true nucleus

• Chromosomal proteins.

Our primary discussion here is on eukaryotic organelles, their functions inside the cell and the way they differ between plant and animal cells.

1. The Nucleus:
The nucleus is a home for the majority of genetic material of a cell. The nucleus is the "brain" of the cell and controls all activity that takes place inside the cell with the help of DNA as a outline to direct the production of proteins in the cell.

2. The Ribosomes:
The ribosomes function is to synthesize protein for the entire nucleus. They transport together all the raw ingredients like the RNA which are the replicas of the original DNA and amino acids to manufacture proteins. The proteins manufactured are very vital to cell and the optimum function of the organism.

Think of proteins as machinery for cell functions much like electricity and plumbing are essential in a real city. For example, enzymes are a type of protein without which life could not exist. The big and small subunits of ribosomal RNA translate an mRNA strand into a polypeptide chain.

3. The Endoplasmic Reticulum:
There are two types of endoplasmic reticulum (ER). The first on is the smooth endoplasmic reticulum and the second rough endoplasmic reticulum. This broad network of endoplasmic reticulum comprises about one half of all membranous tissue of the cell.

It is the site for membrane and protein synthesis. The Endoplasmic Reticulum system is very much like a road system that leads to an industry. Goods are produced in the factory and are transported to where it is needed through the same transport system

The Rough Endoplasmic Reticulum is thus named because of the presence of ribosomes along its membrane which is the source of proteins. Smooth Endoplasmic Reticulum does not have ribosomes and is in charge of lipid synthesis and processes a multiplicity of metabolic processes like the detoxification of drug.

4. Cell Membrane and Cell Wall
The cell membranes are present in animal cells while cell walls are present in plant cells. Cell walls and cell membranes have related functions. Just akin to a city outer limit, cell membranes enclose the cell and have the capability to control what enters in and out of the cell and by so doing, it regulates internal balance.

These membranes as well protect the inner cell from exterior forces. Cell walls, just like our city analogy, are much stronger than cell membranes and their function is to protect the cells from exploding in exceptionally hypotonic or diluted solutions.

5. Cytoskeleton:
The cytoskeleton is composed of an internal framework, which makes available to each one of the cell its distinctive shape and high level of organization that it contains. It is very significant for the movement of the and also for mitotic cell division or mitosis.

6. Cytoplasm:
Cytoplasm is a semi-fluid or gelatinous substance located inside the cell. The cytoplasm covers moderates and protects the inner organelles.

It is the cell background or surface area and is available anywhere in the cell where there are no organelles present. It is therefore very similar to the lawns and parks of our city which are normally cited where there are no residential or commercial houses.

7. Golgi Apparatus:
Golgi apparatus functions as a post office which is used for the transportation of the manufactured food by the endoplasmic reticulum and ribosomes to the rest of cell.

8. Chloroplasts:
Chloroplasts are organelles that are visible in the plant cells alone. They contain pigment known as chlorophyll which traps the energy of the sun to manufacture food for the plant during the process of photosynthesis.

Just similar to solar energy plant they make use of sunlight to manufacture energy for the plant. Chloroplasts are the place where photosynthesis- occurs in plants.

Photosynthesis is the process in which the plant makes use of carbon dioxide, water and sunlight to manufacture energy in the form of glucose for the plant cell as well as heterotrophs-animals that depends on plant for their food production.

9. Mitochondria:
Mitochondrion is present in both plant and animal cells and is the site where cellular respiration occurs. Through cellular respiration which would be covered in detail when explaining the process of photosynthesis and Respiration, a substance known as ATP is formed this is used for energy by the cell.

10. Lysosomes:
The lysosomes are digestive sacs that possess the tendency to be broken down into macromolecules in the cell through the process of hydrolysis. The digestion is carried out through the lysosomal enzymes located in the lysosome.

Lysosome is responsible with the disposal of excessive or bulky macromolecules in the same way the waste disposal in a city does. Lysosomes help to keep unnecessary or bulky macromolecules from mounting up in the cell.

11. The Cell Vacuoles and Vesicles:
These are similar in nature and function as membrane sacs that perform a lot of functions as control units for whatever thing that is in surplus in a city. They can contain a lot of substances starting from complex organic molecules to simple surplus water.

Plant cells possess a central vacuole that is very essential in keeping up and sustaining the turgidity of plants.

BIOLOGY: CELL AND IT'S ENVIRONMENT

from Femosky110 on 06/11/2020 11:36 AM

The Cell in Its Environment-Physical and Biophysical Processes
Substances can move into and out of a cell through its semi-permeable cell membrane. There are three different processes through which materials can move in and out of a cell. They are:

 

• Through the process of diffusion,

• Through the process of osmosis and

• Through the process of active transport.

Diffusion is the major process through which small molecules move in and out across the cell membrane region of higher concentration to a region of lower concentration.

The concentration of a substance is the amount of that particular substance in a given volume of liquid. Diffusion results as a result of movement and collision of molecules. The collisions of the molecules are what caused the molecules to thrust away from one another and spread out.

Molecules would normally diffuse through the cell membrane into a cell when the contents of the cell are of a lower concentration than the surrounding solution. The diffusion of water molecules through a semi permeable membrane is known as osmosis.

Due to the fact that cell function effectively without sufficient water, the majority of cellular processes depend on osmosis.

In osmosis, the molecules of water travel through the process of diffusion from a region of higher concentration to a region of lower concentration.

The movement of dissolved substances through a cell membrane without the use of cellular energy is referred to as passive transport. Diffusion and osmosis are two types of passive transport.

When there is a need for the cell to assimilate materials that are in higher concentration inside the cell than outside the cell, the movement of the materials requires energy.

On the contrary, active transport is the movement of materials through a cell membrane with the use of cellular energy. The major variation between passive transport and active transport is that active transport necessitates the use of cell's own energy while passive transport does not.

Cells have many ways of transporting materials through active transport. In one method, especially in the transportation of protein molecules, the cell membrane "lift up" molecules outside the cell and transport them inside the cell.

Another method of active transport is through engulfing. In this case, the cell membrane envelops or engulfs a particle and forms a vacuole inside the cell.

The majority of the cells are highly small. This is because the all particles have to move in and out of the cell through the cell membrane. On entering inside the cell, it is transported to its target through a stream of moving cytoplasm.

In an extremely large cell, streams of cytoplasm ought to travel farther to transport materials from the cell membrane to every part of the cell.

In a nutshell, Osmosis can be defined as:
• Diffusion of a solvent (frequently water molecules) through a semi permeable membrane from an area of low solute concentration to an area of high solute concentration.

• Net movement of water molecules through a semi-permeable membrane from an area of higher water concentration to an area of lower water concentration.

• The tendency of water to move from a hypotonic solution (lower concentration of dissolved substances) to hypertonic solution (higher concentration of dissolved substances) through a semi-permeable membrane

In biological processes, osmosis is very significant since a lot of biological membranes are semi permeable in nature, and it leads to diverse physiological effects.

For instance, when an animal cell is placed into a hypertonic surrounding- a surrounding with lower water concentration- the water will depart from the cell resulting to a shrinking of the cell.

When an animal cell is placed in a hypotonic environment, or an environment that is of higher water concentration, the water molecules will move into the cell causing the cell to swell. If osmosis continues and becomes extreme the cell will finally burst.

In a plant cell, extreme osmosis is barred as a result of the osmotic pressure exerted by the cell wall which stabilizes the cell. In fact, osmotic pressure is the major cause of support in plants.

On the other hand, if a plant cell is placed in a hypertonic surrounding, the cell wall cannot prevent the cell from losing water. This normally leads to a condition known as flaccidity or the shrinking of the cell.

Plasmolysis
This can be defined as the shrinking of protoplasm away from the cell wall of a plant or bacterium as a result of water loss from osmosis and in so doing leading to gaps between the cell wall and cell membrane.

When a plant cell is immersed into a highly concentrated solution, water diffuses out of the cell, and turgor pressure of the cell is lost. This makes the cell to become flaccid. Additional loss of water will lead to plasmolysis, and finally to cytorrhysis which means the total collapse of cell wall.

Plasmolysis only occurs in severe situations and seldom happens in nature. It is induced in the laboratory by immersing cells in strong saline or sugar solutions to give rise to exosmosis, frequently with the use of Elodea plants or onion epidermal cells.

Wilting and Plasmolysis
Plasmolysis is the separation of plant cell cytoplasm from the cell wall due to excessive loss of water. It is unlikely to happen naturally except in rigorous situations. Plasmolysis is induced in the laboratory by immersing a plant cell in a powerfully saline or sugary solution, so that the plant losses water through the process of osmosis.

Diffusion and Osmosis
Diffusion
Diffusion is the process by which molecules move from areas of high concentration, to areas of low concentration. When the molecules are even throughout a space - it is referred to as equilibrium state.

Concentration gradient: This is the difference between concentrations in a given environment.

Molecules will always travel down the concentration gradient, toward areas of smaller concentration. Example: food coloring that disperses out in a glass of water the dispersal of the fume from an air freshener sprayed in a room.

Semi Permeable membranes: These are membranes that allow the passage of some things while at the same time disallowing the passage of other things through it. Example of a semi-permeable membrane is the cell wall. It allows water and oxygen to pass freely through the cell's membrane, by diffusion

Osmosis means the diffusion of water across a membrane. Water will normally travel in the direction where there is a high concentration of solute. In other words where there is a lower concentration of water.

Salt is a solute and when it is concentrated inside or outside the cell, it will pull the water up to its direction. This is also the reason why we are thirsty after eating salty food.

Type of Solutions:
1. Isotonic Solutions: Iso means the same

When the concentration of solute (salt) is the same on both sides, the water will travel back and forth but it won't have any effect on the overall amount of water on the two sides.

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2. Hypotonic Solutions

"HYPO" means less. Therefore a hypotonic solution is a solution that contains less solute (salt) molecules outside the cell which leads to intake of water from the outside into the cell.

This leads to the cell gaining water and growing bigger. In plant cells, the central vacuoles will get filled up and the plant turns firmer and more rigid. Thus the plant's cell wall prevents the plant from bursting.

In animal cells however when this happens, the cell possibly will be in risk of bursting. Animal cell organelles known as the contractile vacuoles would normally pump water outside of the cell to avert this danger.

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3. Hypertonic Solution:

HYPER means more. Thus A hypertonic solution is a solution that contains more solute or salt molecules outside the cell than inside the cell. This would normally result to water being taking outside of the cell.

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In plant cells, the central vacuole loses water to the surrounding leading to the shrinkage of the cells and wilting of the plant.

In animal cells, this also results to the shrinkage of the cell. The situation could lead to death both in plant and animal cell.

This is why it is unsafe to drink sea water . Dehydration would normally be hastened up by intake of salty water. This is also why "salting farm lands is a common war practice with the aim of causing the death of crops in the farm to create famine.

Diffusion and Osmosis are both types of passive transport. What this means is that to transport materials in and out of the cell through either osmosis or diffusion, there is no energy requirement.

Occasionally, big molecules are unable to pass through the plasma membrane, and are assisted to pass across by carrier proteins. This process is referred to as a facilitated diffusion.

Diffusion is which is the net movement of a substance like an atom, ion or molecule from a region of high concentration to a region of low concentration can as well be defined as the movement of a substance down a concentration gradient.

A gradient is an alteration in the value of a quantity like concentration, pressure and temperature with the change in another variable like distance.

For instance, an alteration in a concentration across a distance is referred to as a concentration gradient. An alteration in the pressure across a distance is referred to as a pressure gradient while an alteration in temperature through a distance is referred to as a temperature gradient.

The word diffusion is obtained from the Latin word, "diffundere", which means "to disperse". If a substance is being dispersed, it is being transported from a region of high concentration to a region of low concentration.

A distinctive characteristic of diffusion is that it leads to mixing or mass transport, without needing bulk motion or bulk flow. Therefore, diffusion ought not to be mistaken for convection, or advections, which are other transport phenomena that make use of bulk flow to transport particles from one place to another.

Osmosis on the other hand is the spontaneous net movement of solvent molecules via partly permeable membrane into a region of higher solute concentration, in the direction that have the tendency of equalizing the solute concentrations on the either sides.

The osmotic pressure is used to explain the pressure needed to sustain equilibrium without any net movement of solvent. Osmotic pressure is a colligative property. This means that the osmotic pressure depends on the molar of the solute but not on its characteristics.

In biological systems generally, biological membranes are semipermeable and are not permeable to bigger and polar molecules, like ions, proteins, and polysaccharides. They are only permeable to non-polar and/or hydrophobic molecules such as lipids and small molecules such as oxygen, carbon dioxide, nitrogen, and nitric oxide.

Permeability of materials across the cell membrane depends on solubility, charge, or chemistry, in addition to the size of the solute. Water molecules pass through the plasma membrane, tonoplast membrane (vacuole) or protoplast by diffusing across the phospholipid bilayer throough aquaporins.

This means small trans-membrane proteins comparable to those in charge of facilitated diffusion and ion channels. Osmosis makes available the key way through which water is transported in and out of cells.

The turgor pressure of a cell is principally maintained by osmosis crosswise the cell membrane stuck between the cell center and its comparatively hypotonic environment.

BIOLOGY: ORGANISATION OF LIFE

from Femosky110 on 06/11/2020 11:33 AM

Organization of Life: Levels of Organization of Life:
1. Cell-Single celled organisms: In these organisms, a single cell usually carries out all the body processes. Examples of organisms that exist as single cell are Amoeba, Euglena and Paramecium.

 

2. Tissue: Some organisms exist as a tissue which performs all the life functions example is the Hydra. Details about hydra are explained further down in the tutorial.

3. Organ: Some organisms exist as an organ like the organ of storage in the onion bulb,. Another example of plant organ can be found in rhizome. Heart is an animal organ which is part of a system in the body of multicellular organisms.

4. System: Mammalian system and system in flowing plants, reproductive system, excretory system etc.

5. Complexity of organization in higher organisms, the advantages and disadvantages

In unicellular or single-celled organisms, the cell carries out the whole of the life functions on its own while in multicellular or many celled organisms, there are various levels of organization that exist among them.

Individual cell in addition to performing a particular function as well work jointly with other cells for the wellbeing of the entire organism. Thus there is division of labour among all the cells that the organism is composed of and each of the cells is dependent on the other to function effectively.

The five levels of organization in multicellular organisms are:
1. The Cells: The cell is the basic unit of life. It is the fundamental unit of structure and function of life. It may perform a specific function in the body of a living organism. Examples of cells are- blood cells, nerve cells, bone cells, etc.

Cells are made up of organelles which take care of everything starting from housing the cell's DNA, to the manufacture of energy. Processes that take place inside the body are carried out on a cellular level.

For instance during the movement of the leg, it is the function of the nerve cells to transmit this signal from your brain to the muscle cells in your leg.

2. Tissues: The tissue is composed of cells that have similar structure and function and which work together to carry out a particular function. Examples of tissues are blood, nervous, bone, etc.

Human beings have 4 fundamental tissues: connective tissue, epithelial tissue, muscle tissue, and nerve tissue. Animal tissue can be subdivided into 4: epithelial tissue, connective tissue, muscle tissue, and nervous tissue.

3. Organs: Organs are composed of tissues that work together to perform a specific function. Examples of organs are the heart, brain, skin and so on. For instance, the brain is made up of a lot of different types of tissues which include the nervous and connective tissues.

4. Systems: The system is a group of tissues to work together to achieve a particular function in an organism. Examples of systems are the circulatory system, nervous system, skeletal system, etc.

The Human body is made up of 11 systems which include- circulatory, digestive, endocrine, excretory or urinary, immune or lymphatic, integumentary, muscular, nervous, reproductive, respiratory, and skeletal system.

All these systems work together to keep the body functioning optimally. For example nutrients gotten through the digestive system are transported throughout the body by the circulatory system. In the same way, the circulatory system circulates the oxygen that is assimilated by the respiratory system.

5. Organisms: This is the entire living things that can perform all basic life processes. This means that such living thing can take in materials, discharge energy from food, free wastes, grow, respond to the stimuli in the surroundings, and reproduce.

The are normally made up of systems which combine together to form the organism but an organism can as well be composed of only a single cell like in the case of bacteria or protists such as bacteria, amoeba, mushroom, sunflower.

Living organisms are extremely ordered and possesses the ability to grow, develop, and reproduce. Multi-cellular organisms in addition to human beings depend on the collaboration between organs, tissues, cells, and system to exist.

The levels of organization of life in the right order is therefore

cells - tissues - organs - organ systems - organisms.

The pyramid of life is a hierarchical structure for the organization of life.

Examples of Plant and animal Cells
Cells are extremely small. They are the basic building blocks of every animal and plant. The pictures below show example of plant and animal cell as seen from a microscope.

Animal cell: The Cheek cells

These are cheek cells, seen through a microscope:

Plant cells: Onion cells

Onion cells as seen through a microscope:

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The Kingdom Protista are made up of single-celled organisms that posses a true nucleus. This means that they are eukaryotic. Protista may be either autotrophic or heterotrophic.

This means that some of them manufacture their own food while the rest depend on already manufactured food. The mode of movement by protists is depends on their physical features

A few protozoa have pseudopodia which has the ability to extend the cell membrane and thrust forward to surround a particle of food like you would obtain in amoeba. A protist that has one tail-like structure is refered to as a flagellate.

Such an organism would use its flagellum to beat back and forth and push itself through the water like you would obtain in trypanosome and trichosomes. Some Protozoa are enclosed with minute hair-like structures known as cilia which move back and forth swiftly pushing the organisms through the water.

A paramecium is an example of a ciliated organism. Some Protozoa have axopodia, or pencil-like structures, that assist them to be planktonic or floaters in the water. Radiolaria are marine examples of protozoa bearing this structure

There are a lot of debates regarding if protozoa are all one-celled organisms or if they are all one-celled organisms that are heterotrophs. Scientists, who researched on these groups, argue on how to classify a few of these like euglena and dinoflagellate.

The majority of protozoa are useful in that they are significant in lower levels of the food chain. They make available food for living things like snails, clams, and sponges. A few protozoa have the ability of causing diseases in humans and other animals.

Some diseases caused by protozoa in human beings are malaria, black fever, sleeping sickness, and a number of forms of diarrhea.

Hydra is a genus of small, plain, fresh-water animals that is radial symmetrical. They are predators and belong to the phylum Cnidaria and the class Hydrozoa.

They are mostly found in the majority of unpolluted fresh-water ponds, lakes, and streams in the temperate and tropical climates and can be seen by softly sweeping an assembling net through weedy areas.

They are multicellular organisms which are frequently a few millimetres long and can be studied effectively through the help of a microscope. Biologists are particularly interested in Hydra as a result of their ability to regenerate. They also seem not to be old or die out of age.

Hydra
Scientific classification
Kingdom - Animalia

Subkingdom - Eumetazoa

Phylum - Cnidaria

Subphylum - Medusozoa

Class - Hydrozoa

Subclass - Leptolinae

Order - Anthomedusae

Suborder - Capitata

Family - Hydridae

Genus - Hydra Linnaeus

Motion and locomotion of Hydra
Whenever Hydra are startled or attacked, they retract their tentacles to form small buds. They can as well retract their entire body column into a small gelatinous sphere. Hydra usually reacts in the same manner irrespective of the direction of the stimulus, and this might be as a result of the simplicity of the nerve net.

The sessile or sedentary behavior of Hydra
Hydra is usually sedentary or sessile but can on occasional basis transport itself swiftly particularly when hunting for food. They normally do this by bending over and fastening themselves to the substrate with the mouth and tentacles and after that let go of their feet, which makes available the typical attachment.

This process in hydra is referred to as looping. The body subsequently bends over and makes a fresh position of attachment with the foot.

Through this process of "looping" or "somersaulting", a Hydra can be in motion quite a lot of inches (c. 100 mm) on a daily basis. Hydra may also move about through amoeboid movement of their bases or by merely coming off the substrate and hovering away through the water current.

Reproduction and life cycle of Hydra
When there is a lot of food, are plentiful, loads of Hydra reproduce asexually by generating buds in the body wall. These buds grow to be small adults and merely breaking away when they are full-grown.

When conditions are unsympathetic, habitually before winter or in poor feeding and nutritional situations, some Hydra undergo sexual reproduction. Inflammations in the body wall expand into either a straightforward ovary testes.

The testes discharge free-swimming gametes into the water, and these possibly may fertilize the egg in the ovary of another individual hydra.

The fertilized eggs ooze a hard outer coating, and, as the fully developed hydra dies, these dormant eggs get discharged to the bottom of the lake or pond to wait for favorable conditions, at which point they hatch into nymph Hydra. Some type of Hydra like Hydra circumcincta and Hydra viridissima, are hermaphrodites and may at the same time bring into being both testes and an ovary.

Various members of the Hydrozoa pass through a body alteration from a polyp to an adult form known as a medusa. Nevertheless, all Hydra, regardless of being hydrozoans, hang about as polyps all the way through their lives.

Feeding of Hydra
The feeding in Hydra is majorly on minute aquatic invertebrates like as Daphnia and Cyclops.

When feeding, Hydra extends their body to their highest length and after that little by little extends their tentacles. In spite of their plain construction, the tentacles of Hydra are amazingly extensible and can be extended up to four to five times the length of the entire body.

Just immediately they are completely extended, the tentacles are bit by bit maneuvered more or less waiting to make contact with an appropriate prey animal. Once they come in contact, nematocysts on the tentacle shoot into the prey, and the tentacle then coils over the prey.

Just within a space of 30 seconds, the majority of the rest tentacles would have already united in the attack to suppress and hold back the besieged prey. Just about two minutes, the tentacles will have bordered the prey and stirred it into the opened mouth opening.

In a space of about ten minutes, the prey will have been completely engulfed into the body cavity, and digestion will have been on track. Hydra is able to elongate its body wall by a long way in order to digest prey that is two times its size.

After two or three days, the hard to digest parts of the prey will be released through the contractions of the aperture in the mouth.

The feeding attitude of Hydra illustrates the cleverness of what seem to be just a mere nervous system.

A few species of Hydra occur in a joint relationship with a combination of types of unicellular algae. The algae are sheltered from predators by Hydra and, in return, photosynthetic products from the algae are valuable as a source of food to Hydra.

BIOLOGY: CONCEPT OF LIVING THINGS

from Femosky110 on 06/11/2020 11:29 AM

Concept of Living things
Living things are vibrant as their inner chemistries make use of resources, transfer energies, and manufacture wastes. These alterations cannot be persistent in a protected chamber with no relationship to the world around them.

 

Organisms ought to absorb materials, discharge materials, and make efforts to keep away from things that would take their life away, either from instant threats things wanting eat them up, or a toxin, or potentially destructive germs or long-term needs like discovering required resources, or ensuring that it doesn't get harmed by its own waste.

This necessitates the capability of picking up signals from the surroundings and acting in response to them. This can be easily achieved as a few molecule-based "switches" are, or as intricate as the information to take in and process and enable you to elicit responses every.

The degree of communication depends upon the "size" of the environment being considered. Every one of the cell exists in a direct environment of atoms and molecules, typically in a water-based broth.

Individuals live in minute environments that are merely their direct surroundings and fit into ecosystems that comprise, in assumption at the very least, all the global factors that influence them and which they in turn influence.

Not surprisingly, this is why any practical discussion requires limits to be enforced when during the study of every particular ecosystem.

Ecosystems have niches. Niches are sort of functional "slots" into which different types of organisms fit. Take for instance the majority of possible ecosystems possesses a niche or niches for top Predator(s), distinct by factors like the availability of prey but also land and water availability.

This is one more locale where biology is reductionist, making assumptions that that the functions of any ecosystem can be tacit and foreseen by awareness of all the "relevant" niches; this is as well one more area where embryonic properties can be exceptionally in convenient.

Classification of Living Things
Classification of living things is called "Taxonomy." This is when scientists put organisms into groups when they have things in common. The first groups they use are the Kingdoms. There are five kingdoms:

• Animal Kingdom

• Plant Kingdom

• Fungi Kingdom

• Protist Kingdom

• Moneran Kingdom

Every Kingdom is further sub-divided into minor groups, known as Phyla. Every Phylum is divided into slighter groups known as Classes, every Class is subdivided into Orders, every Order is divided into Families, every Family is further divided into Genera, and every Genus divided into Species.

A Species is a particular organism, not a group. A few examples of species are Southern Leopard Frog, Honey Mushroom, or White Oak. Every one of the seven types of groups exit in order from biggest to least, in this manner:

• Kingdom

• Phylum

• Class

• Order

• Family

• Genus

• Species

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As every group got divided into minor groups, the organisms look more and more identical. For example, a White-tailed Deer, an Eastern Gray Squirrel, and an Eastern Chipmunk are examples of Mammal n the same Class.

This is due to the fact of the things they have in common with each other more than with other animals, like the turtles, birds, or insects. Nevertheless, it is simple to observe that there are several huge differences between a deer, squirrels and chipmunks.

The White-tailed Deer is in the Aritiodactyla Order together with toed Hoofed Mammals, while squirrels and chipmunks are together in the Rodentia Order (Rodents).

In reality, squirrels and chipmunks have a lot in common. They are also in the same Family, the Sciuridae Family. Nevertheless, despite the fact that squirrels and chipmunks look alike, they still possess some differences.

The Eastern Gray Squirrel is classified among the Sciurus Genus, while the Eastern Chipmunk is classified among the Tamias Genus.

You would observe that each one of these groups have names which are funny. This is so because Scientists globally consented to making use of the ancient language of Latin to name organisms, and their groups.

Occasionally a group will possess a "Common Name" and a scientific Latin name. For instance a Family of frogs that are given Scientific Latin name "Ranidae" is commonly known as "True Frogs in English.

Also, the entire organism's Species have scientific Latin name. A Bullfrog for example is as well referred to as "Rana catesbeiana." A White-tailed Deer is referred to as "Odocoileus virginianus." A Monarch butterfly is referred to as "Danaus plexipus."

What makes it simpler to know all the names is the knowledge that a Species always bear a first and a last name; and that the first name is as well the name of the Genus group that Species belongs to.

So the Monarch butterfly is referred to as Danaus plexipus and it is in the Danaus genus. Take note that the first name of a Species is constantly written in cap lock whereas the second name is written in lower case.

The classification of a Bullfrog enable you know the groups it belongs to:
• Bullfrog (Rana catesbeiana)

• Kingdom: Animal

• Phylum: Chordate

• Class: Amphibians

• Order: Salientia

• Family: Ranidae

• Genus: Rana

• Species: Rana catesbeiana (Bullfrog)

See below two examples of classifications. Take note that in plants, Phyla are known as "Divisions."

Animal-Eastern Gray Squirrel:

Scientific Classification
KINGDOM - Animal

PHYLUM - Chordate

CLASS - Mammal

ORDER - Rodentia

FAMILY - Sciuridae

GENUS - Sciurus

SPECIES - Sciurus, carolinensis

Plant-White Oak:
Scientific Classification
KINGDOM - Plant

DIVISION - Magnoliophyta

CLASS - Magnoliopsida

ORDER - Fagales

FAMILY - Fagaceae

GENUS - Quercus

SPECIES - Quercus alba

Immediately you have mastered the way classification works, you would found it simple to learn and compare a group of organisms.

Explanations of Classification Group
Every organism is divided into five Kingdoms:

• Animal Kingdom: These are organisms that typically move around and get their own food.

• Plant Kingdom: These are organisms that produce their own food and do not vigorously move about.

• Fungi Kingdom: These are organisms that suck up food from living and non-living things.

• Protist Kingdom: These are organisms that possess single but composite cells.

• Moneran Kingdom: These are organisms that contain single, uncomplicated cells.

Animal Kingdom
The Animal Kingdom is divided into many Phyla. Every one of the Phylum group have organisms that have similar features or characteristics. See below examples of Phyla:

1. Chordate Phylum:
This phylum comprises all the animals which posses a backbone. Examples are: Fish, Reptiles, Birds, Amphibians, and Mammals.

2. Arthropod Phylum:
This phylum is composed of animals with "jointed appendages. All animals that belong to this phylum possess an exoskeleton which means a skeleton that it on the exterior part of the body. Examples are: Insects, Arachnids, and Crustaceans.

3. Mollusk Phylum:
This phylum is soft-bodied animals that occasionally have a tough shell. Examples are Snails, Slugs, Octopus, Squid, Clams, Oysters, and Mussels.

Annelid Phylum: These organisms are segmented worms. They are: Earthworms and Leeches.

Rotifer Phylum: This is minute, microscopic animals that have wheel-shaped mouth and miniature hairs.

Nematode Phylum: These are extremely minute worms that have no segments in their bodies. They are also known as Roundworms.

Tardigrade Phylum: This phylum is sluggish-moving animals with four body segments and eight legs. Example is the Water Bears.

Cnidarian Phylum: This is tender- bodied, wobbly animals with tentacles and venom glands. Examples are: Hydra, Jellyfish, Sea Anemones, and Coral.

Echinoderm Phylum: These are regularly spiky animals, with quite a few "arms" shooting out from the middle of its body. Examples are: Starfish and Sea Urchins.

Platyhelminthes Phylum: These are tender and flat-bodied worms. They are Planarians and Tapeworms for instance.

Chordate Phylum Arthropod Phylum Mollusk Phylum
Annelid Phylum Rotifer Phylum Nematode Phylum
Cnidarian Phylum Tardigrade Phylum Platyhelminthes Phylum
Plant Kingdom
In place of Phyla, the Plant Kingdom is divided into Divisions. Every Division group embraces organisms that possess things in common. See below a list of few plant Divisions:

1. Magnoliophyta Division:
This comprises every flowering plant. These plants possess leaves, stems, and roots. After blossoming, they develop fruits with seeds. Examples are the majority of crops, trees, shrubs, grasses, garden plants, and weeds.

2. Coniferophyta Divsion:
These are plants that bear cones. Examples are Pine Trees and Cedars.

3. Pteridophyta Division:
These are plants that possess roots and stems, but which are lacking flowers or seeds. In its place, they multiply through the process of spore formation. Examples are Ferns.

4. Bryophyta Division:
These are plants that have very minute sized leaves and stems. They also do not have roots and flowers. They normally grow extremely near to the ground Example is Mosses.

5. Lycopodiophyta Division:
biology
These comprise small plants that have green, branched stems, scale-like leaves but no flowers. They as well normally grow significantly stumpy to the ground. They include such plants like Club Mosses, Quillworts, and Spike mosses.

Magnoliophyta Division Coniferophyta Division
Pteridophyta Division Bryophyta Division
Lycopodiophyta Division
biology
Fungi Kingdom
Similar to the plant kingdom, the Fungi Kingdom is divided into Divisions as an alternative to Phyla. The entire Division group has organisms that have similar characteristics See a list of a few fungi Divisions below:

Basidiomycota Division:
These consist of a lot of dissimilar forms, the majority of which assist putrefy and break down wood, waste, and animal dung.

Protist Kingdom
The Protist Kingdom is divided into a number of Phyla. Every Phylum group consists of organisms with similar characteristics. Some examples of a list of protist Phyla are shown below:

Protozoa Phylum:
These are very small, minute organisms which replicate by dividing into half to turn into two new organisms. Examples are Amoeba, Paramecium, and Sporozoa.

Euglenophyta Phylum:
These are minute, infinitesimal organisms which possesses flagella. Flagella are small hair-like features that assist them to move about water. A number of them feed on algae and carry them inside their bodies, as their food. Example is the Euglena.

Moneran Kingdom
The kingdom Monera is divided into a lot of Phyla. Every one of the Phylum group have organisms with similar characteristics. See below a few moneran Phyla:

Bacteria Phylum: These organisms are exceptionally significant and can as well be awfully hazardous. They live everywhere there is humidity, together with inside animal's bodies. A number of them are diseases carriers.

Cyanobacteria Phylum: These organisms are as well referred to as Blue-green Algae. These algae vary from the Green Algae originated in the Plant Kingdom.

Viruses
Scientists have not been able to come into conclusion of where to place viruses. Presently they are not classified into any of the five Kingdoms.

Differences between Plants and Animals
1. Plants belong to the kingdom plantae while animals belong to the kingdom animalia.

2. Plants do not move from one place to the next while animals move from one place to the other.

3. Plant cells have cell walls while animal cells don't have a cell wall.

4. Animals have more developed sensory and nervous system. Animals have intelligence to evaluate situations and make decisions while plants don't.

5. On basis of cell structure, plant cell has a cell wall and a coloring pigment referred to as chlorophyll but this is lacking in animal cell.

6. Plants manufacture their own food through the process of photosynthesis while animals cannot manufacture their own food but only depend on plants for their feeding.