25.11.2019  Author: admin   Simple Wood Craft Ideas
Heterotrophism This is a mode of nutrition in which organisms take in already manufactured complex benhc substances such as carbohydrates, proteins and lipids. The plants were also classified as herbs, woodwork bench and vice pdf, shrubs. Quote Request. This is because enzymes get denatured and their active sites get destroyed. This makes sharing scientific knowledge on organisms very difficult. There are many small pores on the epidennis known as stomata singular-stoma through which exchange of materials occur. The movement of the water molecules continues until the separate benc have the same concentrations.

Nutrition Plants And Animals Introduction Nutrition refers to the process by which living organisms obtain and assimilate utilize nutrients. It is one of the fundamental characteristics of living things. The nutrients obtained Best Height For Woodworking Bench Nz are useful to the living organisms in many ways: a The nutrients are required for growth and development of the living organisms. Modes of nutrition There are two main nutrition modes: a Autotrophism mode of nutrition through which living organisms manufacture their own food from simple inorganic substances in the environment such as carbon IV oxide, water and mineral ions.

Organisms that make their own food through this mode are autotrophs. Heterotrophs are the organisms that feed on already manufactured food materials. Autotrophism In this mode of nutrition, organisms manufacture their own food from readily available materials in the environment. These organisms use energy to combine carbon IV oxide, water and mineral salts in complex reactions to manufacture food substances.

Depending on the source of energy used to manufacture the food, there are two types of autotrophism: a Chemosynthesis This is the process whereby some organisms utilize energy derived from chemical reactions in their bodies to manufacture food from simple substances in the environment.

This nutrition mode is common in non green plants and some bacteria which lack the sun trapping chlorophyll molecule. Such organisms often have chlorophyll which traps the required sunlight energy.

This mode of nutrition is common in members of the kingdom Plantae. Some protoctists and bacteria are also photosynthetic. Importance of Photosynthesis 1. Photosynthesis helps in regulation of carbon IV oxide and oxygen gases in the environment. Photosynthesis enables autotrophs make their own food, thus, meet their nutritional requirements. Photosynthesis converts sunlight energy into a form chemical energy that can be utilized by other organisms that are unable to manufacture their own food.

Photosynthesis largely occurs in the leaf. To understand the process of photosynthesis, it is important to understand the leaf structure. The leaf margin can be smooth, dentate, serrated or entire. The size of a leaf depends on its environment. Plants in arid areas have small sized leaves with some leaves reduced to needle like shape. This helps reduce the rate of water loss in such plants.

However, the plants in areas of water abundance have broad leaves to enable them lose the excess Water. It is a thin non-cellular, Waxy, transparent and waterproof layers that coats the upper and lower leaf surfaces. Functions of the cuticle a Being waterproof, it minimizes water loss from the leaf cells to the environment through transpiration and evaporation.

Functions of the epidermis: a It protects the leaf from mechanical damage. There are many small pores on the epidennis known as stomata singular-stoma through which exchange of materials occur. The opening and closing of the stomata is controlled by the guard cells.

Each stoma is controlled by two guard cells. The guard cells have chloroplasts and are bean shaped. They have thicker inner cell wall and thinner outer cell wall. Adaptations of the guard cells They have deferentially thicker walls to enable them bulge as they draw water through osmosis from the neighboring cells making them to open the stomata. They contain chloroplasts that manufacture sugars which increase osmotic pressure of the guard cells.

As they draw water through osmosis, they bulge making the stomata to open. Its cells are regular in shape. Its cells contain numerous chloroplasts for photosynthesis. Their close packing and location just below the epidermis enables them to trap maximum sunlight for photosynthesis. Location of palisade layer on the upper surface explains why upper leaf surfaces are greener than the lower surfaces. This leaves large airspaces between the cells which permits free circulation of gases carbon IV oxide and oxygen into the photosynthetic cells.

Spongy mesophyll cells contain fewer chloroplasts compared to palisade cells. Vascular bundle is made of phloem and xylem tissues. Xylem tissues conduct Water and some dissolved mineral salts from the roots to other plant parts while phloem translocates manufactured food materials from photosynthetic areas to other plant parts. Chloroplast This is the organelle in which photosynthesis takes place. It is an oval shaped double membrane bound organelle. Lamellae forms stacks at intervals called grana singular-granum.

Chlorophyll molecules are contained in the grana. Within the stroma. The strona contains enzymes and forms the site Where light independent reactions take place.

The leaf has numerous stomata through which photosynthetic gases diffuse. The leaf is thin to reduce the distance through which carbon IV oxide has to diffuse to the photosynthetic cells.

The palisade mesophyll cells contain numerous chloroplasts which contain chlorophyll molecules which trap sunlight energy for photosynthesis. The photosynthetic mesophyll is located towards the upper surface for maximum absorption of sunlight energy.

The leaf has an extensive network of veins composed of xylem which conducts water to the photosynthetic cells and phloem to translocate manufactured food materials to other plant parts.

The epidermis and cuticle are transparent to allow light to penetrate to the photosynthetc cells. Raw materials for photosynthesis Water Carbon IV oxide Conditions for photosynthesis Light energy Chlorophyll Photosynthesis Process Photosynthesis is a complex process that involves a series of reactions. It can be summarized into two main reactions. It occurs in the presence of light.

Without light it cannot take place. Light stage occurs in the grana of the chloroplasts. During light stage, two fundamental processes occur: i Photolysis of water This refers to the splitting of water molecules using sunlight energy to give hydrogen ions and oxygen gas. This is aided by the fact that the grana contain chlorophyll molecules that trap sunlight energy for photolysis.

The oxygen gas produced can either be released into the atmosphere or be utilized by the plant for respiration. ATP is an energy rich molecule that stores energy for use in the dark stage when sunlight energy could be unavailable. The energy that propels these reactions are derived from the ATP formed during light stage. Dark reactions take place in the stroma. Other food materials are then synthesized from the simple sugars through complex synthesis reactions.

The simple sugar formed in dark stage is quickly converted to starch which is osmotically inactive. When a lot of simple sugars accumulate in the chloroplasts, osmotic pressure of the guard cells would increase causing the guard cells to draw a lot of water through osmosis. This makes the guard cells to bulge and open the stomata. This can result into excessive water loss. To prevent, this, the simple sugars are quickly converted to starch. To test whether photosynthesis has taken place in a leaf, therefore, a test for presence of starch and not simple sugars is carried out.

This duration ensures that the leaf has photosynthesized. Put the leaf in boiling water for 10 minutes. This kills the protoplasm, denatures the enzymes and stops any chemical reactions in the leaf. Remove the leaf and put it in a boiling tube containing methylated spirit or alcohol and boil in a water bath. Boiling with methylated spirit or alcohol decolourises the leaf removes the chlorophyll.

This ensures that the leaf becomes white so that colour changes can be observed easily when iodine is added. Remove the leaf and wash off in hot water to remove methylated spirit and to soften the leaf. Spread the leaf on a white tile and add drops of iodine solution onto the leaf and observe.

Factors affecting the rate of photosynthesis a Carbon IV oxide concentration While the concentration of carbon IV oxide in the atmosphere is fairly constant at 0. At this point, other factors such as light intensity, water and temperature become limiting factors.

Beyond the optimum light intensity the rate of photosynthesis becomes constant. To this effect, plants photosynthesize faster on bright and sunny days than on dull cloudy days. Most plants require red and blue wavelengths of light for photosynthesis.

Light duration also affects photosynthesis rate. At very low temperatures the rate of photosynthesis is slow because the enzymes are inactive. As temperature increases, the rate of photosynthesis increases because the enzymes become more active. At extreme level of water shortage, rate of photosynthesis will be severely affected.

Experiment to investigate the gas produced during photosynthesis Requirements Water plant e. Procedure a Set up the apparatus as shown in the figure below b Place the set up in the sunlight to allow photosynthesis to take place. Note: In this experiment, sodium hydrogen carbonate is added to the water to boost the amount of carbon IV oxide in the water since water has a low concentration of carbon IV oxide.

A water plant is also selected because Water plants are adapted to photosynthesis under the low light intensity in water where terrestrial plants cannot easily photosynthesize. This experiment can also be used to investigate the factors affecting the rate of photosynthesis: 1 Carbon IV oxide concentration : Carry out the experiment using different amounts of dissolved sodium hydrogen carbonate e.

Illuminate the plant and vary the distance between the set up and the light source While recording the time it takes for the gas jar to fill or counting the number of bubbles peer unit time. Experiments on factors necessary for photosynthesis Light Requirements Methylated spirit, iodine solution, water, white tile, droppers, beaker, source of heat, boiling tube, light proof material e.

Procedure Cover two or more leaves of a potted plant with a light proof material. Place the plant in a dark place for 48 hours keeping the plant in the dark for 48 hours is to ensure that all the starch in it is used up.

This makes the leaves ideal for investigating whether starch would form in the experimental period. This is called destarching. Transfer the potted plant to light for 5 hours. Detach and uncover the leaves and immediately test for starch in one of the covered leaves and one that was not covered. Chlorophyll For this experiment, a variegated leaf is required. This is a leaf in which some patches lack chlorophyll.

These patches could be yellow. They lack chlorophyll hence photosynthesis does not take place in them. Procedure Detarch or remove variegated leaf that has been exposed to light for at least three hours. Draw a large diagram of the leaf to show the distribution of the chlorophyll Test the leaf for starch and record observations.

Chemicals Of Life These are chemical compounds that constitute the living organisms. Biochemistry is the branch of biology that deals with the study of the chemicals of life and their reactions. Chemicals of life include carbohydrates, proteins and lipids. Carbohydrates Are compounds of carbon, hydrogen and oxygen in the ratio of l. They have a general formula CH2O n where n represents the number of carbon atoms.

Carbohydrates are grouped into three categories: Monosaccharides These are the simplest carbohydrates. They include glucose, fructose, galactose. Their general formula is C6H12O6. Note: Most fruits are sweet tasting because they contain a lot of monosaccharides. Monosaccharide units can be combined to form complex carbohydrate molecules through a process known as condensation.

Water molecules are produced in the process. Functions They are the chief respiratory substrate. They are broken down to release energy in the body.

They are condensed to form complex important carbohydrates. Disaccharides These are complex sugars formeed by linking two monosaccharide units through condensation.

The bond that holds two monosaccharide units is called glycosidic bond. Examples of disaccharides include: Maltose-common in germinating seeds Sucrose-fruits and sugar cane. Sucrose is the form in which carbohydrates are transported in plants Lactose- found in milk Properties of Disaccharides They are sweet tasting They are crystallizable They are water soluble While they are non reducing sugars, some such as maltose is sugar reducing and is known as a complex reducing sugar.

They can be broken down into their constituent monosaccharide units through hydrolysis. Hydrolysis is the process through which complex molecules are broken down in the presence of water molecules. In living systems, hydrolysis is carried out by enzymes. However, in the laboratory, hydrolysis can be carried out by boiling the disaccharide in dilute aid such as hydrochloric acid.

Functions They are hydrolyzed into monosaccharides and respired on to yield energy They are the form in which carbohydrates are transported in plants due to their soluble and inert nature. Polysaccharides These are formed through linking of numerous monosacchride units through condensation. Their general formula is C6H10O5 ,, where n is a very large number. Properties of polysaccharides They are non sweet They do not dissolve in water They are non crystalline They are non-reducing sugars Examples of polysaccharides a Starch - Made by linking numerous glucose molecules.

It is a form in which carbohydrates are stored in plants. It is broken down to glucose in animals when blood glucose falls. It is a component of the cell wall d Chitin - A structural carbohydrate found in cell wall of fungi and arthropod exoskeletons Functions of polysaccharides They are storage carbohydrates; their insolubility and inertness makes them ideal for storing carbohydrates.

They are structural carbohydrates e. However, they contain lesser oxygen but higher hydrogen compared to carbohydrates. Building units for lipids are fatty acids and glycerol. To synthesize a molecule of lipid, three fatty acids and a glycerol molecule are linked through a condensation reaction.

There is one type of glycerol but numerous fatty acids There are different types of fatty acids. The property of a lipid therefore depends on the type of fatty acids that link up with the glycerol.

There are complex lipids such as phospholipids, steroids, waxes and cholesterol. These also form through condensation. Properties of lipids Fats easily change to oil when heated while oils easily solidify when cooled. They are insoluble in water but readily dissolve in organic solvents such as chloroform to form emulsions They are inert hence can be stored in tissues of organisms.

Functions They are a source of energy when oxidized. They yield more energy compared to carbohydrates when oxidized per unit weight.

However, they are less preferred as source of energy because they require a lot of oxygen to oxidize. In addition, they are insoluble hence not easy to transport to respiratory sites. They are a source of metabolic water. When oxidized, they yield a lot of metabolic water.

This explains why some desert animals such as camels store large quantities of fat in their bodies. Lipids offer protection to internal organs as they are deposited around them to act as shock absorbers. Lipids provide heat insulation when stored underneath the skin as they are poor conductors of heat hence do not conduct heat away from the body. Organisms in cold areas tend to be short and plump as they have fatter fat adipose. Lipids form structural compounds for instance phospholipids in cell membrane.

Complex lipids such as waxes in leaves help minimize water loss through transpiration. Some lipids mediate communication between cells Proteins These are compounds of carbon, hydrogen and oxygen. In addition, they also contain nitrogen and sometimes phosphorous or sulphur or both. Some proteins molecules contain other elements. In particular, haemoglobin contains iron.

Proteins are made up of amino acids. There are about twenty known amino acids. Amino acids are of two kinds: a Essential - These are those amino acids that cannot be synthesized by the body systems hence have to be supplied in the diet. An amino acid has an amino group, carboxyl group, hydrogen atom and an alkyl, R group. Amino acids differ from each other by the alkyl group. Proteins are of two kinds: a First class proteins - Contain all essential amino acids b Second class proteins - Proteins lack one or more essential amino acids Protein synthesis Two amino acids combine through a condensation process to form a dipeptide molecule Several amino acids link up to form a polypeptide chain.

Proteins are made up of long chain polypeptides. Properties of a protein depend on the type of amino acids present in its chain and the sequence in which the amino acids link up in the polypeptide chain.

Properties of Proteins They dissolve in Water to form colloidal suspensions in which the particles remain suspended in water. Strong acids, bases, detergents and organic solvents also denature proteins.

They are amphoten'c- possess both basic and basic properties. This property enables them to combine with other non protein substances to form conjugated proteins such as: Mucus- Protein plus carbohydrate Haemoglobin- Protein plus iron Functions of proteins a They are structural compounds of the body.

Cell membrane is protein in nature. Hair, nails and hooves are made up of protein keratin. Hormones are chemical messengers while enzymes regulate the speed of metabolic reactions. Haemoglobin molecule plays a crucial role in transportation of respiratory gases. Enzymes What are enzymes? Are organic catalysts that are protein in nature and regulate the rate of metabolic reactions.

They speed up or slow down the rate of metabolic reactions but to not get used up in the process. Types of enzymes a Extracellular : Are produced within the cells but used outside the cells e.

Importance of Enzymes They speed up the rate of chemical reactions that would otherwise be too slow to support life. Digestive enzymes breakdown complex food substances into simple foods that can be utilized by the cells. Some metabolic enzymes such as catalase play a vital role in detoxification making poisonous substances less harmful.

Enzyme nomenclature Two systems of naming enzymes have been adopted. Trivial naming This is where an enzyme is named by the scientist who discovered it. In trivial naming all enzyme names end in prefix —in. Examples Pepsin Theodor Schwann, German physiologist Ptyalin Anselme Payen, a French chemist- Substrates Amylose starch The reaction is then catalyzed and the end products released.

The enzyme is free to bind with another substrate molecule. The enzymes can be used again and again. Properties of Enzymes They are protein in nature; hence affected by temperature and pH. They are substrate specific e. They mostly take part in reversible reactions.

They regulate the rate of metabolic activities but are not used up. Factors affecting enzyme activity Temperature. Substrate Concentration. Enzyme Concentration. Enzyme co-factors and co-enzymes; Fe, Mg, Zn, Cu ions. Enzyme inhibitors. There are few collisions leading to low enzyme activity. As temperature increases, the kinetic energy of the enzyme and substrate molecules increases leading to increased collisions hence increase in enzyme activity.

This is because enzymes get denatured and their active sites get destroyed. Some enzymes work best under alkaline conditions e. Some also work better under acidic conditions e. However, most intracellular enzymes work better under neutral conditions. Altering the pH conditions would affect enzyme activity. For instance, sucrase enzymes can only breakdown sucrose.

Increase in substrate concentration increases the rate of enzyme activity since more active sites of the enzymes will be occupied and there will also be an increase in enzyme- substrate collisions leading to increased reaction. The reaction increases up to a point at which it becomes constant.

At this point, all active sites are utilized. The enzymes become the limiting factor of reaction. Increasing enzyme concentration would increase the rate of enzyme activity. At low enzyme concentration, rate of enzyme activity is low because there are fewer sites and also fewer enzyme-substrate collisions that would lead to reactions. Increasing enzyme concentration increases rate of enzyme activity since there will be an increase in number of active sites and enzyme-substrate collisions.

At optimum enzyme concentration, substrate concentration is the limiting factor. Increasing substrate concentration increases the rate of reaction. Without them, most enzymes would not function properly. Co- factors include mineral ions like iron, magnesium, copper, manganese, zinc as well as vitamins. They are used again and again since like enzymes, they do not get used up during the reactions.

Some enzymes will not function without them. Most co-enzymes are derivatives of vitamins. They are of two types: 1. Competitive 2. Non- competitive Competitive inhibitors These are chemical substances which are structural analogs of the substrates i.

They bind with the enzymes and do not disentangle easily they stay in the enzyme active site for a long time thereby slowing down the rate of enzyme activity.

The reaction can be increased by increasing the substrate concentration. Non competitive inhibitors These are inhibitors that do not resemble the substrate molecules but they combine with the enzyme at any site other the active site and alter the structure of the active site of the enzyme.

The normal substrate, therefore, fails to bind to the active site leading to decreased rate of reaction. Note that these substances do not compete for the active sites of the enzymes. The enzymes are destroyed permanently hence the effect cannot be reversed. Examples of non competitive inhibitors Heavy metals such as lead, mercury, silver , Cyanide, organophosphates such as malathion.

Heterotrophism This is a mode of nutrition in which organisms take in already manufactured complex food substances such as carbohydrates, proteins and lipids. Heterotrophs are organisms that feed on already manufactured food substances.

These substances are broken down in the bodies of the Heterotrophs into simple soluble food substances that can be absorbed and be utilized by the cells. Modes of Heterotrophism There are four main heterotrophic modes on nutrition: Holozoic- Where organisms ingest, digest and assimilate solid complex food substances.

Saprophytism — Where organisms feed on dead decaying matter causing decomposition. Parasitism- a feeding association in which one organism parasite feeds on or obtain nutrients on another organism, the host.

The parasite benefits but the host does not. Some of the parasites cause diseases to the hosts and damage their tissues thereby weakening them. Dentition Large animals depend on complex manufactured food substances. These food substances once ingested must be broken down to simpler forms that can be utilized by the cells. The breakdown is both physical and chemical. Most of the large animals have teeth to enhance physical breakdown of the complex food substances. Dentition refers to the description of types of teeth, their arrangement and specialization.

Types of Dentition Homodont dentition: Teeth arrangement and description where an organism has teeth of the same size and shape. Fishes and birds have homodont dentition.

Heterodont dentition: where an organism has teeth of different sizes and shapes that is incisors, canines, premolars and molars. Heterodont dentition is common with mammals and reptiles. They have one root. Canines Are conical teeth with sharp pointed edges modified for seizing and tearing prey among carnivores. They have one root b. Premolar and molar They have cusps on their surface to suit their grinding action. Premolars have two roots.

Molars have either two or three roots. Classes of Holozoic Heterotrophs Holozoic heterotrophs are classified according to the type of food they consume. These are: a Herbivores: heterotrophs that exclusively feed on vegetation. Dentition of heterotrophs is based on the kind of food they consume. Dental Formula This is the of the number, type and position of teeth in the jaws of animals Number of teeth recorded represents half the total teeth in the upper and lower jaws.

The teeth names are abbreviated as a i -incisors. An animal was found to have no incisors and canines on the upper jaw. It had six premolars and four molars on the upper jaw. On the lower jaw, it had eight incisors, no canines, six premolars and six molars. Herbivores Most do not have upper incisors. Instead they have a homy pad against which grass is pressed and cut by the lower incisors. They have a long tongue that assists in the cutting and moving food.

They have a gap in the lower jaw separating canines from premolars known as diastema which allows the tongue to manipulate food. Herbivore teeth have open enamel which allows for continuous growth to replace worn out surfaces due to grinding.

Their incisors are wedge shaped to cut grass and vegetation together with the horny pad The jaws have movable joints to allow the sideways movement of lower jaw to facilitate grinding of grass. Carnivores Their incisors are chisel shaped and closely fitting to seize the prey. Their canines are long, conical and curved to hold, kill and tear the prey.

Their jaws are attached to powerful muscles that move the jaws up and down Carnivores are adapted to fast running by possessing well developed leg muscles. Dental Diseases a Dental Carries Caused by lack of hard food, too much sweet or sugary food, lack of calcium in diet, lack of vitamin D, lack of cleaning teeth and general ill-health. The bacteria in the mouth break down the sugars to form energy and organic acids. Sometimes people will extend the handle with a cheater bar or hit it with a hammer.

This type of misuse will typically void the warranty of the vise and possibly damage it. It is often warned against in the instruction manual. From Wikipedia, the free encyclopedia. Device to secure an object to be worked on.

For other uses, see Vice disambiguation and Vise disambiguation. This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.

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