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Biology Form 1 Home Notes High School --Mathematics ---Form 1 Mathematics Notes ---Form 2 Mathematical Notes ---Form 3 Mathematical Notes ---Form 4 Mathematics Notes ---Form 1 Mathematics Questions and Answers ---Form 2 Mathematics Questions and Answers ---Form 3 Mathematics Questions --- and Answers --- 3 Mathematics Questions and Answers --- --- --- 3 Mathematic ---s Savannah --A Doll's House ---The Pearl Study Guide ---Memories I Lost ---Inmoritrean Study ---Form 1 Functional Writing Notes ---Form 2 Functional Writing Notes ---Form 3 Functional Writing Notes ---Form 4 Functional Writing Notes --Kiswahili ---Tumbo Lililtoshiba na Hadithi Nyingine --- Mwongozo wa Kigogo ---Tumbo Lililtoshiba na Hadithi Nyingine ---Mwongozo wa kigogo ---Mwongo zo ---Tumbo Lililtoshiba na Hadithi Nyingine ---Mwongozo wa Kigogo --- --- <1> <0>Mwongozo wa Chozi La Heri ---Sarufi na Matumizi ya Lugha --- Isimu Jamii Notes ---Fasihi Notes ---Ushairi Notes --- Mwongozo wa Kuandika Insha -- Biology ---Biology Form 1 Notes ---Biology Form 2 Notes ---Biology Form 3 Notes ---Biology Form 4 Notes --- Biology Essays --Chemistry ---Form 1 Chemistry Notes ---Form 2 Chemistry Notes ---Form 3 Chemistry Notes ---Form 4 Chemistry Notes ---Chemistry Practice --Physics --- Physics Form 1 Notes ---Physics Form 2 Notes ---Physics Form 3 Notes ---Physics Form 4 Notes --CRE ---CRE Form 1 Notes ---CRE Form 2 Notes ---CRE Form 3 Notes ---CRE Form 4 Notes --IRE ---IRE Form 1 Notes ---IRE Form 3 2 Notes ---IRE Form 3 Notes ---IRE Form 4 Notes --Geography ---Geography Form 1 Notes ---Geography Form 2 Notes ---Geography Form 3 Notes ---Geography Form 4 Notes --History and Government ---Historical Form 1 Notes ---Historical Form 2 Notes ---Historical Form 3 Notes ---Historical Form 4 Notes --Agriculture ---Agriculture Form 1 Notes ---Agriculture Form 2 Notes ---Agriculture Form 3 Notes ---Agriculture Form 4 Notes ---Agriculture KCSE 2019 Project -- Business Studies --Business Prostheses Form 1 Notes ---Agriculture Business Studies Form 2 Notes ---Indu Business Studies Form 3 Notes ---Indu Business Studies Form 4 Notes --Computer Studies ---Computer Investments Form 1 Notes --- Computer Trials Form 2 Notes ---Computer Ingnits Form 3 Notes ---Suli Computer Studies Form 4 Notes --Home Science ---Home Science Form 1 Notes ---Home Science Form 2 Notes ---Home Science Form 3 Notes ---Home Science Form 4 Notes Past Papers --KCSE --- KCSE 2017 Reports ---KCSE 2008 ---KCSE 2019 ---KCSE 2009 ---KCSE 2010 ---KCSE 2011 ---KCSE 2012 ---KCSE 2013 ---KCSE 2014 ---KCSE 2015 ---KCSE 2016 --- <3> <4>2018 Pre-Mocks 2017 --PRE-MOCKS ---2016 ----MOKASA Pre-Mocks ----CATHOLIC DIOCEZA DE KERICHO (CDK) EXAMENE ? 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READ THE LATEST NOTES. BIOLOGY FORMA A NOTE INTRODUCTION IN BIOLOGY What is Biology? Biology is the branch of science that deals with the study of living beings. In Greek, Bios means life while Logos means knowledge. Branches of Biology There are two main branches: Botanical: Study of Plant Zoology: The study of other animals include: Ecology: The study of living beings in their surroundings. Genetics: Study of inheritance and variation. Entomology: Study of Insects Parasitology: Study of Parasites Taxonomy: Study of The Classification of Bodies Microbiology: Study of Microscopic Bodies Anatomy: Study of Cell Structure Citology: Study of Cells Biochemistry: Study of Chemical Changes within Living Organisms Name at least six other smaller branches of biology (6 marks). The Importance of Biology Solving Environmental Problems. Food shortages, services poor health, pollution, misuse of environmental resources, etc. Career choice, e.g. Medicine, Agriculture, Public Health, Veterinary, Zootehnie, Horticulture, Dentistry, etc. Acquiring scientific skills g. observation, identification, identification, classification, measurement, analysis, evaluation, etc. International cooperation g. The development of HIV\AIDS vaccine, the fight against severe acute respiratory syndrome (SARS), the fight to save the ozone layer from exhaustion, resource management through international depletion. Others Help on the study of other topics Find out which living beings are made up of and their working bodies Acquire knowledge about plant and animal diseases and their treatment. Know the effects of our bodies on the abuse of drugs and substances and you can kill. Learn more about HIV\AIDS and other viral diseases, for example, its treatment ? balanced diets, proper hygiene, spread, sexual behavior, cultural practices, etc. List five professional occupations that require the study of biology. (5 marks) Characteristics of living beings; Nutrition: The process by which living beings acquire and use nutrients: photosynthesis plants; animals feed on already manufactured food. Breathing: the process of producing energy that occurs in all cells of life. Gas exchange: if living beings take in the air (oxygen) and give air (carbon oxide iv) on the respiratory surfaces. Excretion: A process by which waste or harmful materials resulting from chemical reactions in the cells of living objects are disposed of. Excess of such materials poison living things. Growth and development: Growth -is irreversible growth in size and mass.-Essential for body function. Development ? Irreversible change in the complexity of the structure of living beings. Reproduction: The process by which living beings give birth to new people of the same kind. Irritability: It is the ability to live things to perceive changes in their surroundings and respond to them properly. For example, the reaction to changes in temperature, humidity, light, pressure and the presence of certain chemicals. Movement: Change of position either through one side or through the whole life. Locomotion ? Progressive change of position by the whole life. In animals, movement includes; swimming, walking, running, flying. In plants, closing leaves, folding leaves, closing flowers, growing shoots towards light, etc. QuestionList four uses of energy obtained from the breathing process. (4 marks). List six characteristics of life (6 marks). Collection of specimens Used device Sweep net: for catching flying insects. Fishnet: For the capture of small fish and other small water animals. Pooter: For sucking small animals from rock surfaces and bark. Bait Trap: To attract and capture small animals, e.g. rats. Fall Trap Trap: For catching crawling animals. Pair of forceps: raising small animals that crawl, for example, stinging insects. Bottles of specimens: keeping the collected specimen. larger ones require large bottles. Magnifier: Tool used to magnify objects. The lenses are found in the microscope and the lens of the hand (wolf). Its frame is marked, for example, x8 or x10 -- indicating how large the image will be compared to the object. Precautions Precautions Collecting and observing specimens Collect only the number of specimens you need. Do not harm specimens during the capture or collection exercise. Handle dangerous or harmful samples, e.g. stinging plants or insects, e.g. the use of forceps or hand gloves. The teacher will immobilize very mobile animals. (diethyl ether, formalin, chloroform) Do not destroy the natural habitat of specimens. Practical activity 2 Practical activity 3 Comparison between plants and animals Animal plants 1. Green color (have chlorophyll) 1. The lack of chlorophyll thus feeds on ready-made food. 2. Their cells have cellulose cell walls. 2. Cells lack the walls of cellulose cells. 3. Respond slowly to changes in the environment. 3. Respond quickly. 4. Lack of specialized excretory organs. 4. Have complex excretory organs. 5. Don't move. 5. Move about in search of food and water. 6. Growth takes place in the pull and root tip. (apical growth) 6.Growth occurs in all parts of the body9intercalaring growth). Review Questions CONTENTS CONCERNING INTRODUCTION Live things are also known as living organisms. Bodies (life forms) have distinctive characteristics and are therefore grouped. Magnifier -It is used for expanding small objects. (Chart) Procedure for its use Place the object on the bench. Move the lens of the hand from object to eye. You can see an enlarged image. Drawing magnification = Length of drawing/drawing Length of object/Real length (Chart) External characteristics of plants and animals External characteristics of Rhizoids plants as in moss plant. Fronda in ferns. Roots, stems, leaves, flowers, seeds, fruits, and cones in larger plants. External characteristics of animals Tentacles in hydra Feathers in birds Wings to birds Fur and hair to mammals Scales and fins in Fish Proglotide in the tapeworm of mammary glands in mammals Locomotor structures for example, limbs in insects Pigmentation of the body Practical activity 1 To collect and observe specimens of animals To collect and observe specimens of plants What is classification? -It is a field of biology that deals with the grouping of living organisms according to their structure. Bodies with similar structures are placed under a group called taxon -- taxa (plural). Groups also take into account evolutionary relationships (phylologia) -- because all living organisms had a common origin at one time. Taxonomy -- Science of classification. Taxonomist-Biologist who studies taxonomy. Classification is needed. Reasons for identifying living organisms in their correct groups for reference and study To bring together living organisms with similar characteristics, but separate those with different characteristics. To arrange information to living organisms in an orderly manner. This avoids chaos and confusion. to understand the evolutionary relationship between different organisms taxonomic units are groups (tax) in which organisms are placed as a matter of convenience. Groups are based on common observable characteristics in the group. In a (taxonomic units or groups, a hierarchy of groups are recognised from the first largest and highest group; Kingdom to the smallest and smallest unit; Species. There are 7 major taxonomic units. KINGDOM PHYLUM / DIVISION CLASS ORDINE FAMILY GEN SPECII Kingdom There are five Kingdoms of living organisms, namely: Kingdom of Monera: bacteria Protoctista Kingdom: algae, protozoa, amoeba, paramegum Kingdom Mushrooms: Moulds, Yeast, Mushrooms Kingdom Plantae: Plants moss, ferns, corn, garden peas, pine, oak meru, beans etc. Kingdom of Animalia: hydra, tapeworm, bees, human beings, etc. A kingdom is divided into Phyla into animals or divisions into plants and sorts organisms based on the plane and shape of the body. The plan is to adapt to a particular way of life. The class is divided into small groups; Commands using structural features. Orders are divided into families using structural characteristics, then Families in Genres (singular genus) ? based on recent common ancestral characteristics, which are less adaptive. The genus is divided into species, i.e. some kind of plant or animal. At the bottom of the hierarchy, the number of organisms in each group decreases, but their similarities increase. Members of the Species group naturally cross to produce fertile springs. Minor differences are manifested in species groups, for example in terms of skin color in humans and plant varieties. Groups of species are referred to as varieties, breeds or strains. Classification of a human being and a maize plant Taxonomic unit Om being corn bean kingdom Animalia plantae plantae Phylum or division Chordata AngiospermaE class Mammalia monocotyledae Dicotyledonae for Primates Graminales Rosales family Hominidae Graminaceae Leguminosae gen homo zea Phaseolus species sapiens mays Vulgaris Scientific name Homo sapiens Zea mays phaseolus vulgaris The scientific name of living organisms The present name was developed by carolus Linnaeus 18th c, where the bodies received 2 names in Latin. Living organisms shall have their scientific names and common names, namely local or vernacular names. The scientific name uses the double naming system -- the binomial system. In the binomial system, an organism is given both the name of the genus and the species. Binomial nomenclature (Double Naming System)-Is the attribution of scientific names to living organisms governed by a defined set of internationally recognised rules. The principles of binomial nomenclature The first, the name of the genus, should begin with a capital letter and the second name, the species, should begin or write in small letters, for example Lion--- Panthera leo Leopard--- Panthera pardus Domestic dog--- Canis farmiliaris Human being--Homo sapiens Porumb plant--Zea mays Lion and Leopard are closely related-- Same genus but distantly related--different species. Scientific names must be printed with in manuals and where handwritten to be underlined, for example, Panthera leo. The specific name (species) is frequently written with the name who first described and appropriately named the body, e.g. Phaseolus vulgaris, i.e. Vulgaris, is the scientist who described and named the bean plant. Biologists should give a Latinized name to a newly described animal or plant species where the Latin name is missing, for example, Meladogyne kikuyuensis - It is a scientific name of a nematode from kikuyu. Aloe kilifiensis - A member of the Aaloee family from The Discovery of Kilifi. Garinsoga parviflora waweruensis -- a member of the Macdonald eye family discovered by Waweru. Question of the study 1 Complete the table below Taxon Lion Domestic Dog Garden peas Napier grass kingdom Phylum / division class order family gen species Scientific name -------------- ---------------- --------------- ---------------- Review Questions: CLASSIFICATION 1 Review of magnification lens Calculation magnification External characteristics of plants and animals Diversity of living organisms Bodies with similar characteristics are placed under a group called taxon (taxons). The science of classification is known as taxonomy. Biologists studying taxonomy are called taxonomists. Need For Classification Helps in identifying living organisms in their correct reference groups. It brings together organisms with similar characteristics and separates those with different characteristics. Help to organize information about living organisms in an orderly manner avoiding any confusion. Helps to understand the evolutionary relationship between different living organisms. The historical context of the classification Long ago classification was artificial, where living things were classified either as plants or as animals. Plants were classified as herbs, shrubs and trees. The animals were divided into carnivores, herbivores and omnivores. Modern classification today uses evolutionary relationships between living organisms. Taxonomic classification units This refers to groups in which living organisms are placed in classification. These units start from the first largest and highest group (kingdom) to the smallest and smallest unit (species). There are seven taxonomic units, as shown below. Carolus Linnaeus (1707-1778) initially introduced the classification system for the two kingdoms. However, many new life forms have been discovered, which are neither animals nor plants. This has led to a more accepted classification system, which adopts five kingdoms. These are; ) Monera .for example, Protoctista bacteria e.g. algae and protozoa Mushrooms e.g. fungi, molds and yeast. Plant, e.g. maize, ferns and all types of trees. Animalia, e.g. humans, cow tapeworms, flies, etc. The kingdom is divided into several phyla sins into animals or divisions into plants. Phylum (phyla) or Division in plants. It is the second largest and divided into classes. Each class is divided into several orders. Orders are divided into smaller ones called families. The family is divided into several genres. Here the members are closely related. It is further divided into species. This is the smallest classification unit. The species is is is as a group of organisms whose members naturally cross to produce fertile chicks. Members of a particular species have small differences, such as skin color, height, etc. Classification of human and maize plants. (Table 2.1 Page 15 KLB Bk 1) Scientific name of living organisms. Today the bodies are given two names in Latin. This was developed by Carolus Linnaeus. Latin was used because it was widely spoken in its time. In the scientific name, an organism is given to the genus and the name of the species. This dual naming system is known as the binomial system (two system name) Binomial nomenclature. This is the system of double naming of organisms in which organisms are assigned two names, namely the generic name and the specific name. The following rules shall be observed in the binomial nomenclature. The generic name is written first followed by the specific name. The first letter with the generic name is in capital letters, and the rest is in lowercase. The specific name is written in lowercase. The two names are underlined separately when handwritten or italic when printed. Newly discovered species must be given Latinized names. The specific name is frequently written with the name of the scientist who properly described and named the organism. Examples Review Questions CELULAR PHYSIOLOGY This is the study of the functions of cellular structures. The structure of the membrane and the properties a membrane is a surface structure comprising the cell and organelles. Membranes regulate the flow of materials outside the cell or organtelle. Examples of membranes: cell membrane, tonoplast (the membrane around the cow), the nuclear membrane, the mitochondrial membrane, the chloroplast membrane, etc. The cell membrane has three layers, two layers of protein and a phos-pholipid layer sandwich between the two. Diagram Properties of semi-permeability cell membrane. ? It has small pores that allow small molecules to pass into and out of the cell. Cell Wall however allows all materials to pass through it, therefore it is referred to as permeable. Sensitivity to changes in temperature and pH - Extreme temperature and pH affect the cell membrane because it has some layers of protein. Such changes alter the membrane structure affecting its normal functioning. Possession of electrical loads - has both negative and positive charges helping the cell to detect changes in the environment. These tasks also affect how substances move in and out of cells Physiological processes The ability of the cell to control the movement of substances in and out of the cell is carried out by physiological processes, such as diffusion, osmosis and active transport. Diffusion This is a process by which particles move from a high-concentration region to a high-concentration region Practical activity 1 To demonstrate diffusion using potassium permanganate (VII) Difference in particle concentration between the high-concentration region and low concentration is known as diffusion gradient. The role of diffusion in living organisms Mineral salts in the soil enter the root by diffusion, because their concentration in the soil is higher than in the root hair cells. Digested foods (glucose and amino acids) diffuse on the wall of the ileum into the blood to be transported to the rest of the body. Gas exchange in plants and animals In both plants and animals, respiratory gases (oxygen and carbon oxide (IV)) are exchanged by simple diffusion, depending on their concentration gradient. Nitrogen waste excretion Transport of leaf-made food to other parts of plants. Factors affecting diffusion A higher diffusion gradient between two points increases the diffusion rate. Area ratio area/volume The higher the ratio, the higher the diffusion rate and the lower the ratio. This means that small organisms expose a large area to the environment compared to large organisms. Therefore, small organisms depend on diffusion as a means of transport of food, respiratory gas and waste. Charts The thickness of membranes and tissues The thicker the membrane the lower the diffusion rate, because the distance covered by the diffusion molecules is greater. The thinner the membrane, the higher the speed. The size of molecules Small and light molecules diffuse faster than large and heavy molecules. Increasing the temperature increases the energy content in molecules, causing them to move faster. Osmosis This is the process in which solvent molecules (water) move from a concentrated (diluted) solution to a highly concentrated solution on a semi-permeable membrane. Diagram fig 4.6 The highly concentrated solution is known as Hypertonic Solution. The humble concentrated solution is called hypotonic solution. It is said that the solution of the same concentration is isotonic. Osmosis is a special type of diffusion because it involves the movement of solvent molecules (water) from their high concentration region into the low concentration region in a semi permeable membrane. Practical Activity 2 Practice Activity 3 Osmotic Pressure This is the pressure to be applied to a solution to prevent the inner flow of water on a semi-permeable membrane. This is the pressure required to cancel the osmosis. Osmotic pressure is measured using osmotic potential This is the measure of pressure that a solution would develop to remove water molecules from pure water when separated by a semi-permeable membrane. Water relations in animals The cell membrane of the animal cell is semi permeable just like dialysis/visking tubes. Cytoplasm contains dissolved sugars and salts in the form of a solution. If an animal cell, e.g. a red blood cell, is placed in distilled water hypotonic), water flows through osmosis. The cell would swell and eventually burst, because the cell membrane is weak. Breakage of red blood cells when placed in hypotonic hypotonic solution called Hemolysis. If a similar red blood cell is placed in a hypertonic solution, water is extracted from the cell by osmosis. The cell will shrink through a process called Crenation. The bodily fluids around the cells must therefore have the same concentration as that found inside the cell. Charts water relationships in plants When a plant cell is placed in a hypotonic solution gains osmosis water and distends outwards. As the cell gains more water, its vats increase and exert an external pressure called turgor pressure. As more water is drawn, the cell becomes firm and rigid and is said to be turgid. The cell wall in the plant cell is rigid and prevents the cell from breaking, unlike in the case of animal cells. The cell wall develops a resistant pressure that pushes inward. This pressure is equal and opposite to the turgor pressure and is called wall pressure. Charts When a plant cell is placed in hypertonic solution, water molecules move from cell to solution through osmosis. The cell shrinks and becomes flaccid. If the cell continues to lose more water, the plasma membrane pulls away from the cell wall towards the center. The process by which plant cells lose water, shrink and become flasses called Plasmolysis can be reversed by placing a flasce cell in distilled water and this process is called Study Question 5 Practical activity 4 Wilting When plants lose water by evaporation and sweating, cells lose turgidity, shrink and droops plants. This is called If the water supply from the soil is inadequate, the plants do not recover, therefore, permanent wilting. Study Question 6 The role of osmosis in organisms Absorption of water from soil The root hair cells of plants absorb water from the soil through osmosis. The cells of herbaceous plants, which are less woody, absorb water, become turgid, therefore support. Opening and closing stomata During the day, the guard cells synthesize glucose, attract in water, become turgid, therefore open the stomata. During the night, they lose their turgosce, because there is no photosynthesis. As a result, they decrease the stomata closure. Feeding in insectivorous plants These plants are able to change their turgor pressure on the leaves that close to trap insects, which are digested to provide the plant with nitrogen. In the tubules of the kidneys, water is reabsorbed back into the body through osmosis. Factors affecting the osmosis concentration of the solutions and the concentration gradient. The higher the concentration gradient between two points, the faster the osmosis speed. Optimal temperature, as long as it does not destroy the semi-permeability of the membrane. Active transport This is the process that moves substances into cell membranes against a concentration process requires energy to move these substances into cell membranes and involves substances such as amino acids, sugar and many ions are taken by living organisms through active transport. The role of active transport Re-absorption of sugars and useful by the absorption of the kidneys of some mineral salts by the roots of plants Absorption of digested food from the food channel into the bloodstream Accumulation of substances in the body to compensate for osmotic imbalance in the arid and saline environmentRecure of waste from body cells Factors affecting active transport. Oxygen concentration. PH change. Glucose concentration. Enzyme inhibitors. NB/ Any factor affecting energy production affects the active transmission rate. Review questions. Specialization of cells, tissues, organs and organ systems This is where cells are modified to perform specific functions. They say such cells are specialized. Examples include sperm that has the tail for swimming and the root hair cell, which is expanded creating large surface for water absorption. These are cells of a certain type that are grouped together to perform the same function. Animal tissues include; Epithelial tissue ? which is a continuous thin layer of cells for lining and protecting internal and external surfaces. Skeleton ? is a bundle of elongated cells with fibers that can contract. Its contraction and relaxation bring movement. Blood tissue ? this is a fluid that contains red blood cells, white blood cells and platelets. It transports many substances and protects the body against infections. Connective tissue ? consisting of strong fibers that connect other tissues and organs that hold them together. Plant tissues include: the epidermal tissue of a plant ? this is a single layer of cells that protect the inner tissues of the plant. Palisade tissue ? this is a group of cells rich in chlorophyll. I absorb the energy of light during photosynthesis. Parenchym tissue ? it makes thin cells with irregular walls in shape. Store water and food. Vascular package ? consists of xylem and phloem. Xylem drives water and mineral salts while phloem conducts food substances. Many tissues become specialized and grouped together to perform a functional unit called the organ. Examples of organs in plants include; roots, leaves, flowers and stem. In animals these include the heart, lungs, kidneys, brain, stomach and liver. This consists of several organs whose functions are coordinated and synchronized to achieve an effective action is called an organ system. Examples include; digestive, circulatory, excretory, respiratory, reproductive and nervous systems. Review Questions MICROSCOP Microscope Parts & Functions Parts of Microscope 1. Eyepiece Contains a magnifying glass that concentrates the image from the lens into the eye. 2. Adjust course For low magnification focus 3. Fine-tuning For focus below large or minimum magnification 4. Low Power Lens For large specimens or overview 5. High Power Objective For or small specimens 6. Specimen on glass slide What do you want to look at 7. Stage Supports the specimen in the correct location of goal 8. The capacitor focuses light on specimen 9. Diaphragm (iris or Adjusts the amount of light and contrast 10. Light Source Lights the specimen for viewing The manipulation and care of the microscope the following rule must be observed: Use both hands when carrying the microscope. One hand should hold the base and the other holds the limb. Never place the microscope too close to the edge of the bank. Do not touch the mirror and lenses with your fingers. Clean dirty lenses using soft tissues. Clean other pieces using a soft cloth. Do not water any part of the microscope. Make sure that the reduced power clicks into position under the eye piece before and after use. Always keep the microscope in a safe place without dust and moisture. Using the microscope Place microscope on the bench with the scene facing away from you. Rotate the low power lens until it stops in position. Make sure the aperture is fully open. Look through the eyepiece with one eye. Adjust the mirror to make sure that the maximum light can pass. Place the slide containing the specimen on the stage and place it in position. Make sure the slide is in the center of the field of view. Look through the eyepiece again as you adjust the mirror to make sure the maximum light reaches the specimen. Use the coarse adjustment button to bring the low power lens to the lowest point. While viewing through the eyepiece, gently rotate the coarse adjustment button until the specimen is focused. Use the fine-tuning button to bring the image into clear focus. Make a drawing of what you see. For greater magnification, rotate the midpower in position and adjust the focus using the coarse button. Use the fine-tuning button for clearer focus. For even large increases, turn the high-powered lens into position. In this case, use only the fine-tuning button to bring the details into a clearer focus. Increase Magnification of the object viewed under the microscope is calculated by; Enlargement = Eye Piece Lens Enlargement X Lens Lens Enlargement Objective. If the eye lens has x5 magnification and the low power lens has an increase of x10, the total magnification is 5?10=50. Study Question 1 Fill in the table below. Eye piece lens magnification Lens lens magnification Total magnification X5 X4 X10 X10 X10 X100 X40 X600 X100 Practical activity 1 Cell structures seen under light microscope The following cellular organelles can be seen under the light microscope. Cell wall. Cell Membrane Cytoplasm Nucleus Charts- Plant Cells and Animal Electron Microscope. It's stronger than the light microscope. It can increase up to 500,000 times and has great resolution power. The high resolution power of the electron microscope allows it to separate objects that are close to each other. The electron microscope uses an electron beam instead of light to illuminate the object. Study 2 Practical activity 2 Cellular structures so seen under electron microscope diagrams - plant cells and animals Cellular organs membrane (plasma membrane). It has three layers, i.e. a layer of phospho-lipid layer caught between two layers of protein. It is flexible with pores and ahs the following main functions. Includes all cell contents. It allows the selective movement of substances in and out of the cell, as it is semi-permeable. Diagram is the fluid environment in which chemical reactions occur. It has some movements called cytoplasmic streaming. Contains organelles, starch, glycogen, fat drops and other dissolved substances. Nucleus has a double membrane called a nuclear membrane. The membrane has pores that allow materials to pass into and out of the cell. The nucleus has a fluid called a nucleoplasm in which the nucleol and chromatin are suspended. The leononelus produces ribosomes while chromatin contains the hereditary material. Mitochondria (Mitochondria) These are sausage-shaped and are respiratory sites. Mitochondria has two membranes. The inner membrane is much folded into the cristae to increase the surface for breathing. Cells that require a lot of energy have a large number of mitochondria, for example, muscle cells, sperm cells, kidney cells, etc. Endoplasmic reticulum (ER) diagram Some endoplasmic reticulum have granules called Ribosomes on their surfaces, therefore referred to as hard endoplasmic reticulum. Others do not contain ribosomes, therefore, the name of smooth endoplasmic reticulum. Hard endoplasmic reticulum transport ing proteins while smooth endoplasmic reticulum carries lipids. Charts They are spherical in shape and form the site for protein synthesis. Lysosomes They contain lithic enzymes that break down large molecules, destroy worn organelles or even the entire cell. Golgi Bodies (Golgi apparatus) Their function is to pack and carry glyco-proteins. They are also associated with the secretion of synthesized proteins and carbohydrates. Diagram They are rod-shaped structures that are used in cell division and in the formation of cilia and flagella. Plant cells lack Centrioles. They are egg-shaped and contain two membranes. The chloroplast has chlorophyll that captures the light energy to be used during photosynthesis. These are bags filled with a liquid called cell sova. Animal cells contain small vacuoles, while plant cells have large cowolas. Sap vacuoles store sugars and salts. Cow food store and digest food while contractile vacuole excrete unwanted materials from the cell. Cell Wall It is a rigid outer cover of cellulose plant cells. It gives the plant cell a defined shape while providing mechanical support and protection. The cell wall also allows water, gas and other materials to pass through it. Study Question 3 Differences between plant cells and animals Preparation of temporary blades Practical activity 3 Estimation of cell sizes. NUTRITION OF PLANTS AND ANIMALS Nutrition is the process by which organisms obtain and assimilate There are two ways of nutrition; Autotrophicsm and heterotrophicsm. Autotrophicthis This is is the living organism produces its own complex food substances from simple substances, such as carbon oxide (iv), water, light or chemical energy. If sunlight is used as an energy source, the process is referred to as photosynthesis. Photography means light while synthesis means doing. Some plants none green make their own foods using energy obtained from certain chemicals through a process called organisms that make their own foods are referred to as autotrophs. Heterotrophism This is where organisms take in complex food materials, such as carbohydrates, proteins and fats obtained from bodies of plants and animals. Bodies that feed on already manufactured food are called Heterotrophs. Autotrophic External structure of a leaf A leaf is a flattened organ that is attached to the stem or a branch of a plant. Charts Parts of a Lamina leaf: This is the flat surface. It is green in color and contains photosynthetic tissue. Midrib: This is a thick structure that runs through the middle of the leaf veins: They occur from midrib to the formation of an extensive network of veins. Apex Leaves: This is the tip of the leaf and is usually stressed. Petiole: Attach leaves to the stem or branch. In some monocotyledonous plants the leaves are attached to the stem of the leaf tea. Practical activity 1: To examine the external characteristics of a dicotyledonous and monocotyledonous leaf Question 1 The internal structure of a leaf The internal structure of the leaf is composed of the following parts. It is a waterproof and transparent thin layer that covers the upper and lower surfaces of the leaf. Reduces excessive water loss and protects the plant's inner tissue from mechanical injury. It also prevents the entry of diseases that cause microorganisms. Because it is transparent, it allows the penetration of light for photosynthesis. It is a thick tissue of a cell on both the upper and lower leaves surfaces. Secret the cuticle and protect the inner tissues from mechanical damage and prevent the entry of pathogens. Epidermal cells do not have chloroplast, except for protective cells. Watch cells are special bean-shaped cells. They have chloroplast and are able to perform photosynthesis, thus controlling the opening and closing of the stomata. The air moves in and out of the leaf through the stomata. Palisade layer. This is a layer of cells located under the upper epidermis. It is made of tightly packed cylindrical-shaped cells they have numerous chlorophyll-containing chloroplasts. Their position and arrangement allows them to receive maximum light. Spongy mesios layer. This is under the palisade layer. The cells are irregularly shaped and packed creating large air spaces between them. Air spaces allow gases to diffuse between cells. They contain fewer chloroplasts compared to palisade. Leaf veins. Each vein is a vascular package consisting of xylem and phloem. Xylem drives water and mineral salts from the roots to the leaves while transfer foods made from leaves to the rest of the plant. Study Question 2 Leaf Adaptations to Photosynthesis. Wide and flat lamina to increase the surface of carbon (IV) oxide and the absorption of sunlight. Thin transparent cuticle and upper epidermis; to allow easier penetration of light into photosynthetic cells; Thin; for faster gas diffusion; Palisad cells placed near the upper surface; to catch maximum light for photosynthesis; Palisade cells with numerous chloroplasts; to catch the maximum amount of light for photosynthesis; Large/intercellular air spaces in the spongy mesophilic layer; for the storage of carbon oxide (IV) for easier gas exchange; The cuticle resistant to ceracean water; to reduce the loss of sand water reflect excess light; Mosaic of leaves/ leaves that do not overlap; for maximum exposure to light; Guard cells, cells modified to open and close stomata; to control the amount of water loss from the leaves and allow the exchange of gases; The leaves have leaf veins; xylem to perform water to photosynthetic cells, Phloem to translocate photosynthesis products to other parts of the plant; Chloroplast They are disc-shaped organelles found in the cytoplasm of plant cells. Each chloroplast has a double membrane; inner and outer membrane. Chloroplasts are made of layers of membranes called blades contained in a fluid matrix called stroma. Several blades join to form granum (grana). Granum contains chlorophyll molecules and other photosynthetic pigments. Stroma contains enzymes that accelerate the rate of photosynthesis. Practical Activity 2: To observe the stomata distribution Study Question 3. The process of photosynthesis The raw materials for photosynthesis are; water and carbon oxide (IV). However, the process requires the presence of solar energy and chlorophyll pigment. The products of photosynthesis are glucose and oxygen. The process can be summarized using an equation as shown below. 6H2O + 6CO2 -------> C6H12O6+ 6O2 Water + Carbon (IV) glucose + oxygen oxide. The above chemical equation translates as follows: Six water molecules plus six carbon molecules (IV) Oxide produces one sugar molecule plus six oxygen molecules The photosynthesis process is nevertheless more complex than that shown in the above equation and can be divided into two stages; Light and dark light stage (Light Dependence stage) - Appears in the grain containing chlorophyll that traps / absorbs the energy of sunlight. ? This energy is used to divide water molecules into hydrogen ions and oxygen gas. ? This process is called water photolysis and is shown below. 2H2O 4H + O2 (Water) Hydrogen atom oxygen ? Hydrogen atoms produced here enter the dark stage. ? Oxygen gas removed by stomata or is used for breathing inside the plant; ? Some light is used in the formation of Adenosine Triphosphate (ATP); ATP an energy-rich compound. ? ATP is used later in the dark phase. Dark scene. (Light Independent Stage) ? Carbon oxide (IV) combines with hydrogen hydrogen atoms form glucose / simple carbohydrates. ? This is called carbon (IV) fixing oxide. Carbon (IV) Oxide + Hydrogen Atom Simple Carbohydrates CO2 + 4H C6H12O6 - This stage takes place in the stroma and proceeds whether light is present or not. - ATP Energy from the light stage is used to provide the necessary energy in this reaction; ? Simple formed sugars are used for breathing to provide energy or are converted into storable forms, e.g. lipids, proteins, starch, cellulose, etc. Study Question 4 Practical activity 3: To investigate the presence of starch in a leaf. Study question 5 Factors that affect the rate of photosynthesis light intensity. Increasing the intensity of light increases the rate of photosynthesis to a certain level where it slows down and eventually levels off. The very bright sun can damage plant tissues due to the large amount of ultraviolet light. The quality of light or the wavelength of light also affects the rate of photosynthesis. Red and blue wavelengths of light are required for photosynthesis by most plants. Optimal light intensity range Light intensity Carbon oxide concentration (IV) Increased carbon oxide concentration (IV) increases the rate of linear photosynthesis to a certain level, after which it slows down and levels off. Optimal concentration range of CO2 Carbon oxide concentration (IV) Photosynthesis temperature is a controlled process of enzymes, therefore the temperature increase increases the rate of photosynthesis to the optimum temperature. The increase in temperature beyond optimal decreases the rate sharply as the enzymes become distorted. Water plants need water for photosynthesis. Hydrogen atoms required in the dark state during carbon oxide (IV) fixation are derived from water during photolysis. Study Question 6 Practical Activity 4: To investigate the factors necessary for photosynthesis. Study Question 7 Study Question 8 Study Question 9 Study Question 10 Practical Activity 5: Investigating gas produced during photosynthesis. Study Question Question 11 Chemical compounds that constitute living organisms Cells, tissues and organs are made of chemicals that are called chemicals of life. The study of chemical compounds found in living organisms and the reactions in which they participate is called Biochemistry. Life chemicals include carbohydrates, lipids and proteins. They are compounds of carbon, hydrogen and oxygen in the ratio of 1:2:1, respectively. Carbohydrates have a general formula of (CH2O)n where n represents the number of carbon atoms in a molecule of carbohydrates. Carbohydrates are divided into three groups; Monosaccharides, Disaccharides and Polysaccharides. They are the simplest carbohydrates and have a general chemical formula of (CH2O)n where n = 6. Their chemical formula is therefore C6H12O6. These glucose, fructose, galactose, etc. Properties of monosaccharides These are water soluble to form sweet tasting solutions. They're crystallized. They have the property of reducing where they reduce copper in benedicts red copper solution (I) oxide. Functions They are oxidized to release energy during breathing. When condensed together, they form polysaccharides, such as starch, cellulose or glycogen. ii) Disaccharides They are formed by binding two monosaccharide molecules through the condensation process where a water molecule is released. Monosaccharides condensation + Monosaccharides Disaccharides + Water. C6H12O6 + C6H12O6 C6H22O11 + H2O Examples glucose + glucose maltose + water. Glucose + Fructose Sugar + Glucose Water + Galactose Galactose + Water. The type of disaccharide formed depends on the monosaccharide units that condense together. Properties of Disaccharides i) Solubil in water to form sweet tasting solutions ii) These are non reducing sugars. Some, would be maltose can reduce copper sulfate in Benedict's solution when heated together and are therefore referred to as complex reduction sugars. iii) They are easily broken into their constituent monosaccharide molecules in a process known as Hydrolysis in the presence of water. Disaccharide Hydrolysis + Water Monosaccharide + Monosaccharide C6H22O11 + H2O Hydrolysis C6H12O6 + C6H12O6 Sugar + Water Hydrolysis Glucose + Fructose Lactose + Glucose Water Hydrolysis + Galactose Galactose + Water Hydrolysis . Glucose + Glucose. Naturally, the deposits are hydrolyzed by enzymes. In the laboratory, hydrolysis is achieved by boiling them in diluted hydrochloric acid. Functions They are hydrolyzed by enzymes in monosaccharides, which are then oxidized to produce energy. iii) Polysaccharides.They are made of many monosaccharide molecules, therefore they are long and more complex. They have a general formula of (C6H10O5) n; where the value of n is a very large number. Examples of polysaccharides It is present as food stored in plant tissues, e.g. corn, wheat, potatoes, rice, etc. This is the component of the cell wall of plants. Cellulose gives plant cells their defined shape. Glycogen This is the form in which carbohydrates are stored in animal tissues. Excess glucose is converted into glycogen for storage in the liver. The properties of polysaccharides are all insoluble in water. Do not have a sweet taste, therefore are referred to as non-sugars. Study Question 12 Practical activity 6: To perform dietary tests for carbohydrates i) Starch ii) Reducing sugars iii) Non Reducing sugars These are fats and oils. Fats are found in animals while oils are found in plants. Oils are liquid while fats are solid at room temperature. They contain carbon, hydrogen and oxygen just like carbohydrates. However, they contain less oxygen atoms than in carbohydrates. Lipids are made up of three fatty acid molecules and a molecule of the nature of a lipid formed, depending on the fatty acids it contains. Glycerol remains in all lipids. The complex lipid diagram are formed by condensing many lipid molecules as in carbohydrates. Examples of complex lipids include; Phospholipid Phospholipids steroids and cholesterol. The presence of lipids in a food sample is detected by the fat stain test or the emulsion test. Properties of lipids When fats are heated they turn into liquid while oils solidify at low temperature. Both fats and oils are insoluble in water. However, they dissolve in organic solvents, would be alcohol, to form emulsions and suspensions. Lipids are inert, therefore, can be stored in the tissues of organisms. Lipid functions They give almost twice as much energy as monosaccharides. Metabolic water source When oxidized, lipids release more water than monosaccharides. Such water is called metabolic water. Structural compounds Lipids are components of the plasma membrane and protoplasm. Fats are stored under the skin of animals that form fat tissue that acts as a thermal insulator. Mammals in temperate regions have thick adipose tissue to greatly reduce heat loss. Thick fat tissue in aquatic animals helps them to be floating in water. Fat is deposited around major organs, such as kidneys, heart, etc. where they act as a shock absorber. Wax from plant cuticles reduces excessive water loss. Study Question 13 Practical activity 7: testing the presence of lipids i) Fat point ii) Emulsion protein test as carbohydrates and lipids, proteins are carbon, hydrogen and oxygen compounds. In addition, they contain nitrogen and sometimes phosphorus and sulfur. Some proteins, would be hemoglobin, contain other elements, would be iron. Proteins are made up of small units called amino acids. There are about 20 different types of amino acids. All amino acids contain the amino group (-NH2) consisting of hydrogen and nitrogen. Two amino acids combine to form a dipeptide molecule through the condensation process. The bond between two amino acids is called peptide Bond. Many amino acids come together to form a long chain of proteins called the polypeptide chain. The type and sequence of amino acids contained in such a chain determines the uniqueness of the formed protein. Protein properties They dissolve in water to form colloidal suspensions (not true solutions) if the particles remain suspended in water. They are distorted by temperatures above 40 0 Heat alters the structure of the protein molecule. Chemicals, such as detergents, acids, bases and organic solvents, also distort proteins. They are amphoteric by which they have both acidic and basic properties. This property allows them to combine with non-protein compounds to form conjugated proteins, such as mucus and hemoglobin. In mucus the non-protein compound is a carbohydrate while in hemoglobin, iron is a non protein. Functions of Proteins Structural Functions Proteins make the framework of living systems, for plasma membrane, connective tissues, muscle fibers, hair, nails, hooves, skeletal materials, etc. Metabolic regulators These are divided into two enzymes are organic catalysts that accelerate the rate of metabolic reactions, would be photosynthesis, digestion, etc. They are chemical messengers that regulate many processes of the body, such as growth, reproduction, amount of sugars, salts and water in the blood, etc. Energy source Under extreme hunger, proteins are broken down to release energy. Study Question 14 Practice Activity 8 To test for protein enzymes These are organic catalysts that are proteins in nature. They accelerate or slow the rate of chemical reactions in the body without being used themselves upwards. They are divided into two; Extracellular enzymes are produced inside cells, but are used outside the cells that produce them, for example, digestive enzymes. They are secreted and used in the cells that produce them, for example, respiratory enzymes. Name of enzyme There are two methods of naming enzymes; Enzymes are given to the names of the people who discovered them. The name ends in -in, such as pepsin, trypsin ptyalin etc. This is the modern method of naming. The suffix ?ase is added to the substrate (food type) or the reaction catalyzes the enzyme. Example 1 Substrate Enzyme Carbohydrates Carbohydrase Amidon for example, amylase Zaharosis Sugar Sucrose Sucrase Maltose Maltase Protein Protease Lipid Lipase Example 2 Reaction Enzyme Hydrolysis Hydrolase Oxidation Reduces Reductase Properties of enzymes These are proteins in nature, therefore are affected by changes in temperature and pH. They are specific to the substrate. They are effective in small amounts because they are not affected by the reactions they catalyze. They can be used again and again. These are catalysts that accelerate the rate of cellular reactions and are not used until the reactions they catalyze. Most enzyme-controlled reactions are reversible. Factors that affect the rate of enzymes controlled reactions Temperature Enzymes are sensitive to changes in temperature and pH because they are proteins in nature. Enzymes work best in a narrow temperature range called optimal temperature. Above the optimum temperature, the reaction decreases sharply as the enzymes are distorted. Most enzymes have optimal temperature between 35-40o Very low temperature inactivates enzymes, therefore lowering the reaction rate. PH charts Most enzymes have a pH of almost 7. Some however work best in acidic pH, for example, pepsin while others work best in alkaline conditions. As the pH changes from the optimal level, the enzyme activity decreases. Extreme acidity or alkalinity distorts most enzymes. Charts Specificity Enzymes are specific in nature where a particular enzyme acts on a specific substrate. For example, sucrose works on sucrose and not on any other substrate. Substrate concentration and enzyme concentration. When the concentration increase, the enzyme reaction rate also increases to a certain level. Subsequent growth does not increase the reaction rate, because all active places of an enzyme are occupied. When enzyme molecules are increased, the reaction rate increases proportionally. Enzyme Diagrams Co-factors and and Co-factors are non-protein substances that activate enzymes. These are needed in small quantities and include metal ions, such as iron, magnesium, zinc, copper, etc. Some are vitamins. Coenzymes are non-protein molecules that work in association with certain enzymes. Most co-enzymes are derived from vitamins. Enzyme inhibitors compete with the normal substrate for active sites and permanently occupy the active site of the enzyme. There are two types of inhibitors; a) Competitive inhibitors These are chemicals closely related to the normal substrate and compete for active sites with the normal substrate. Slow down the reaction rate. b) Uncompetitive inhibitors They do not compete with the substrate. They combine permanently with enzyme molecules, thus blocking active places. These include poisons, such as cyanide, mercury and silver-arsenic compounds. The importance of enzymes Enzymes accelerates the rate of cellular reactions and also controls them. In this way, they help prevent violent reactions in cells. Cells.

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