Grade 10 Biology Nutrition in Plants & Animals PDF

/ Kuala Lumpur, Malaysia SEMESTER I NAME: _______________________ REF: 2024-25/ BIO /STD 10/ HO1 CLASS: _______________ SUBJECT: Biology DATE:...

/ Kuala Lumpur, Malaysia SEMESTER I NAME: _______________________ REF: 2024-25/ BIO /STD 10/ HO1 CLASS: _______________ SUBJECT: Biology DATE: 8/03/2024 Topic: Nutrition in Plants & Animals Introduction The most important criterion to decide whether something is alive or not is the movement. Animals can move from one place to another or they can move their body parts whereas plants can only move parts of their body such as leaves, flowers, roots and shoots. Molecular movements which are not visible to our eyes are the various life processes happening in a living thing which keeps an organism alive. Viruses do not show any molecular movement in them (until they infect some cell) and that is partly why there is a controversy about whether they are truly alive or not. Life Processes The basic functions performed by living organisms to maintain their life on this Earth are called life processes. Basic life processes common to all living organisms are: Basic life processes Function Nutrition Nutrition is the process of taking in food and converting it into energy and other vital nutrients required for life. Respiration The process which releases energy from the food absorbed by the body. Transport The process in which a substance absorbed or made in one part of the body is moved to other parts of the body. Page 1 of 16 Copyright © Global Indian International School  Excretion The process in which the waste materials produced in the cells of the body are removed from the body. Control and coordination A process which helps the living organisms to survive in the changing environment around them. Growth The process involves the changes from a smaller organism to a bigger organism. Movement The organism either moves from one place to another or moves its body parts. Reproduction The process involves the making of more organisms form the existing ones. All the living organisms need energy to perform various life processes. They get this energy from food. Food is a kind of fuel which provides energy to all the living organisms. Try these text questions. Nutrition Need for Nutrition: Organisms need the energy to perform various activities. The energy is supplied by the nutrients. Organisms need various raw materials for growth and repair. These raw materials are provided by nutrients. Nutrients: A nutrient can be defined as a substance which an organism obtains from its surroundings and uses it as a source of energy and for the biosynthesis of its body constituents. Example: carbohydrates and fats are the nutrients which are used by the organism mainly as a source of energy. Proteins and mineral salts are nutrients used by organism for the biosynthesis of its body constituents like skin, blood, etc. Modes of Nutrition: Modes of nutrition means methods of obtaining food by an organism. There are mainly two modes of nutrition: Page 2 of 16 Copyright © Global Indian International School  1. Autotrophic mode of nutrition 2. Heterotrophic mode of nutrition Autotrophic mode of nutrition: (‘auto’ means ‘self’ and ‘trophe’ means ‘nutrition’) Autotrophic nutrition is that mode of nutrition in which an organism makes (or synthesizes) its own food from the simple inorganic materials like carbon dioxide and water present in the surroundings (with the help of energy). Those organisms which can make their own food from carbon dioxide and water are called autotrophs. Example: all green plants, autotrophic bacteria. Autotrophic nutrition is divided into two types based on the energy source used to synthesize food: 1. Photosynthetic nutrition: Seen in green plants, they use solar energy, simple inorganic substances like carbon dioxide and water to form simple sugars. The process is called photosynthesis. Such organisms are called photoautotrophs. 2. Chemosynthetic nutrition: Chemosynthesis occurs in bacteria and other organisms and involves the use of energy released by inorganic chemical reactions to produce food. Extra information However different species use different pathways. For example, at hydrothermal vents, vent bacteria oxidize hydrogen sulfide, add carbon dioxide and oxygen, and produce sugar, sulfur, and water. Other bacteria make organic matter by reducing sulfide or oxidizing methane. Chemo autotrophs are found in hostile environments such as deep-sea vents where light cannot reach. Heterotrophic mode of nutrition: (‘heteros’ means ‘others’ and ‘trophe’ means ‘nutrition’) Heterotrophic nutrition is that mode of nutrition in which an organism cannot make (or synthesize) its own food from simple inorganic materials like carbon dioxide and water and depends on other organisms for its food. Those organisms which cannot make their own food are called heterotrophs. Example: all the animals (man, dog, cat, lion, etc.), most bacteria and fungi. Page 3 of 16 Copyright © Global Indian International School Types of Heterotrophic Nutrition: 1. Saprotrophic (saprophytic) nutrition 2. Parasitic nutrition 3. Holozoic nutrition Saprotrophic nutrition: Saprotrophic nutrition is that nutrition in which an organism obtains its food from decaying organic matter like dead plants, dead animals and rotten bread, etc. These organisms show extracellular digestion. They secrete enzymes on the decaying matter and break down the complex substances into simpler ones that can be absorbed. The organisms showing saprotrophic mode of nutrition are called saprophytes. Example: Fungi (like bread mould, mushrooms), and many bacteria. Bread mould Mushroom growing on dead organic matter Parasitic nutrition: Parasitic nutrition is that nutrition in which an organism derives its food from the body of another living organism without killing it. A parasite is an organism (plant or animal) which feed on another living organism called its host. Example: some animals like Plasmodium (malarial Page 4 of 16 Copyright © Global Indian International School  parasite) and roundworms, a few plants like Cuscuta (Amarbel) and several fungi and bacteria. Parasites usually harm the host by spreading diseases. Types of Parasites: 1. Endoparasites: those that live inside the body of the host like liver fluke and tapeworm. 2. Ectoparasite: Live on the outer surface of the host like ticks, mites, leeches. 3. Obligate Parasites: live parasitically all the time. Eg. Phytopthora a fungus which causes potato blight disease. 4. Facultative Parasites: feed parasitically or saprophytically, eg. Candida fungus. 5. Parasitic plants like Dodder/Cuscuta/ Amarbel, lack chlorophyll, have no leaves, roots are modified into haustoria which penetrate into the host and draws nutrition from their vascular system. They are Total parasites as they are completely dependent on host for nutrition. 6. Viscum album or mistletoe is a partial parasite. It is capable of photosynthesizing and draws water and minerals from the host plant. Holozoic nutrition: The holozoic nutrition is that nutrition in which an organism takes the complex organic food materials into its body by the process of ingestion, the ingested food is digested and then absorbed into the body of the organism. The absorbed food is then assimilated or utilized for various life processes. The undigested food is finally removed from the body by the process of egestion. Example: human beings and most of the animals. Nutrition in Plants: Green plants are autotrophs The process, by which green plants make their own food from carbon dioxide and water by using sunlight as energy in the presence of chlorophyll, is called photosynthesis. Page 5 of 16 Copyright © Global Indian International School  Oxygen is released during photosynthesis. The process of photosynthesis takes place in the green leaves of a plant. Site of photosynthesis: chloroplast The food is prepared by the green leaves of a plant in the form of a simple sugar called glucose. The extra glucose is stored as starch. This starch is stored in the leaves, flowers, fruits and stem of the plant. The green plants convert energy of the sun into chemical energy by making carbohydrates. Photosynthesis takes place in the following three steps: 1. Absorption of radiant Sun’s energy by chlorophyll. 2. Conversion of light energy into chemical energy and splitting of water into hydrogen and oxygen by light energy (Photolysis of water). 3. Reduction of carbon dioxide by hydrogen to form carbohydrate like glucose by utilizing the chemical energy. Conditions necessary for photosynthesis: The conditions necessary for photosynthesis to take place are: 1. Sunlight: Source of energy. 2. Chlorophyll: The green pigment chlorophyll that traps Sun’s energy. 3. Carbon dioxide and water are the raw materials required for photosynthesis. Cross section of leaf Page 6 of 16 Copyright © Global Indian International School How the plants obtain carbon dioxide? There are a large number of tiny pores called stomata on the surface of the leaves of plants through which gaseous exchange and transpiration occur. The carbon dioxide gas enters the leaves of the plant through the stomata present on their lower surface. Each stomatal pore is surrounded by a pair of guard cells. Guard cells are specialized epidermal cells which are kidney shaped in dicots and dumb-bell shaped in monocots. The wall of the guard cell surrounding the pore is thickened and inelastic as compared to the rest of the cell wall of guard cells. Guard cells contain cytoplasmic lining, central vacuole, nucleus and chloroplast. The guard cells are surrounded by modified epidermal cells called subsidiary cells which support the movement of the guard cells. The opening and closing of stomatal pores are controlled by the guard cells. How Do Guard Cells Function? Guard cells are cells surrounding each stoma. They help to regulate the rate of excahnge of gases during photosynthesis and transpiration by opening and closing the stomata. Notice that in figure A, the guard cells are turgid, or swollen, and the stomatal opening is large. This turgidity is caused by the accumulation of K+ (potassium ions) in the guard Page 7 of 16 Copyright © Global Indian International School cells. As K+ levels increase in the guard cells, the water potential of the guard cells drops, and water enters the vacuole of guard cells. In figure B, the guard cells have lost water, which causes the cells to become flaccid and the stomatal opening to close. This may occur when the plant has lost an excessive amount of water. In addition, it generally occurs daily as light levels drop and the use of CO2 in photosynthesis decreases. Extra information: 1. Stomata is not present in Algae and fungi as well as in submerged plants. 2. In xerophytes and gymnosperms stomata is embedded deeply in the leaves to protect them from direct sunlight and check excessive transpiration. These are called sunken stomata. 1. In monocot leaves stomata is equally distributed on the upper and lower surface, while in dicot it is more in the lower surface. How do plants obtain water for photosynthesis? The water required by the plants for photosynthesis is absorbed by the root of the plants from the soil through the process of osmosis. As water is absorbed it creates sufficient root pressure to push the sap up into the xylem vessels to a certain height. Root pressure is effective in transport of water at night in plants. In the daytime water moves up the plant, enters the leaves, moves into air spaces in the leaf, and then evaporates through the stomata (transpiration). Water moves through the stem xylem as a column, due to the narrow diameter of the xylem, the adhesion force between water and xylem walls and cohesion force between water molecules (capillary force) help water to move like beads in a string upward to fill the vacuum created by transpiration. This suction force created by transpiration, pulls the water molecules to fill up the space created by loss of water through the stomata. Thus, water is absorbed by the roots along with the minerals from soil. Salts of nitrogen like nitrites and nitrates are absorbed by plants from soil or taken up as organic compounds which have been prepared by bacteria from atmospheric nitrogen. Nitrogen in these forms used by Page 8 of 16 Copyright © Global Indian International School  plants for protein and nucleic acid synthesis. Magnesium for Chlorophyll formation, Manganese for photolysis of water, zinc for leaf formation. So, we conclude that sap ascends up to the leaf due to the root pressure, transpiration pull along with capillary force created due to adhesion and cohesion property of water. Extra Information Root pressure is a force generated in the roots that help in driving the sap form the soil up into the plant vascular tissue. This force is caused by the osmotic pressure in the cells of the root. Root pressure is highest in rainy season when transpiration rate is low. Root pressure leads to guttation, loss of water as droplets through the pores along the margin of the leaves where the main vein ends. These pores are called hydathodes. Adhesion is the force of attraction between different substances like water and xylem wall. Cohesion is the force of attraction between molecules of the same substance Transpiration pull: As water molecules get pulled due to the tendency of water molecules to remain joined(Cohesion) during transpiration, a continuous column of water is maintained through the stem. Movement of Water Up Xylem Vessels Site of photosynthesis: Chloroplasts The site of photosynthesis in a cell of the leaf are chloroplasts which contain the green pigment chlorophyll. Chloroplasts are present in the photosynthetic cells (mesophyll cells) of green plants. These cells contain more chloroplasts than other plant cells. Page 9 of 16 Copyright © Global Indian International School Extra information Structure of Chloroplast: It is an organelle covered by a double membrane. They are filled with colourless ground substance called stroma or matrix. It contains ribosomes, starch granules, lipids, circular DNA and the thylakoids. Thylakoid: In the stroma, flattened sac like structures are present called as thylakoids. Chlorophyll pigment is found on the walls of the thylakoid. Chlorophyll-a and Chlorophyll- b are the most important pigments which are involved in the process of photosynthesis. The thylakoids pile up to form the granum. The grana are held in position by stromal lamellae. Mechanism of Photosynthesis There are two phases in photosynthesis. Light Reaction Occurs in the thylakoids of the chloroplast. Excitation of chlorophyll: On exposure to sunlight chlorophyll molecules in thylakoids absorb sunlight and become activated. Photolysis: Water molecules are split using the energy from the sunlight. Production of Energy rich molecule: The energy released during photolysis is used to produce energy rich molecule ATP from ADP by adding one molecule of inorganic phosphate(iP) Production of the reducing power: Photolysis of water produces H+ ions. It is picked by NADP (Nicotinamide dinucleotide phosphate), and NADPH another energy rich molecule with reducing power is formed. O2 is released as a byproduct. Dark Reaction/Calvin- Benson Cycle/ Light Independent Reaction: Occurs in the stroma of the chloroplast. Sunlight is not required. Page 10 of 16 Copyright © Global Indian International School  In this phase CO2 is reduced to carbohydrates with the help of the H + ions from NADPH and energy stored in ATP molecules is used. 6 turns of Calvin Cycle lead to formation of one molecule of glucose. Photosynthesis Reaction An overall chemical reaction involved in the process of photosynthesis is: 6CO2 + 12H2O + sunlight → C6H12O6 + 6O2 + 6H2O Translocation is the movement of food/glucose and also amino acids and other substances from leaves to other parts of the plant. Mechanism of Translocation It takes place in phloem tissues in plant. The movement of food in plants is bidirectional and takes place in sieve tubes with the help of companion cells. Ascent of sap takes place by simple physical forces but translocation in phloem is achieved by utilizing energy. Materials like sucrose that is formed in the leaf is transferred into the phloem using energy from ATP. This increases the osmotic pressure of the tissue. Water from the neighboring xylem move into the sieve tubes via companion cells. Page 11 of 16 Copyright © Global Indian International School  The bulk pressure increases in the sieve tubes and materials move in the phloem to tissues which have less pressure. This allows phloem to move materials in both directions, upward and downwards, from source to sink. Once sucrose reaches the sink it can be converted to glucose, which is oxidized in the cells to produce energy required for growth and reproduction. Sometimes sucrose may be stored as starch in fruits, stem, leaves and roots. Leaf adaptation for photosynthesis Large surface area to absorb maximum sunlight. Leaf arrangement on the stem is done in such a way to expose maximum surface to the sunlight. Chloroplasts are concentrated near the upper surface of leaf to trap maximum sunlight quickly. Presence of numerous stomata that allows gaseous exchange. Thin leaves that enhance rapid transport of materials between adjoining cells. Network of veins help to transport materials to and fro from the mesophyll cells of leaves. Factors Affecting Photosynthesis: Light Intensity: An increased light intensity leads to a high rate of photosynthesis and a low light intensity would mean low rate of photosynthesis. Concentration of CO2: Higher carbon dioxide concentration increases the rate of photosynthesis. Normally the carbon dioxide concentration of 0.03 to 0.04 percent is sufficient for photosynthesis. Temperature: An efficient photosynthesis requires an optimum temperature range between 25 to 35oC. Water: Water is an essential factor for photosynthesis. The lack of water also leads to a problem for carbon dioxide intake. If water is scarce, the leaves refuse to open their stomata to keep water they have stored inside. Polluted Atmosphere: The pollutants and gases settle on leaves and block the stomata, making it difficult to take in carbon dioxide. A polluted atmosphere can lead to a 15 percent decrease in the rate of photosynthesis. Page 12 of 16 Copyright © Global Indian International School Extra information The chlorophyll absorbs blue, and red-light rays. Photosynthesis occurs more in blue and red-light rays and less, or not at all, in green light rays. Chlorophyll looks green because it absorbs red and blue light, making these colours unavailable to be seen by our eyes. It is the green light, which is not absorbed that finally reaches our eyes, making the chlorophyll appear green. Nutrition in Animals (Holozoic Nutrition) Animals are heterotrophs and hence they depend on other organisms (plants and other animals) for their food. All the animals can be divided into three groups on the basis of their food habits. These are: 1. Herbivores 2. Carnivores 3. Omnivores Herbivores: Those animals which eat only plants are called herbivores. Examples are Goat, Cow, and Deer etc. Carnivores: Those animals which eat only other animals as food are called carnivores. Examples are Lion, Tiger, and Lizard etc. Omnivores: Those animals which eat both, plants and animals are called omnivores. Examples are Man, Dog and Crow etc. It is the energy of sun which provides food for plants, and animals. Different steps in the process of holozoic nutrition in animals There are five steps in the process of nutrition in animals. 1. Ingestion: The process of taking food into the body is called ingestion. 2. Digestion: the process in which the food containing large, insoluble molecules is broken down into small, water-soluble molecules is called digestion. 3. Absorption: The process in which the digested food passes through the intestinal wall into blood stream is called absorption. Page 13 of 16 Copyright © Global Indian International School  4. Assimilation: The process in which the absorbed food is taken in by the body cells and used for energy, growth and repair is called assimilation. 5. Egestion: The process in which the undigested food is removed from the body is called egestion. Nutrition in Simple Animals: Amoeba and Paramecium are two very simple unicellular animals. In unicellular animals, all the processes of nutrition are performed by the single cell. Nutrition in Amoeba: Amoeba eats tiny plants and animals as food which floats in water in which it lives. The mode of nutrition in Amoeba is holozoic. The process of obtaining food by Amoeba is called phagocytosis. Steps involved in the nutrition of Amoeba: Ingestion: Amoeba ingests food by forming temporary finger-like projections called pseudopodia around it. The food is engulfed (Circumvallation) along with a little surrounding water to form a food vacuole (‘temporary stomach’) inside the Amoeba. Digestion: In Amoeba, food is digested in the food vacuole by digestive enzymes which break down the food into small and soluble molecules by chemical reactions. Absorption: The digested simple and soluble substances pass out of food vacuole into the cytoplasm of Amoeba. Assimilation: The absorbed food materials are used to obtain energy through respiration and make the parts of Amoeba cell which leads to the growth of Amoeba. Page 14 of 16 Copyright © Global Indian International School Egestion: The remaining undigested material is moved to the surface of the cell and thrown out of the body of Amoeba by exocytosis. Nutrition in Paramecium: Paramecium is also a tiny unicellular animal which lives in water. Ingestion: Paramecium uses its hair like structures called cilia to sweep the food particles from water and put them into mouth. Ingestion is followed by other steps such as digestion, absorption, assimilation and egestion. (as written in Amoeba) Practice Questions 1. What are the differences between autotrophic and heterotrophic nutrition? 2. Where do plants get each of the raw materials required for photosynthesis? 3. If no apparent work is not being done by an organism, why does it take food? 4. How does nutrition in a fungus different from that in a tapeworm? 5. What are the end products of photosynthesis? 6. Differentiate between saprophytic and parasitic mode of nutrition based on the type of food and manner of obtaining it. 7. How do plants exchange gases? (2) 8. How does nutrition take place in Amoeba? How is it different in Paramecium? Page 15 of 16 Copyright © Global Indian International School  9. What are the outside raw materials used by an organism? 10. What is the difference between xylem and phloem. Videolinks https://youtu.be/ImMF6XKyAFM Life Processes intro https://youtu.be/SBZfM0GuNmw?si=Cy75GYnIFOiF8c6v Types of Nutrition https://youtu.be/hZAxvlXDiqA?si=SuW_qZHtL9O0RgKj Translocation https://youtu.be/d60lqIfGeQw?si=OsfPJDd84NRH6NRt Transportation of water Page 16 of 16 Copyright © Global Indian International School