Life Processes.pdf

1 CHAPTER Life Processes  NCERT Corner 1. Why is diffusion insufficient to meet the oxygen Heterotrophic Autotrophic requirements of multicellular organisms like nutrition nutrition...

1 CHAPTER Life Processes  NCERT Corner 1. Why is diffusion insufficient to meet the oxygen Heterotrophic Autotrophic requirements of multicellular organisms like nutrition nutrition humans? (i) Organisms cannot Organisms use Ans. In multicellular organisms such as humans, all make their own simple inorganic the body cells are not in direct contact with the food from simple materials like carbon external environment. Therefore, every cell of the inorganic matter dioxide and water body will not get enough oxygen as per need by and depend on and synthesise their the process of diffusion as it is a slow process. other organisms for food in presence of their food. sunlight. 2. What criteria do we use to decide whether (ii) All the animals, All green plants something is alive? most bacteria and and some algae Ans. Living organisms carry out metabolism to maintain fungi shows this shows this mode of their ordered structures by acquiring energy and mode of nutrition. nutrition. matter from the surrounding. 6. Where do plants get raw materials required for 3. What are outside raw materials used by an the process of photosynthesis ?  (CBSE 2020) organism ? Ans. Ans. Energy is required by all living species, to sustain and (i) Carbon dioxide: It is obtained from atmosphere. preserve their existence. (ii) Plants absorb water from the soil through roots and transport to leaves. Oxygen, water, and food are examples of external raw (iii) Sunlight: Sunlight comes from the sun. materials used by organisms. (iv) Chlorophyll: It is present in chloroplast found in Plants obtain their raw materials from the environment green plants. in the form of carbon dioxide, water, and sunlight. 7. What is the role of the acid in our stomach ? These are used to synthesize their food in the presence Ans. Role of acid in the stomach is : of chlorophyll, a green color pigment. (i) To kill harmful bacteria that enter with food in body. Animals use basic materials in the form of food, (ii) To make acidic medium which is required for the water, and oxygen from the environment. activation of the enzyme pepsin. (iii) It also helping digestion of proteins. 4. What processes would you consider essential for maintaining life ? 8. What is the function of digestive enzymes ? Ans. The food we eat is very complex in nature, because Ans. The maintenance function of living organisms it comprises of complex molecules. Digestive must go on even when they are not doing anything enzymes break down these complex molecules particular. The various processes essential into smaller simpler molecules, so that they can for maintaining life are nutrition, respiration, be easily absorbed by the walls of the intestine. transportation, excretion, control and coordination. 9. How is the small intestine designed to absorb In absence of any one of these, the life become, digested food ? difficult. Ans. The small intestine has folds which increase 5. What are the differences between autotrophic surface area. These folds have finger-like projections known as villi which further increases nutrition and heterotrophic nutrition? surface area. The villi consist of many blood Ans. Differences between autotrophic and heterotrophic vessels which takes the absorbed food to each and nutrition are as follows: every cell of the body. 2 UDAAN Study Material Class-X PW  10. What advantage over an aquatic organism 13. How is food transported in plants? does a terrestrial organism have with regard Ans. The movement of food in phloem (or translocation) to obtaining oxygen for respiration? occurs by using energy. Food (sugar) made in Ans. Aquatic organisms use oxygen dissolved in leaves is loaded into the sieve tubes of phloem surrounding water. Since, air dissolved in water tissue by utilizing energy from ATP. Now, water has fairly low concentration of oxygen, the aquatic enters the sieve tubes containing sugar by the organisms need to have higher rate of breathing. process of osmosis. Because of this, the pressure Terrestrial organisms acquire oxygen from the in the phloem tissue increases. This high pressure oxygen-rich atmosphere through respiratory generated in the phloem tissue moves the food to organs. Hence, can work less with breathing rate all parts of the plant having less pressure in their than aquatic organisms. tissues. This help the phloem to transport food 11. What are the different ways in which glucose is according to the requirement of the plant. oxidised to provide energy in various organisms? 14. How is oxygen and carbon dioxide transported Ans. The first step of breakdown of glucose (6 carbon in human beings? molecule) occurs in the cytoplasm of cells of all Ans. the organisms. This process yields a three carbon (i) Transport of carbon dioxide: Carbon dioxide molecule compound known as pyruvate. is more soluble in water as compared to oxygen. Further, breakdown of pyruvate takes place in Therefore, it is mostly transported from body many distinct ways in different organisms. tissues in dissolved form in our blood plasma to Absence of oxygen (in yeast) Ethanol + CO2 + Energy lungs. (2-carbon Molecule) (ii) Transport of oxygen: Haemoglobin present in Glucose Pyruvate Lactic acid (6-carbon In cytoplasm (6-carbon Lack of oxygen (in muscle cells) (3-carbon + Energy the blood takes up the oxygen from the air in the Molecule) Molecule) Molecule) + energy lungs. It transports the oxygen to tissues which In presence of oxygen (in mitochondria) CO2 + Water + Energy are deficient in oxygen before releasing it. 12. How are water and minerals transported in 15. How are the lungs designed in human plants? beings to maximise the area for exchange of Ans. The roots of a plant consists of hairs called root gases? hair. Ans. Within the lungs, the air passage differentiates In plants, water and minerals are transported into smaller tubes, known as bronchi which in through xylem cells from soil to the leaves. turn form bronchioles. The bronchioles terminates The xylem cells of roots, stems and leaves are in balloon-like structures, known as alveoli. The interconnected to form a conducting channel that alveoli present in the lungs give maximum surface reaches all parts of the plant body. The root cells area for exchange of gases. The alveoli are thin take ions from the soil. This creates a difference walled. They form an extensive network of blood between the concentration of ions present in roots vessels to allow exchange of gases. and soil. Therefore, there is a steady movement of 16. What are the components of the transport water into the xylem. An osmotic pressure builds system in human beings? What are the up, there is a movement of water and minerals functions of these components ? from one cell to the other cell due to osmosis. The continuous loss of water takes place due Ans. The transport system (circulatory system) in to transpiration. Transpiration creates a suction human beings mainly comprises of heart, blood pressure as a result of which water is forced into and blood vessels. the xylem cells of roots. The effect of root pressure (i) Function of blood vessels: The blood pumped for transportation in plants is more important at by the heart flows through the blood vessels night while during daytime transpiration pull (arteries, veins and capillaries) and also comes becomes the major driving force. back to the heart through them. Life Processes 3  (ii) Function of heart: The heart receives in animals that have high energy requirement. deoxygenated blood from the body parts and Mammals and birds constantly require oxygen transport it to lungs to enrich it with oxygen. It to obtain energy to maintain their constant body receives purified blood from lungs and pumps it temperature. to all the body parts. 18. What are the components of the transport (iii) Function of blood: Blood transports oxygen, system in highly organised plants? digested food, carbon dioxide, hormones and Ans. In highly organised plants there are two conducting nitrogenous waste such as urea. It also protects tissues namely xylem and phloem. the body from diseases and regulates the body temperature. Xylem consists of vessels, tracheids and other xylem tissues. The interconnected vessels and 17. Why is it necessary to separate oxygenated and tracheids form a continuous system of water deoxygenated blood in mammals and birds? conducting channels reaching all region of the Ans. Separation of oxygenated and deoxygenated plant. Xylem carries water and minerals. blood allows enough supply of oxygen to the Phloem transport soluble products of body as it avoids mixing of the oxygenated photosynthesis from leaves to different area of and deoxygenated blood. This system is useful the plant body. 4 UDAAN Study Material Class-X PW  NCERT Exercise 1. The kidneys in human beings are a part of the 6. What is the role of saliva in the digestion of food? system for: Ans. Saliva has salivary amylase enzyme that converts (a) Nutrition (b) Respiration starch into sugars like maltose. (c) Excretion (d) Transportation Starch Maltose + Salivary amylase (Complex Molecule) (Simpler Molecule) Ans. (c) Saliva maintain also moistens the food that help 2. The xylem in plants are responsible for: in chewing and breaking down the larger pieces of (a) Transport of water food into smaller ones. (b) Transport of food 7. What are the necessary conditions for autotrophic (c) Transport of amino acids nutrition and what are its by-products? (d) Transport of oxygen Ans. The most essential conditions for autotrophic Ans. (a) nutrition are: 3. The autotrophic mode of nutrition requires: (i) Sufficient sunlight. (a) Carbon dioxide and water (ii) Sufficient supply of carbon dioxide. (b) Chlorophyll (iii) Presence of chlorophyll. (c) Sunlight (iv) Sufficient transport of water to green plants or cells (d) All of the above of the plant. Ans. (d) Carbohydrates and oxygen are the by-products of autotrophic nutrition. 4. The breakdown of pyruvate to give carbon dioxide, water and energy occurs in ________. 8. What are the differences between aerobic and (a) Cytoplasm (b) Mitochondria anaerobic respiration? Name some organisms (c) Chloroplast (d) Nucleus that use the anaerobic mode of respiration. Ans. (b) Ans. The differences between anaerobic and aerobic respiration are as follows: 5. How are fats digested in our bodies ? Where does this process take place ? Anaerobic respiration Aerobic respiration Ans. Digestion of fats occurs mainly in the small intestine. It occurs in the absence It occurs in the presence of oxygen. of oxygen. Bile juice produced by the liver enteres in the small intestine along with pancreatic juice. The bile salts Partial breakdown of Complete breakdown of present in the bile juice emulsify the large globules food takes place. food take place. of fats into smaller globules to provide larger surface Much less energy is More energy is generated area to act upon by the enzymes. produced in anaerobic (38 ATP) respiration. (2 ATP) Pancreatic juice has lipase enzyme breaks down The end products of The end products of emulsified fats in also. Intestinal juice which consists of lipase enzyme that catalyzes the conversion of anaerobic respiration aerobic respiration are fats into fatty acids and glycerol. are carbon dioxide and carbon dioxide and pancreatic juice ethanol (as in yeast) or water. emulsified Fats Emulsified Break lactic acid (as in animal by bile salts lipase fats muscles cells). intestinal Some organisms which use anaerobic mode of down of fats Fatty Acid + Glycerol juice lipase respiration are yeast, bacteria etc. Life Processes 5  9. How are the alveoli designed to maximise the Double circulation is very important in our body exchange of gases ? as: The right side and the left side of the human Ans. heart are essential to separate deoxygenated and (i) Alveoli have balloon-like structure. Thus, provides oxygenated blood and prevents mixing. This type of maximum surface area for exchange of gases. separation of oxygenated and deoxygenated blood ensures an efficient supply of oxygen to the body. (ii) The alveoli are thin walled and have network of This is useful for humans as they constantly require blood vessels to allow exchange of gases between blood and the air filled in alveoli. energy to regulate their body temperature. 10. What would be the consequences of a deficiency 12. What are the differences between the transport of haemoglobin in our bodies? of materials in xylem and phloem ? Ans. The oxygen carrying capacity of blood reduces due Ans. The differences between the transport of materials to the deficiency of haemoglobin in blood. As a in xylem and phloem are given below: result, the production of energy by oxidation will Phloem Xylem become slower. Therefore, an individual can fall Phloem allow the Xylem transports water sick and would feel fatigue and nausea. transport of prepared and dissolved minerals 11. Describe double circulation in human beings. food material from from roots to leaves and Why is it necessary? leaves to other regions other parts of the plants Ans. In our heart, blood is circulated twice. The of plant in dissolved unidirectionally. deoxygenated blood from the body is brought to form bidirectionally the right atrium through vena cava from where 13. Compare the functioning of alveoli in the lungs it is sent to right ventricle. From right ventricle, and nephrons in the kidneys with respect to their the blood is pumped to the lungs for oxygenation structure and functioning. through pulmonary artery. Again, the oxygenated blood from lungs enters the left atrium of the Ans. heart through pulmonary veins. From left atrium, Nephron Alveoli it is carried to the left ventricle, from where this A kidney has around 1 A mature lung has around oxygenated blood is pumped to different parts of million nephrons. 300 million alveoli. body through the arteries. Through this, the blood flows from the heart two times, and thus, it is called Functional unit of Functional unit of ‘double circulation’. kidney. lungs. 6 UDAAN Study Material Class-X PW