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Life Process Class-X

  1. Prepared by:- Shivank Bhardwaj Class:- X-G Roll No. 38 Under Guidance of Bharti Pant Mam
  2.  The most important criteria to decide whether something is alive is movement. All living things move without the help of any external help. Some movements are easily visible like the movements of body parts. Some movements are not easily visible like molecular movements. The molecular movements in cells and tissues is necessary for all life processes.
  3. Life processes are the basic processes in living organisms which are necessary for maintaining their life. The basic life processes are – nutrition, respiration, transportation, and excretion. i) Nutrition :– is the process of taking food by an organism and its utilization by the body for life processes. ii) Respiration :– is the process by which food is burnt in the cells of the body with the help of oxygen to release energy. iii) Transportation :– is the process by which food, oxygen, water, waste products are carried from one part of the body to the other. iv) Excretion :- is the process by which waste products are removed from the body.
  4.  Nutrition is the process of taking food by an organism and its utilisation by the body to build the body, for growth, to repair the damaged parts of the body and for energy.  Life on earth depends on carbon based molecules and most of the food are also carbon based molecules. The outside raw materials used by living organisms are food, water and air. 1) Modes of nutrition :- There are two main modes of nutrition. They are autotrophic nutrition and heterotrophic nutrition. i. Autotrophic nutrition :- is nutrition in which organisms prepare their own food from simple inorganic substances like carbon dioxide and water in the presence of sunlight and chlorophyll. Eg :- all green plants and some bacteria. ii Heterotrophic nutrition :- is nutrition in which organisms get their food directly or indirectly from plants. Eg :- all animals fungi and some bacteria.
  5. 2) Types of heterotrophic nutrition :- There are three main types of heterotrophic nutrition. They are saprophytic, parasitic and holozoic nutritions. 1. Saprohytic nutrition :- is nutrition in which organisms get their food from dead and decaying organisms. They break down the food material outside their body and then absorbs it. Eg :- mushroom, bread mould, yeast, some bacteria etc. 2. Parasitic nutrition :- is nutrition in which organisms get their food from living organisms (host) without killing them. Eg :- cuscuta, orchids, ticks, lice, leeches, round worm, tape worm, plasmodium etc. 3. Holozoic nutrition :- is nutrition in which organisms take food directly and then digests and absorbs it. Eg :- amoeba, paramaecium, birds, fishes, humans etc.
  6. Photosynthesis :- is the process by which plants prepare food by using carbon dioxide and water in the presence of sunlight and chlorophyll. The food prepared is carbohydrate which is stored in the form of starch. Oxygen is released in this process. Equation of photosynthesis :- Sunlight 6CO2 + 12H2O ----------------- C6H12O6 + 6H2O + 6O2 Chlorophyll Process of photosynthesis :- Photosynthesis takes place in three main steps. They are :- i) Absorption of light energy by chlorophyll. ii) Conversion of light energy into chemical energy and splitting up of water molecules into hydrogen and oxygen. iii) Reduction of carbon dioxide by hydrogen to form carbohydrates.
  7. Chlorophyll :- are the green pigments present in the leaves. If we observe a cross section of a leaf under a microscope, we can see cells containing green dot like structures called chloroplasts which contain chlorophyll.
  8.  Show that chlorophyll is necessary For photosynthesis :- 1. Take a potted plant having variegated leaves (croton plant). Keep it in a dark room for three days so that all the starch is used up. Then keep it in sunlight for 6 hours. Then take a leaf from the plant and mark the green areas of the leaf on a sheet of paper. Then dip the leaf in boiling water to make it soft. Then dip the leaf in alcohol and heat it in a water bath to decolourise it and remove the chlorophyll. Then wash the leaf in water and dip it in dilute iodine solution. It will be seen that only the green parts of the leaf turns blue black. This shows that chlorophyll is necessary for photosynthesis.
  9. 1. Take a potted plant having variegated leaves (croton plant). Keep it in a dark room for three days so that all the starch is used up. Then keep it in sunlight for 6 hours. Then take a leaf from the plant and mark the green areas of the leaf on a sheet of paper. Then dip the leaf in boiling water to make it soft. Then dip the leaf in alcohol and heat it in a water bath to decolourise it and remove the chlorophyll. Then wash the leaf in water and dip it in dilute iodine solution. It will be seen that only the green parts of the leaf turns blue black. This shows that chlorophyll is necessary for photosynthesis. To show that chlorophyll is necessary for photosynthesis :-
  10. I. Nutrition in amoeba :- 1. Amoeba is a unicellular animal living in water. It takes in food by forming finger like projections called pseudopodia and forms a food vacuole. Inside the food vacuole the food is digested and absorbed. The undigested food is then sent out through the surface of the cell.
  11. 1. Nutrition in human beings takes place in the digestive system. It consists of the alimentary canal and glands which produce enzymes which breaks down food into smaller molecules. 2. The main organs of the digestive system are mouth, oesophagus, stomach, small intestine, large intestine, and anus. The main glands are salivary glands, gastric glands, liver, pancreas and intestinal glands.
  12.  In the mouth :- the food is broken down into smaller particles by the teeth and mixed with saliva from the salivary glands. Saliva contains the enzyme salivary amylase which converts starch into sugar. Then the food passes through the oesophagus into the stomach.  In the stomach :- the gastric glands produce gastric juice which contains the enzyme pepsin, hydrochloric acid and mucous. Pepsin breaks down proteins. Hydrochloric acid makes the medium acidic and helps in the action of pepsin. Mucous protects the walls of the stomach from the action of the acid. Then the food passes into the small intestine.  In the upper part of the small intestine called duodenum :- the food is mixed with bile from liver and pancreatic juice from the pancreas. Bile breaks down fats into smaller globules. Pancreatic juice contains the enzymes trypsin and lipase. Trypsin breaks down proteins and lipase breaks down fats.  In the small intestine :- the glands the walls of the small intestine produces intestinal juice. The enzymes of the intestinal juice coverts carbohydrates into glucose, fats into fatty acids and glycerol and proteins into amino acids. The walls of the small intestine has several finger like projections called villi having blood vessels. It helps to increase the surface area for the absorption of digested food. The digested food is absorbed by the blood and transported to all cells in the body. Then the undigested food passes into the large intestine.  In the large intestine :- water is absorbed and the waste material is removed through the anus.
  13. 1. Respiration is the process by which food is burnt in the cells of the body with the help of oxygen to release energy. It takes place in the mitochondria of the cells. 2. The energy released during respiration is used to make ATP molecules (Adenosine tri phosphate) from ADP molecules (Adenosine di phosphate) and inorganic phosphate. Energy ADP + Phosphate  ATP Respiration 3. Energy is stored in the cells in the form of ATP molecules. When the cells need energy, ATP is broken down in the presence of water to form ADP and energy is released. Water ATP  ADP + Energy
  14. b) Types of respiration :- There are two main types of respiration. They are aerobic and anaerobic respiration. I Aerobic respiration :- takes place in the presence of oxygen. It produces more energy. The end products are carbon dioxide, water and energy. It takes place in most organisms. II In aerobic respiration glucose is converted into pyruvate in the cytoplasm in the presence of oxygen and then in the presence of oxygen, pyruvate is converted into carbon dioxide, water and energy in the mitochondria. presence of oxygen presence of oxygen Glucose  Pyruvate  CO2 + H2O + Energy cytoplasm mitochondria
  15. ii) Anaerobic respiration :- takes place in the absence of oxygen. It produces less energy. The end products are lactic acid or ethanol, carbon dioxide, and energy. It takes place in muscle cells and yeast. In anaerobic respiration in muscle cells, glucose is converted into pyruvate and in the absence of oxygen pyruvate is converted into lactic acid and energy. presence of oxygen absence of oxygen Glucose Pyruvat Lactic acid + Energy cytoplasm muscle cells In anaerobic respiration in yeast, glucose is converted into pyruvate and in the absence of oxygen pyruvate is converted into ethanol, carbondioxide and energy. This process is called fermentation. presence of oxygen absence of oxygen Glucose Pyruvate Ethanol + CO2 + Energy cytoplasm yeast
  16.  The main organs of the respiratory system are nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, lungs and diaphragm.
  17. 1. Air enter through the nostrils. The hairs and mucous traps the dust particles. It then passes through the phraynx, larynx, trachea, bronchi and enters the lungs. The trachea has rings of cartilage which prevents it from collapsing when there is no air in the trachea. The bronchi divides into smaller tubes called bronchioles which ends in tiny air sacs called alveoli. The alveoli is supplied with blood vessels through which exchange of gases takes place. The alveoli helps to increase the surface area for the exchange of gases.
  18.  Mecahanism of breathing :- 1. When we breathe in air, the muscles of the diaphragm contracts and moves downward and the chest cavity expands and air enters into the lungs. 2. When we breathe out air, the muscles of the diaphragm relaxes and moves upward and the chest cavity contracts and air goes out of the lungs.
  19. 8) Transportation :- a) Transportation in Humanbeings :- The main transport system in human beings is the circulatory system. It consists of blood, arteries, veins capillaries and heart. i) Blood :- transports food, oxygen and waste products. It consists of plasma, red blood cells (RBC), white blood cells (WBC) and platelets. Plasma transports food, water, carbondioxide, nitrogenous waste etc. Red blood cells transports oxygen. White blood cells kills harmful microbes and protects the body. Platelets help in clotting of blood and prevents loss of blood during injury. ii) Arteries :- carry pure blood from the heart to all parts of the body. They are thick walled and do not have valves. iii) Veins :- carry impure blood from all parts of the body to the heart. They are thin walled and have valves. iv) Capillaries :- are very narrow blood vessels which connects arteries and veins together. The exchange of food, water, oxygen, carbon dioxide etc. between the blood and cells take place through the capillaries.
  20. Heart :- is a muscular organ which pumps blood to all parts of the body. It has four chambers. The upper chambers are called atria and the lower chambers are called ventricles. Since the ventricles pump blood to the different organs its walls are thicker than the atria. The right and left chambers are separated by a septum. It prevents the mixing of oxygenated and deoxygenated blood The atria and ventricles have valves between them to prevent blood flowing backward.
  21. Working of the heart ( Circulation of blood ) :- When the left atrium relaxes oxygenated blood from the lungs flows into it through the pulmonary vein. When it contracts, the left ventricle expands and the blood flows into it. Then the left ventricle contracts and the oxygenated blood is pumped out through the aorta to all parts of the body. After circulating through all parts of the body the deoxygenated blood enters the right atrium through the vena cava. When the right atrium contracts, the right ventricle expands and the blood flows into it. Then the right ventricle contracts and the blood is pumped to the lungs through the pulmonary artery. In the lungs carbon dioxide is removed and oxygen is absorbed and the oxygenated blood again enters the left atrium and the process repeats. Since blood flows through the heart twice in one cycle, it is called double circulation. Lymph :- is a colourless fluid present in intercellular spaces. It is formed from the plasma which escapes from the capillaries. Lymph drains into lymphatic capillaries which forms lymph vessels and joins into large veins. Lymph transports digested fats and drains excess fluids from intercellular spaces back into the blood. It contains lymphocytes which kills germs and protects the body
  22. i) The heart in mammals :- and birds have four chambers and the right and left sides of the heart is separated by a septum. This prevents mixing of oxygenated and deoxygenated blood and provides efficient supply of oxygen. This is necessary because they need more energy to maintain their body temperature. ii) The heart in amphibians and reptiles :- have three chambers and allows some mixing of oxygenated and deoxygenated blood because the do not use energy to maintain their body temperature. Their body temperature is the same as the temperature of the surroundings. iii) The heart in fishes :- have only two chambers and blood is oxygenated in the gills.
  23. In plants, transportation of materials like food, water and minerals takes place through conducting tissues called xylem and phloem. i) Xylem :- transports water and minerals from the roots to all parts of the plant. It consists of xylem vessels and tracheids. Water and minerals enter the roots by diffusion. Then due to transpiration, the suction force helps in the upward movement of water an minerals.
  24. ii) Phloem :- transports food from the leaves to the other parts of the plant. This process is called translocation. The phloem consists of sieve tubes and companion cells. Food from the leaves is transferred to the xylem by the energy of ATP molecules. Due to osmotic pressure water enters the phloem and helps in the transport of food.
  25. 1. Excretion is the process by which the waste products produced during metabolic activities is removed from the body. 2. In unicellular organism the waste products are removed from the cells into the surroundings by diffusion. 3. In multicellular organisms the waste prducts are removed through specialised organs.
  26. Excretion in Human beings :- I The excretory system consists of a pair of kidneys , a pair of ureters, urinary bladder and urethra. Each kidney has a number of excretory units called nephrons.
  27. Nephron :- Each nephron has a cup like structure called Bowman’s capsule containing a bundle of capillaries called glomerulus. The Bowman’s capsule leads into a tubular structure which joins into a collecting duct. The renal artery brings the nitrogenous waste like ammonia, urea, uric acid (urine) along with excess water, salts etc. into the nephron. It filters the nitrogenous waste, water and salts which passes through the tubular structure into the collecting duct. The waste then passes through the ureters into the urinary bladder and is then sent out through the urethra as urine.  The useful products like amino acids, glucose, salts etc. are reabsorbed by the capillaries around the tubular structure and goes into the real vein. b) Excretion in plants :- In plants the gaseous waste products produced during respiration (CO2) and photosynthesis (O2) are removed through the stomata. Excess water is removed through the stomata. This process is called transpiration. Some waste products are stored in the leaves and removed when the leaves dry and fall off. Some waste products are stored in vacuoles. Some waste products like gums and resins are stored in the old xylem cells. Some waste products are removed through the roots.
  28. MCQ - QUESTIONS Q-1 A gland not associated with alimentary canal is :- A Liver C Pancreas B Salivary Gland D Adrenal Q-2 A bio-chemical compound that readily combines with oxygen and distributes it throughout stomata is called :- A Water C HB B Urea D Acetylcholine
  29. Q-3 The process in which loss of water takes place in the form of water vapours through stomata is called :- A Transportation C Guttation B Transpiration D Translocation Q-4 B.P. Is measured by instrument called :- A Barometer C Manometer B Sphygmomanometer D photometre Q-5 Filteration units of Kidney are :- A Ureter C Neurons B Urethra D nephrons Q-6 The opening and closing of stomatal pore depends upon :- A oxygen C concentration of CO2 units B temperature D water in guard cells
  30. Q-7 Autotrophic organisms include :- A bacteria and virus B bacteria and fungi C green plants and some bacteria D green plants and all bacteria Q-8 which of the following is chiefly digested in the stomach :- A carbohydrates B Proteins C Lipids D Fats Q-9 in a closed circulatory system blood is enclosed with :- A vessels B heart C skeleton D sinuses
  31. Q-10 large intestine carries out :- A absorption B assimilation C digestion of fats D digestion of carbohydrates Q-11 normal blood pressure :- A 120/80 mm of Hg C 120/60 mm of Hg B 160/80 mm 0f Hg D 180/80 mm of Hg
  32. In the following questions, a statement of Assertion is followed by a statement of Reason. Mark the correct choice as :- (a)If both Assertion and Reason are true, and Reason is the correct explanation of Assertion (b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion (c) If Assertion is true, but Reason is false (d) If Reason is true, but Assertion is false (e) If both Assertion and Reason are false
  33. Q-1 Assertion: Lungs always contain a residual volume of air. Reason: It is so to ensure enough time for the release of CO2 and for the absorption of O2 . Q-2 Assertion: In a healthy adult, the initial filtrate in the kidneys is about 180 L daily, but the actual volume excreted is only a litre a day. Reason: Most of the filtrate is lost from the body in the form of sweat. Q-3 Assertion: Respiration is opposite of Photosynthesis Q-4 Reason: In Photosynthesis food is made from energy and in Respiration food is converted to energy. Q-5 Assertion: The four chambered heart does not mix oxygenated and deoxygenated blood. Reason: Four chambered heart is found in mammals with advanced body functions. Q-6 Assertion: Translocation of food occurs in Plants. Reason: Xylem tissue is responsible for Translocation.
  34. 3 Marks-Questions Q-1 Mention the two main components of the transport system in plants. State one function of each one of these components ? Q-2 State the function of guard cells. What will happen to guard cells and stomatal pore when water flows to guard cells ? Q-3 Give reason – (i) The two ventricles have thicker muscular walls than the two atria in human heart. (ii) The capillaries have walls which are one-celled thick. Q-4 (i) Name two organisms that obtain food through parasitic nutritive strategy, (ii) How do fungi obtain their food ? Q-5 Give reasons for the following : (i) Glottis is covered by epiglottis (ii) Lung alveoli are covered with blood capillaries (iii) The wall of trachea is supported by cartilage rings.
  35. 5-Marks-Questions Q-1 In single celled organisms, diffusion is sufficient to meet all their requirements of food, exchange of gases or removal of wastes but it is not in case of multicellular organisms. Explain the reason for this difference. Q-2 Name three life processes which are essential for maintaining life and briefly explain the functioning of any one of them. Q-3 Explain the process by which the energy requirements of the autotrophic organisms are fulfilled. In which form the unused carbohydrates get stored ? Q-4 (a) List three events that occur during the process of photosynthesis. State in brief the role of stomata in this process. (b) Describe an experiment to show that sunlight is essential for photosynthesis. Q-5 How do the guard cells regulate opening and closing of stomatal pores ? Explain with the help of diagram. Also indicate what happens to the rate of photosynthesis if stomata get blocked due to dust
  37. ANS-1 Single celled organisms are in direct contact with the environment so that diffusion is helpful to them in exchange of gases, removal of wastes and even meeting their requirement of food. However, in most * multicellular organisms, the body is covered by dead cells. Cell to cell diffusion is unable to meet the requirement of all body cells. For example, in humans cell to cell diffusion will take three .years to send oxygen from lungs to toes. Multicellular organisms have developed specialised structures for performing different functions, e.g., digestive tract, respiratory surface, excretory organs. These structures are connected to all body cells through a transport system, e.g., circulatory system in animals, xylem and phloem in plants. The transport system is quite fast to bring materials to and from the cells 5-MARKERS
  38. ANS-2 Nutrition, respiration, exchange of materials. Nutrition: It is the process by which living beings procure food for obtaining energy and body building materials. Body building materials are usually carbon- based. The food sources are also carbon based. They are, of course, varied. Plants manufacture their own food in the process of photosynthesis. Animals obtain food from outside. Food obtained from outside is first broken down through digestion into simpler soluble substances for absorption. Inside the cells, the simple substances are converted into various complex biochemicals to form components of protoplasm. Some biochemicals function as respiratory substfates
  39. ANS 3 Photosynthesis. It occurs in the following steps : 1.Photolysis: With the help of light energy, oxygen evolving Z-complex splits up water into its components — protons (H+), electrons (e–) and oxygen. 2.Absorption of Light Energy: Chlorophyll absorbs light energy. 3.Primary Reaction: Chlorophyll converts the absorbed light energy into chemical energy. It is called primary reaction of photosynthesis. It builds up ATP with the help of excited electrons. 4.Formation of Reducing Power: Coenzyme NADP+ is changed to reduced form of NADPH. 5.Reduction of CO2: Carbon dioxide is reduced enzymatically with the help of ATP to form carbohydrates. Storage: Starch.
  40. Three Events of Photosynthesis: Information is transmitted from one plant cell to another through plasmodesmata and hormones. Role of Stomata in Photosynthesis. Inward diffusion of carbon dioxide and outword diffusion of oxygen. (b) Sunlight is Essential for Photosynthesis: It is the source of energy for photosynthesis. Light is visible part of the electromagnetic radiations. It has a wavelength of 390-760 nm. Photosynthetically active radiations or PAR are 400-700 nm. Natural source of light is sun but artificial light can also provide energy to plants for their photosynthesis. Plants absorb light mostly in violet- blue and red parts of visible light. Violet-blue light carries more energy as compared to red light. Plants growing under shade of others receive mostly green and some violet light. They have lower rates of photosynthesis. Light has two functions, photolysis of water and excitation of chlorophyll to emit electrons. Photolysis of water produces oxygen, protons and electrons. Electrons and protons (Hydrogen ions) help in producing ATP and NADPH2, popularly called assimilatory power. Answer-4
  41. Re Ans-5 Regulation of Stomatal Pore: Opening and closing of stomata is regulated by gain or loss of turgidity of their guard cells. During opening of stomata, guard cells withdraw K+ ions from surrounding epidermal cells, followed by absorption of water from them. As a result, guard cells swell up and become turgid. Their outer thin and elastic walls bend outwardly followed by outward movement of thicker inner walls. The latter creates a pore in between the two guard cells. During closure movement of stomata, guard cells send out K+ ions. Water also passes out. Guard cells become flaccid. Their inner thick walls come to touch each other. The stomatal pore gets closed. Blocking of Stomata: 1.Photosynthesis will be reduced, 2.There will be no gaseous exchange and transpiration. As a result leaves will burn up in hot summer sun.
  42. 3-MARKERS ANS 1 Transport system of plants consists of two main components, xylem and phloem. Xylem (through vessels and tracheids) takes part in conduction of sap mostly in the upward direction. Phloem (through sieve tubes) transports food marterials both in upward and downward directions ANS 2 Function of Guard cells : Opening, closing and regulating the stomata or stomatal pores. Flow of Water : Passage of water into guard cells will make them turgid. The turgid guard cells bend is such a way as to open the stomatal pore
  43. ANS-3 (i) Atria are to receive blood from veins and pump the same into adjacent ventricles only. They have, therefore, thin walls. Ventricles are to pump blood into arteries forcefully as it is to be sent to lungs (right ventricle) and all parts of the body (left ventricle). Therefore, walls of ventricles are thick and muscular with those of left ventricle being thicker. (ii) Capillaries take part in exchange of materials (nutrients, wastes, gases) between blood and tissue fluid. Ans - 4 (i) Parasitic Nutrition. Cuscuta (a plant), Plasmodium (Malarial Parasite) (ii).Most of the fungi are saprotrophs. They obtain their nourishment from organic matter.
  44. Ans-5 (i) Epiglottis. To prevent entry of food and water during swallowing. (ii) Lung Alveoli. Lung alveoli constitute the respiratory surface of the lungs. Their walls have rich supply of blood for gaseous exchange, i.e. passage of oxygen from alveolar air to blood and passage of carbon dioxide from blood to alveolar air. (iii) Tracheal Rings (C-shaped). For providing support, preventing collapse of trachea and allowing for uninterrupted flow of air.