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Q1) Draw a neat diagram of excretory system of human beings and label the following:                                                                         (i) Kidney                                (ii) Ureter                                               (iii) Urinary Bladder                              (iv) Urethra    

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Q1) Draw a neat diagram of excretory system of human beings and label the following:                                                                         (i) Kidney                                (ii) Ureter                                               (iii) Urinary Bladder                              (iv) Urethra    

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2. Describe double fertilization in plants.                                                                                                      Solution: case of plants, the pollen grain releases two male gametes. One fuses with the egg and forms the zygote. The other male gamete fuses with the two polar nuclei. This fusion is said to be triple fusion. Thus, inside an embryo sac, two fusions, syngamy and triple fusion, take place.                                          This mechanism of two fusions occurring in an embryo sac is called double fertilization.              

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2. Describe double fertilization in plants.                                                                                                      Solution: case of plants, the pollen grain releases two male gametes. One fuses with the egg and forms the zygote. The other male gamete fuses with the two polar nuclei. This fusion is said to be triple fusion. Thus, inside an embryo sac, two fusions, syngamy and triple fusion, take place.                                          This mechanism of two fusions occurring in an embryo sac is called double fertilization.              

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Q3) Draw a diagram of human respiratory system and label the following: (i) part where air is filtered by fine hair and mucus. (ii) part which terminates in balloon – like structures.(iii) balloon – like structures where exchange of gases takes place. (iv) part  which separates chest cavity from abdominal cavity. (b) Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms? Answer:- (a)Quantity of dissolved oxygen is fairly low in water as compared to the amount of oxygen in air. Aquatic organisms therefore have to  breath faster than terrestrial organisms to absorb the required amount of oxygen from the water.                                                                                                                                                                                                                                                                                                                                                                                                                                                         

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Q3) Draw a diagram of human respiratory system and label the following: (i) part where air is filtered by fine hair and mucus. (ii) part which terminates in balloon – like structures.(iii) balloon – like structures where exchange of gases takes place. (iv) part  which separates chest cavity from abdominal cavity. (b) Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms? Answer:- (a)Quantity of dissolved oxygen is fairly low in water as compared to the amount of oxygen in air. Aquatic organisms therefore have to  breath faster than terrestrial organisms to absorb the required amount of oxygen from the water.                                                                                                                                                                                                                                                                                                                                                                                                                                                         

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Q3) State two differences between arteries and veins.                       Answer:- Arteries: Arteries carry oxygenated blood, away from the heart except pulmonary artery. These are thick-walled, highly muscular except arteries of cranium and vertebral column. Valves are absent.Blood in arteries moves with pressure. Veins: Veins carry deoxygenated blood, towards the heart except pulmonary veins. These are thin-walled. Valves are present which provide unidirectional flow of blood. Blood in veins moves under very low pressure.                                    

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Q3) State two differences between arteries and veins.                       Answer:- Arteries: Arteries carry oxygenated blood, away from the heart except pulmonary artery. These are thick-walled, highly muscular except arteries of cranium and vertebral column. Valves are absent.Blood in arteries moves with pressure. Veins: Veins carry deoxygenated blood, towards the heart except pulmonary veins. These are thin-walled. Valves are present which provide unidirectional flow of blood. Blood in veins moves under very low pressure.                                    

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4. How are the alveoli designed to maximise the exchange of gases?                    Answer.                                             Alveoli are small pouches or sacs like structure. They are surrounded by blood capillaries. Thus a large amount of air is brought in contact with the air in the lungs. More than millions of alveoli are present in the lungs. The presence of millions of alveoli in the lungs provides a very large surface area for the exchange of gases. The availability of large surface area maximises the exchange of gases.                                      32. Name two excretory products other than 02 and CO2 in plants.                                  Answer.                                                                           The two excretory products other than 02 and CO2 in plants are resins and gums.

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(c) How opening and closing of stomata takes place?                                       Answer. (a) The breathing cycle involves inhalation and exhalation of air due to alternate expansion and contraction of thoracic cavity. Thus it is a rhythmic process. But exchange of gases is a continuous process as it takes place between the blood and each and every cell, by diffusion.             (b) The circulatory system will become inefficient if it develops a leak. This could be avoided by maintaining a normal blood pressure.               (c) When water flows into the guard cells, the guard cells swell and the stomatal pore opens up. When water moves out the guard cells shrinks and the stomatal pore closes.                               

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(c) How opening and closing of stomata takes place?                                       Answer. (a) The breathing cycle involves inhalation and exhalation of air due to alternate expansion and contraction of thoracic cavity. Thus it is a rhythmic process. But exchange of gases is a continuous process as it takes place between the blood and each and every cell, by diffusion.             (b) The circulatory system will become inefficient if it develops a leak. This could be avoided by maintaining a normal blood pressure.               (c) When water flows into the guard cells, the guard cells swell and the stomatal pore opens up. When water moves out the guard cells shrinks and the stomatal pore closes.                               

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Q3) (a)“The breathing cycle is rhythmic whereas exchange of gases is a continuous process”. Justify this statement. (b) What happens if conducting tubes of circulatory system develops a leak? State in brief, how could this be avoided?                                                               

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Q3) (a)“The breathing cycle is rhythmic whereas exchange of gases is a continuous process”. Justify this statement. (b) What happens if conducting tubes of circulatory system develops a leak? State in brief, how could this be avoided?                                                               

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Draw a diagram of the front view of human heart and label any six parts including at least two, that are concerned with arterial blood supply to the heart muscles        

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Draw a diagram of the front view of human heart and label any six parts including at least two, that are concerned with arterial blood supply to the heart muscles        

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(a) Draw a diagram depicting Human Alimentary Canal and label on it: Gall bladder, Liver and Pancreas.        (b) State the roles of Liver and Pancreas.                  (c) Name the organ which performs the following functions in humans:       (i) Absorption of digested food                                   (ii) Absorption of water.                                       

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(a) Draw a diagram depicting Human Alimentary Canal and label on it: Gall bladder, Liver and Pancreas.        (b) State the roles of Liver and Pancreas.                  (c) Name the organ which performs the following functions in humans:       (i) Absorption of digested food                                   (ii) Absorption of water.                                       

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(i) Write the balanced chemical equation for the process of photosynthesis.

(ii) When do the desert plants take up carbon dioxide and perform photosynthesis ?

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Write whether the following statements are true or false.                                                                                
 1. Fertilization is the fusion of the sperm and the ovum.                           2. Duration of menstrual cycle in human female is 20 days.                              3. Onset of menstruation is termed menopause.     4. In human beings, male attains puberty little later than females.                                                     

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Write whether the following statements are true or false.                                                                                
 1. Fertilization is the fusion of the sperm and the ovum.                           2. Duration of menstrual cycle in human female is 20 days.                              3. Onset of menstruation is termed menopause.     4. In human beings, male attains puberty little later than females.                                                     

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Q4) what is binary and multiple fission ?         

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Q4) what is binary and multiple fission ?         

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Find the missing  step in budding of yeast.

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Find the missing  step in budding of yeast.

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Budding is a form of asexual reproduction usually observed in yeast.
• During this process, a small protrusion appears on the upper portion of the body of the organism. This bulge is called a bud.
•
• From this newly budded cell, another bud appears at the tip.
• This process continues and a chain of yeast cells is obtained.

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Q5) What are enzymes? Name any one enzyme of our digestive system and write its function. Answer:- Enzymes are biological catalysts. Catalysts are proteins that increase the rate of chemical reactions without being used up. For example: Amylase catalyses the breakdown of starch into sugars in the mouth and small intestine. Q6) (i)Write the balanced
 chemical equation for the process of photosynthesis,(ii) When do the  desert plants take up carbon dioxide and perform photosynthesis? Answer:- (i) Photosynthesis can be represented using a chemical  equation. The overall balanced equation is : (ii) Desert plants open up their stomata during night and take in CO2. Stomata remains close during the day time to prevent the loss of water by transpiration. They store the CO2  ? in their cells until the sun comes out and they can carry on with photosynthesis during the day time. Short Answer Type Questions[ll] [3 Marks] -Year 20153. Q3) 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. Answer:-  Unicellular organisms can absorb sufficient  oxygen because of its complete contact with the atmosphere, but in  multicellular organisms the rate of absorption and diffusion becomes very    less because all cells are not in direct contact with the atmosphere. Multicellular organisms require greater amount of oxygen to sustain life processes which cannot be fulfilled by the process of diffusion. Q4) Draw a   diagram of human excretory system and label kidneys, ureters on it.            Q5) Name the acid presents in the following: (i)Tomato (ii)Vinegar (iii)Tamarind.  Answer:- (i) Oxalic acid (ii) citric acid (iii) Tartaric acid.             Q6) State the role of the following in human digestive system: (i) Digestive enzymes (ii) Hydrochloric acid (iii) Villi  Answer:- (i) Digestive enzymes –      Foods need to be broken into their small or simplermolecules so that they can be absorbed into the bloodstream. However, the physical breakdown m of food is not enough. Enzymes are hence needed for the chemical breakdown of food and speeding up the digestive process. The products of  digestion can hence be small enough to be absorbed. (ii) Hydrochloric acid– Hydro chloric acid helps to kill the germs which might have entered in to the system through food. It creates acidic medium for the pepsin to act on food to breakdown proteins. (iii) Villi – Villi are finger like projections in the small intestine. They help to increase the surface area. for absorption of the digested food. Villi are richly supplied with blood  vessel which help to absorb digested food in to the blood stream.Long Answer Type Question [5 Marks] -Year 2015 Q5) (a)Explain how does the  exchange of gases occur in plants across the surface of stems, roots and  leaves. (b) How are water and minerals transported in plants ? Answer:-=(a) In plants there are tiny pores called stomata on leaves and lenticels in  stem which facilitate the exchange of gases. Carbon dioxide is taken in and oxygen given out {during photosynthesis} and vice versa during respiration. (b) Water and minerals are transported within the plant by the Xylem vessels (mainly in an upward direction); these are part of the vascular system which also includes Phloem vessels.Phloem transports the products of photosynthesis within the plant, to all parts like the stem, roots, fruits etc. in all directions.Very Short Answer Type Question [1 Mark] Q8) Mention the raw materials required for photosynthesis. Answer:- The following raw materials are required for photosynthesis: (i) Carbon Dioxide: Plants get CO2 from atmosphere through stomata. (ii)Water: Plants absorb water from soil through roots and transport to leaves. (iii) Sunlight: Sunlight, which is absorbed by the chlorophyll and other green parts of the plant. Short Answer Type Questions[l] [2 Marks] -Year  Q9) Why do herbivores have longer, small intestine than carnivores? Answer:- Digestion of cellulose takes a longer time. Hence, herbivores eating grass  need a longer small intestine to allow complete digestion of cellulose. Carnivorous animals cannot digest cellulose due to the absence of enzyme   CELLULASE, hence they have a shorter intestine. Q9)Write correct sequence of four steps of method for the preparation of temporary mount of a stained leaf peel.Answer.Take a healthy leaf from the potted plant.Remove a part of the peel from the lower surface of the leaf. You can do this by folding the leaf over and gently pulling the peel apart using forceps. Keeps the peel in a watch glass containing water. Put a few drops of safranin stain in a watch glass.After 2-3 minutes take out the peel and place it on a clean glass slide.Put a drop of glycerin over the peel and place a clean covers lip gently over it with the help of a needle. Remove the excess stain and glycerin with the help of blotting paper. Observe the slide under magnifications of the compound microscope. Q10) In. mammals and birds why is it necessary to separate oxygenated and de- oxygenated blood ? Answer:- Mammals and birds are warm blooded animals. This means they can control their body temperature and do not have to depend on environment for their body temperature regulation. Because of this birds and mammals require optimum oxidization of glucose which would be possible with good supply of oxygen. So it is required to have separate oxygenated and de-oxygenated blood to supply the required amount of oxygen. Q11) Draw a neat diagram of excretory system of human beings and label on it: (i)Left kidney (ii)Urinary bladder     Q12) Draw a diagram of human respiratory system and label on it : (i) Diaphragm (ii) Larynx                          Answer(a) Name the site of exchange of material between the blood and surrounding cells. (b) Draw a schematic representation of transport and exchange of oxygen and carbon dioxide in human body. Answer. (a) Capillaries(b) What would be the consequences of deficiency of hemoglobin in your body?Answer.The deficiency of hemoglobin in our body is called anemia. In anemia, the blood is unable to carry the sufficient amount of oxygen required by the body. So, respiration would be less and less energy will be available to the body. The hemoglobin deficient person will feel weak, pale, lethargic and will beunable to perform heavy physical work.Short Answer Type Questions[ll] [3 Marks] -Year 201316.                          List three characteristics of lungs which make it an efficient respiratory surface.                          Answer. These features which particularly make our lungs efficient for gas exchange. 1.Thin: the air sac walls are very thin so that gases can quickly diffuse through them. Oxygen is absorbed in to the blood and carbon dioxide is given out in to the lungs to be exhaled out. 2.Moist: the air sacs are moist with mucus so that gases can dissolve before diffusing.                         3.Large surface area: the surface area for gases to diffuse through in human lungs is roughly the same as a tennis court. The alveoli help to increase the surface area for absorption of oxygen.                            4.Good blood supply: the air sacs or the alveoli have a large capillary network so that large volumes of gases can be exchanged. More the flow of blood more exchange. 17.(a) What is the role of HCl in our stomach ?(b) What is emulsification of fats ?(c) Which protein digesting enzyme is present in pancreatic juice ?          Answer.(a)(i) It sterilises food by killing pathogens and other microbes.(ii) It has a pH of 2, which is perfect for entyaus such as pepsin to break down proteins as effectively as possible.(iii) Helps emulsify food (digestion of protein and stimulates the pancreas to produce digestive enzymes and bile) and protects against harmful ‘ bacteria(b) Breakdown of large gloubule fats into smaller fats droplets is known as emulsification.(c) Trypsin is the enzyme secreted by the pancreas which aids in digestion of proteins.                                  18. List in tabular form three differences between arteries and veins. Answer. Answer Type Questions [5 Marks] -.             Q Draw a diagram of human excretory system and label renal artery and urethra.State in brief the function of :renal artery kidney ureter urinary bladder                         Answer.1 Renal artery: The renal artery carries blood to the kidneys from the abdominal aorta. This blood comes directly from the heart and is sent to the-kidneys to be filtered before it passes through the rest of the body. Up to one-third of the total cardiac output per heartbeat is sent to the renal arteries to be filtered by the kidneys. Each kidney has one renal artery that supplies it with blood. The filtered blood then can exit the renal vein.  Kidney: The kidneys perform the essential function of removing waste products from the blood and regulating the water fluid levels. The kidneys regulate the body’s fluid volume, mineral composition and acidity by excreting and reabsorbing water and inorganic electrolytes.                     Ureter: The ureter is a tube that carries urine from the kidney to the urinary bladder.’ There are two ureters, one attached to each kidney. Urinary bladder: The urinary bladder is an expandable muscular sac that stores urine before it is excreted out of the body through the urethra.              20.(a) Draw a diagram of excretory system in human beings and label the following parts. Aorta, kidney, urinary bladder and urethra.(b) How is urine produced and eliminated ?Answer.(a)                               (b) Blood from the heart comes into the kidneys afferent and efferent arteriols from the renal arteries where it enters about 2-3 million nephrons per kidney. Then, it goes through the glomerulus a tugt or bunch of blood capillaries and get rid of some of the unwanted substances like urea, uric acid, creatinine in the blood and then continues through the renal tubules. The loop of Henley, reabsorb certain substances such as water (actually if body is dehydrated, body will send anti-diuretic hormone (ADH) to kidneys to prevent extra water from going into urine and thus saving water for body and get rid of anything else that isn’t wanted, then the urine goes through ureters to bladder and then to urethra where it is excreted out of body as urine.                    Short Answer Question [I] [2 Marks] -                                      Q Why do the walls of the trachea not collapse’when there is less air in it?Answer. Rings of cartilages are present in trachea. These rings support the trachea and do not allow the trachea to collapse when there is less air in it.                                      Short Answer Type Questions [ll] [3 Marks] -                                      Q In human alimentary canal, name the site of complete digestion of various components of food. Explain the process of digestion. Answer.In small intestine, complete digestion of various components of food take place. The process of digestion of food in mouth, stomach and small intestine in humanbody are as follows: Mouth: Digestion of food begins in the mouth. Saliva present in mouth contains a digestive enzyme, called salivary amylase, maltose and dextrins, which breaks down starch into sugar.                           Stomach: Stomach stores and mixes the food received from the oesophagus with gastric juices. The main components of gastric juice are hydrochloric acid, mucus and pepsinogen. Hydrochloric acid dissolves bits of food and creates an acidic medium. In this medium, pepsinogen is converted to pepsin which is a protein-digesting enzyme. Mucus protects the inner lining of the stomach from the action of HC1.Small Intestine: Small intestine is the site of complete digestion of carbohydrates, proteins and fats. Small intestine produces intestinal juice from the glands present in its wall. The intestinal juice helps in further digestion of food. Small intestine also obtains digestive juices from liver and pancreas. The liver produces bile juice that causes emulsification of fats and the pancreas produces pancreatic juice for digesting proteins and emulsified fats. This digested food is finally absorbed through the intestinal walls                       23. List the three kinds of blood vessels of human circulatory system and write ¦ their functions in tabular form. Answer. Three types of blood vessels in human circulatory system are: Arteries, Veins and Capillaries.Their functions are tabulated below: Answer Type Questions [5 Marks] -                                     Q.(a) Draw a diagram to show open stomatal pore and label on it:(i) guard cells(ii) chloroplast(b) State two functions of stomata.(c) How do guard cells regulate the opening and closing of stomatal pore?                                        Answer.(a)                           18(b) Two functions of stomata are:(i) Exchange of gases between the plant and the atmosphere takes place through stomata.(ii)Transpiration in plants takes place through stomata.(c) Opening and Closing of Stomatal Pore: The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them causing the stomatal pore to open. Similarly, the pore closes if the guard cells shrink. As large amount of water is lost through these stomata, the plant closes these pores when it does not require carbon dioxide for photosynthesis.        25.(a).What is saliva?State its role in the digestion of food.          Answer.                                                       Saliva is a watery fluid secreted by the salivary glands in the mouth. The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin.                                                                                                                                                                                                                                              

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Q5) What are enzymes? Name any one enzyme of our digestive system and write its function. Answer:- Enzymes are biological catalysts. Catalysts are proteins that increase the rate of chemical reactions without being used up. For example: Amylase catalyses the breakdown of starch into sugars in the mouth and small intestine. Q6) (i)Write the balanced
 chemical equation for the process of photosynthesis,(ii) When do the  desert plants take up carbon dioxide and perform photosynthesis? Answer:- (i) Photosynthesis can be represented using a chemical  equation. The overall balanced equation is : (ii) Desert plants open up their stomata during night and take in CO2. Stomata remains close during the day time to prevent the loss of water by transpiration. They store the CO2  ? in their cells until the sun comes out and they can carry on with photosynthesis during the day time. Short Answer Type Questions[ll] [3 Marks] -Year 20153. Q3) 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. Answer:-  Unicellular organisms can absorb sufficient  oxygen because of its complete contact with the atmosphere, but in  multicellular organisms the rate of absorption and diffusion becomes very    less because all cells are not in direct contact with the atmosphere. Multicellular organisms require greater amount of oxygen to sustain life processes which cannot be fulfilled by the process of diffusion. Q4) Draw a   diagram of human excretory system and label kidneys, ureters on it.            Q5) Name the acid presents in the following: (i)Tomato (ii)Vinegar (iii)Tamarind.  Answer:- (i) Oxalic acid (ii) citric acid (iii) Tartaric acid.             Q6) State the role of the following in human digestive system: (i) Digestive enzymes (ii) Hydrochloric acid (iii) Villi  Answer:- (i) Digestive enzymes –      Foods need to be broken into their small or simplermolecules so that they can be absorbed into the bloodstream. However, the physical breakdown m of food is not enough. Enzymes are hence needed for the chemical breakdown of food and speeding up the digestive process. The products of  digestion can hence be small enough to be absorbed. (ii) Hydrochloric acid– Hydro chloric acid helps to kill the germs which might have entered in to the system through food. It creates acidic medium for the pepsin to act on food to breakdown proteins. (iii) Villi – Villi are finger like projections in the small intestine. They help to increase the surface area. for absorption of the digested food. Villi are richly supplied with blood  vessel which help to absorb digested food in to the blood stream.Long Answer Type Question [5 Marks] -Year 2015 Q5) (a)Explain how does the  exchange of gases occur in plants across the surface of stems, roots and  leaves. (b) How are water and minerals transported in plants ? Answer:-=(a) In plants there are tiny pores called stomata on leaves and lenticels in  stem which facilitate the exchange of gases. Carbon dioxide is taken in and oxygen given out {during photosynthesis} and vice versa during respiration. (b) Water and minerals are transported within the plant by the Xylem vessels (mainly in an upward direction); these are part of the vascular system which also includes Phloem vessels.Phloem transports the products of photosynthesis within the plant, to all parts like the stem, roots, fruits etc. in all directions.Very Short Answer Type Question [1 Mark] Q8) Mention the raw materials required for photosynthesis. Answer:- The following raw materials are required for photosynthesis: (i) Carbon Dioxide: Plants get CO2 from atmosphere through stomata. (ii)Water: Plants absorb water from soil through roots and transport to leaves. (iii) Sunlight: Sunlight, which is absorbed by the chlorophyll and other green parts of the plant. Short Answer Type Questions[l] [2 Marks] -Year  Q9) Why do herbivores have longer, small intestine than carnivores? Answer:- Digestion of cellulose takes a longer time. Hence, herbivores eating grass  need a longer small intestine to allow complete digestion of cellulose. Carnivorous animals cannot digest cellulose due to the absence of enzyme   CELLULASE, hence they have a shorter intestine. Q9)Write correct sequence of four steps of method for the preparation of temporary mount of a stained leaf peel.Answer.Take a healthy leaf from the potted plant.Remove a part of the peel from the lower surface of the leaf. You can do this by folding the leaf over and gently pulling the peel apart using forceps. Keeps the peel in a watch glass containing water. Put a few drops of safranin stain in a watch glass.After 2-3 minutes take out the peel and place it on a clean glass slide.Put a drop of glycerin over the peel and place a clean covers lip gently over it with the help of a needle. Remove the excess stain and glycerin with the help of blotting paper. Observe the slide under magnifications of the compound microscope. Q10) In. mammals and birds why is it necessary to separate oxygenated and de- oxygenated blood ? Answer:- Mammals and birds are warm blooded animals. This means they can control their body temperature and do not have to depend on environment for their body temperature regulation. Because of this birds and mammals require optimum oxidization of glucose which would be possible with good supply of oxygen. So it is required to have separate oxygenated and de-oxygenated blood to supply the required amount of oxygen. Q11) Draw a neat diagram of excretory system of human beings and label on it: (i)Left kidney (ii)Urinary bladder     Q12) Draw a diagram of human respiratory system and label on it : (i) Diaphragm (ii) Larynx                          Answer(a) Name the site of exchange of material between the blood and surrounding cells. (b) Draw a schematic representation of transport and exchange of oxygen and carbon dioxide in human body. Answer. (a) Capillaries(b) What would be the consequences of deficiency of hemoglobin in your body?Answer.The deficiency of hemoglobin in our body is called anemia. In anemia, the blood is unable to carry the sufficient amount of oxygen required by the body. So, respiration would be less and less energy will be available to the body. The hemoglobin deficient person will feel weak, pale, lethargic and will beunable to perform heavy physical work.Short Answer Type Questions[ll] [3 Marks] -Year 201316.                          List three characteristics of lungs which make it an efficient respiratory surface.                          Answer. These features which particularly make our lungs efficient for gas exchange. 1.Thin: the air sac walls are very thin so that gases can quickly diffuse through them. Oxygen is absorbed in to the blood and carbon dioxide is given out in to the lungs to be exhaled out. 2.Moist: the air sacs are moist with mucus so that gases can dissolve before diffusing.                         3.Large surface area: the surface area for gases to diffuse through in human lungs is roughly the same as a tennis court. The alveoli help to increase the surface area for absorption of oxygen.                            4.Good blood supply: the air sacs or the alveoli have a large capillary network so that large volumes of gases can be exchanged. More the flow of blood more exchange. 17.(a) What is the role of HCl in our stomach ?(b) What is emulsification of fats ?(c) Which protein digesting enzyme is present in pancreatic juice ?          Answer.(a)(i) It sterilises food by killing pathogens and other microbes.(ii) It has a pH of 2, which is perfect for entyaus such as pepsin to break down proteins as effectively as possible.(iii) Helps emulsify food (digestion of protein and stimulates the pancreas to produce digestive enzymes and bile) and protects against harmful ‘ bacteria(b) Breakdown of large gloubule fats into smaller fats droplets is known as emulsification.(c) Trypsin is the enzyme secreted by the pancreas which aids in digestion of proteins.                                  18. List in tabular form three differences between arteries and veins. Answer. Answer Type Questions [5 Marks] -.             Q Draw a diagram of human excretory system and label renal artery and urethra.State in brief the function of :renal artery kidney ureter urinary bladder                         Answer.1 Renal artery: The renal artery carries blood to the kidneys from the abdominal aorta. This blood comes directly from the heart and is sent to the-kidneys to be filtered before it passes through the rest of the body. Up to one-third of the total cardiac output per heartbeat is sent to the renal arteries to be filtered by the kidneys. Each kidney has one renal artery that supplies it with blood. The filtered blood then can exit the renal vein.  Kidney: The kidneys perform the essential function of removing waste products from the blood and regulating the water fluid levels. The kidneys regulate the body’s fluid volume, mineral composition and acidity by excreting and reabsorbing water and inorganic electrolytes.                     Ureter: The ureter is a tube that carries urine from the kidney to the urinary bladder.’ There are two ureters, one attached to each kidney. Urinary bladder: The urinary bladder is an expandable muscular sac that stores urine before it is excreted out of the body through the urethra.              20.(a) Draw a diagram of excretory system in human beings and label the following parts. Aorta, kidney, urinary bladder and urethra.(b) How is urine produced and eliminated ?Answer.(a)                               (b) Blood from the heart comes into the kidneys afferent and efferent arteriols from the renal arteries where it enters about 2-3 million nephrons per kidney. Then, it goes through the glomerulus a tugt or bunch of blood capillaries and get rid of some of the unwanted substances like urea, uric acid, creatinine in the blood and then continues through the renal tubules. The loop of Henley, reabsorb certain substances such as water (actually if body is dehydrated, body will send anti-diuretic hormone (ADH) to kidneys to prevent extra water from going into urine and thus saving water for body and get rid of anything else that isn’t wanted, then the urine goes through ureters to bladder and then to urethra where it is excreted out of body as urine.                    Short Answer Question [I] [2 Marks] -                                      Q Why do the walls of the trachea not collapse’when there is less air in it?Answer. Rings of cartilages are present in trachea. These rings support the trachea and do not allow the trachea to collapse when there is less air in it.                                      Short Answer Type Questions [ll] [3 Marks] -                                      Q In human alimentary canal, name the site of complete digestion of various components of food. Explain the process of digestion. Answer.In small intestine, complete digestion of various components of food take place. The process of digestion of food in mouth, stomach and small intestine in humanbody are as follows: Mouth: Digestion of food begins in the mouth. Saliva present in mouth contains a digestive enzyme, called salivary amylase, maltose and dextrins, which breaks down starch into sugar.                           Stomach: Stomach stores and mixes the food received from the oesophagus with gastric juices. The main components of gastric juice are hydrochloric acid, mucus and pepsinogen. Hydrochloric acid dissolves bits of food and creates an acidic medium. In this medium, pepsinogen is converted to pepsin which is a protein-digesting enzyme. Mucus protects the inner lining of the stomach from the action of HC1.Small Intestine: Small intestine is the site of complete digestion of carbohydrates, proteins and fats. Small intestine produces intestinal juice from the glands present in its wall. The intestinal juice helps in further digestion of food. Small intestine also obtains digestive juices from liver and pancreas. The liver produces bile juice that causes emulsification of fats and the pancreas produces pancreatic juice for digesting proteins and emulsified fats. This digested food is finally absorbed through the intestinal walls                       23. List the three kinds of blood vessels of human circulatory system and write ¦ their functions in tabular form. Answer. Three types of blood vessels in human circulatory system are: Arteries, Veins and Capillaries.Their functions are tabulated below: Answer Type Questions [5 Marks] -                                     Q.(a) Draw a diagram to show open stomatal pore and label on it:(i) guard cells(ii) chloroplast(b) State two functions of stomata.(c) How do guard cells regulate the opening and closing of stomatal pore?                                        Answer.(a)                           18(b) Two functions of stomata are:(i) Exchange of gases between the plant and the atmosphere takes place through stomata.(ii)Transpiration in plants takes place through stomata.(c) Opening and Closing of Stomatal Pore: The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them causing the stomatal pore to open. Similarly, the pore closes if the guard cells shrink. As large amount of water is lost through these stomata, the plant closes these pores when it does not require carbon dioxide for photosynthesis.        25.(a).What is saliva?State its role in the digestion of food.          Answer.                                                       Saliva is a watery fluid secreted by the salivary glands in the mouth. The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin.                                                                                                                                                                                                                                              

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Explain the process of nutrition in Amoeba. Answer.                              Amoeba is an important protozoa found in fresh water. It feeds on microscopic plants and animals present in water. The mode of nutrition in amoeba is Holozoic. And the process of obtaining food by amoeba is called phagocytosis. The different processes involved in the nutrition of amoeba are:         Ingestion                              Ingestion is the process of taking food in the body. Amoeba is a unicellular animal, so it doesn’t have a mouth for ingestion of food. Amoeba ingests the food by encircling it by forming pseudopodia. When the food is completely encircled , the food is engulfed in the form of a bag called food vacuole. Digestion: Digestion is the process of breaking the large and insoluble molecules in small and water soluble molecules. In amoeba, several digestive enzymes react on the food present in the food vacuoles and break it down into simple and soluble molecules. Absorption:                                            The food digested by digestive enzymes is then absorbed in the cytoplasm by the process of diffusion. While the undigested food remains in the food vacuole. If a large amount of food is absorbed by amoeba, the excess food is stored in the cytoplasm ih the form of glycogen and lipids.      Assimilation:                             During this step the food absorbed by the cytoplasm is used to obtain energy, growth and repair. This process of utilizing absorbed food for obtaining energy, repair and growth is called assimilation.        Egestion: When a sufficient amount of undigested food gets collected in the food vacuole, it is thrown out of the body by rupturing cell membrane. The process of removal of undigested food from the body is called egestion.                                                                                                                          

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Explain the process of nutrition in Amoeba. Answer.                              Amoeba is an important protozoa found in fresh water. It feeds on microscopic plants and animals present in water. The mode of nutrition in amoeba is Holozoic. And the process of obtaining food by amoeba is called phagocytosis. The different processes involved in the nutrition of amoeba are:         Ingestion                              Ingestion is the process of taking food in the body. Amoeba is a unicellular animal, so it doesn’t have a mouth for ingestion of food. Amoeba ingests the food by encircling it by forming pseudopodia. When the food is completely encircled , the food is engulfed in the form of a bag called food vacuole. Digestion: Digestion is the process of breaking the large and insoluble molecules in small and water soluble molecules. In amoeba, several digestive enzymes react on the food present in the food vacuoles and break it down into simple and soluble molecules. Absorption:                                            The food digested by digestive enzymes is then absorbed in the cytoplasm by the process of diffusion. While the undigested food remains in the food vacuole. If a large amount of food is absorbed by amoeba, the excess food is stored in the cytoplasm ih the form of glycogen and lipids.      Assimilation:                             During this step the food absorbed by the cytoplasm is used to obtain energy, growth and repair. This process of utilizing absorbed food for obtaining energy, repair and growth is called assimilation.        Egestion: When a sufficient amount of undigested food gets collected in the food vacuole, it is thrown out of the body by rupturing cell membrane. The process of removal of undigested food from the body is called egestion.                                                                                                                          

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List the advantages of vegetative propagation.

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List the advantages of vegetative propagation.

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Solution:
The advantages of vegetative propagation are as follows
• It helps in the easy propagation of ______________

• It helps in producing hybrids of various plants, with improved qualities.

• It helps in the propagation of a large number of populations in a very__________ duration.
• It helps in the propagation of plants that do not produce _____________ or produce them in very small quantities.