CBSE Class 10 Science Chapter 6 Life Processes
Respiration:
CBSE Class 10 Science Chapter 6 Life Processes Short Question And Answers
Question 1. How are the lungs designed in human beings to maximise the area for the exchange of gases?
Answer:
- The lungs are paired, and elastic respiratory organs are placed in the thoracic cavity.
- The trachea divides in the thoracic cavity into bronchi-the right and the left. Each bronchus divides into very small tubes called bronchioles.
- Each bronchiole terminates in balloon-like structures called alveoli.
- Each alveolus is thin-walled and is richly supplied by blood capillaries. Alveoli also provide maximum surface area for the exchange of gases.
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Question 2. What are the components of the transport system in human beings? What are the functions of these components?
Answer:
The transport system, called the circulatory system in human beings, mainly consists of the heart (pumping station), blood (fluid connective tissue) and blood vessels (in which blood flows).
- Heart: The heart is a muscular organ which is as big as our fist. The heart is a pumping organ to push blood around the body.
- It receives deoxygenated blood from the body parts and pumps it to lungs for to lungs for enriching with oxygen. It receives purified. blood from the lungs and pumps it around the body.
- Blood: Blood is fluid connective tissue. It consists of a fluid medium known as plasma in which the cells are suspended, such as white blood cells and red blood cells.
- Plasma transports food, carbon dioxide and nitrogenous wastes (urea and uric acid) in dissolved form.
- Red blood cells transport oxygen. Blood also transports many other Von substances like hormones, salt, etc. Platelets present in the blood stop bleeding from injuries by forming blood clots.
- Blood vessels: Blood vessels form a closed network of tubes to reach all the tissues. Thus, the blood pushed by the heart flows in the blood vessels (arteries) and also comes back to the heart back to the heart in the blood vessels (veins).
Question 3. Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
Answer:
The separation of oxygenated and deoxygenated blood from mixing allows a highly efficient supply of oxygen to the body. This is useful in animals that have energy needs such as efficient mams and birds. They constantly use energy to maintain their body temperature.
Question 4. What are the components of the transport system in highly organised plants?
Answer:
In higher plants transport system consists of vascular bundles which contain complex conducting tissues:
- Xylem which contains vessels tracheids, sclerenchyma (all dead tissues) and living xylem parenchyma. Vessels and tracheids form tubular structures and conduct water and dissolved minerals from roots to other parts.
- Phloem which contains sieve tubes, companion cells, phloem sclerenchyma and phloem parenchyma. Sieve tubes and companion cells conduct prepared food from leaves to other parts of the plant.
Question 5. How are water and minerals transported in plants? Lean abortion
Answer:
- The xylem conducts water and dissolved minerals through channels formed by tracheids. and vessels from roots to all parts of the plant body.
- The root cells actively take up ions from the soil causing steady movement of water into the root xylem. This inward flow of water pushes water upward with pressure, called root pressure. Transport of water by root pressure is more important at night, to log especially in small plants.
- Evaporation of water molecules from the cells of a leaf, called transpiration, creates a suction which pulls water from the xylem of roots. Thus, transpiration helps in the absorption and upward movement of water and dissolved minerals from the roots to the leaves in tall plants.
Question 6. How is food transported in plants?
Answer:
Transportation of prepared food such as carbohydrates, amino acid, etc., through the phloem from leaves to all parts of plants, is called translocation. Companion cells and sieve boron tubes conduct prepared food.
The mechanism of translocation is an active process and utilizes energy. Material like sucrose is transferred from leaf cells or the site of storage into phloem tissue. This process requires energy which is provided by ATP (adenosine triphosphate) molecules.
- Entry of sucrose into phloem tissue causes an increase in osmotic pressure. As a result water from outside moves into the phloem. The osmotic’ pressure moves the dissolved material in the phloem to tissues which have less pressure.
- Thus, material moves in phloem, mainly in sieve tubes, to the place of need in the plant body. For example, sugar is translocated from its storage organ, root or stem to growing buds which need energy.
Question 7. Describe the structure and functioning of nephrons.
Answer:
Structure of nephron: A nephron is the basic unit of filtration. A large number of nephrons are closely packed in the kidney.
- Each nephron consists of a cluster of very thin-walled blood capillaries called Glomerulus. Glomerulus is associated with the cup-shaped structure present at the end of a tubule.
- Thus, a nephron consists of a cluster of glomerulus which is a cluster of blood capillaries, a thin-walled Bowman’s capsule to collect the suig of sto filtrate and a long tubule which reabsorbs useful substances and also carries remaining urine to the collecting duct.
- Remove excess water, wastes and other substances from your blood.
- Return substances like sodium, potassium or phosphorus whenever only of these substances run low in our body.
Question 8. What are the differences between the transport of materials in the xylem and phloem?
Answer:
Question 9. Compare the functioning of alveoli in the lungs and nephrons in the kidneys concerning their structure and functioning.
Answer:
Question 10.
- What happens to the heart when muscles work harder?
- Which body system is directly affected when a person has heart disease?
- Which cells increase in number during infection?
Answer:
- When muscles work harder, they need more oxygen. So, the heart begins to pump blood faster to overcome that need.
- The circulatory system is directly affected when a person has heart disease.
- The number of white blood corpuscles (WBCs) increases during infection.
Question 11.
- Label any 4 parts in the given diagram.
- What are the two functions represented in this diagram?
Answer:
- Pulmonary artery to lungs
- Lung capillaries
- Pulmonary vein from lungs
- Aorta to body
- Capillaries in body organs
- Vena cava from the body.
- The two functions represented are:
- Transport of oxygen and carbon dioxide
- Exchange of oxygen and carbon dioxide
Question 12. What is blood pressure? How is it measured? Give one difference between systolic pressure and diastolic pressure.
Answer:
Blood Pressure: It is the force that blood exerts against the wall of a vessel. This pressure is much greater in arteries than in veins.
- It is measured using an instrument called a sphygmomanometer.
- The pressure of blood inside the artery during contraction or ventricular systole is called systolic pressure and pressure in the artery during relaxation or ventricular diastole is called diastolic pressure.
- The normal systolic pressure is about 120 mm of Hg and diastolic pressure is 80 mm of Hg.
Question 13. Draw a diagram of the human excretory system and label kidney and ureters on it.
Answer:
Question 14. Explain the mechanism of gaseous exchange between tissues and blood.
Answer:
The exchange of respiratory gases, i.e., oxygen and carbon dioxide, occurs between the blood and tissues.
- In tissues, oxygen is used up for their activities and carbon dioxide is released. The blood from the lungs has a high concentration of oxygen and a low concentration of carbon dioxide.
- Due to this difference in concentration of oxygen and carbon dioxide, the exchange of gases takes place between tissue and blood.
Question 15. Draw a schematic diagram to show the opening and closing of the stoma.
Answer:
Question 16.
- Write the balanced chemical equation for the process of photosynthesis.
- When do the desert plants take up carbon dioxide and perform photosynthesis?
Answer:
- 6CO2 + 6H2O→ C6H12O6 + 6O2
- Desert plants take up CO2 during the night. The CO2 is stored in organic acid at night and photosynthesis takes place during day time in the presence of sunlight.
Question 17. State in brief the function of:
- Renal artery
- Ureter
- Kidney
- Urinary bladder
Answer:
- Renal artery: It brings blood to the kidney for filtering waste.
- Kidney: It filters the blood and forms urine.
- Ureter: It passes urine from the kidneys to the urinary bladder.
- Urinary bladder: It stores the urine until it is released through the urethra.
Question 18. Draw a neat labelled diagram of the structure of a chloroplast.
Answer:
Question 19. What will happen if:
- Peristaltic movements do not occur all along the oesophagus.
- There are no platelets in the blood.
- Rings of cartilage are not present in the trachea.
Answer:
- If peristaltic movements do not occur, the food will not be able to be pushed forward, into the stomach.
- In case of no platelets, blood will not clot during bleeding.
- In the absence of rings of cartilage, air passage will collapse.
Question 20.
- Name the following:
- The part where the air is filtered by fine hair and mucus.
- The part which terminates in balloon-like structures.
- Balloon-like structures where the exchange of gases takes place. part which separates the chest cavity from the abdominal cavity.
- Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?
Answer:
- Nasal passage
- Bronchioles
- Alveoli
- Diaphragm.
- Since the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that in terrestrial organisms.
Question 21. What is lymph? How is the composition of lymph different from blood plasma? What is the direction of its flow? List two functions of the lymphatic system.
Answer:
Lymph is a circulatory fluid which flows in the lymphatic capillaries which join to form large lymph vessels.
Composition of Lymph:
Lymph is colourless and contains less protein than plasma.
Lymph flows from tissues to the heart.
Functions:
- Lymph carries digested and absorbed fat from the intestine.
- It drains excess fluid from extracellular space back into the blood.
Question 22.
- Why does a piece of bread taste sweet when chewed for some time?
- Cellulose acts as roughage in man but serves as a source of nutrients in cows. Justify the statement.
Answer:
- The saliva present in the mouth contains an enzyme called salivary amylase which breaks down starch present in the bread into sugar. That is why, a piece of bread tastes sweet when chewed for some time.
- Cellulose requires time to digest. Herbivore animals like cows have longer intestines which allows cellulose to be digested whereas human beings have comparatively short intestines. Thus, it is not digested and serves merely as roughage.
Question 23. List the three kinds of blood vessels of the human circulatory system and write their functions in tabular form.
Answer:
Question 24.
- A product is formed in our muscles due to the breakdown of glucose when there is a lack of oxygen. Name the product and also mention the effect of the build up of this product.
- Differentiate between fermentation in yeast and aerobic respiration based on end products formed.
Answer:
- Lactic acid is formed. The formation of lactic acid in the muscles causes cramps.
- During fermentation in yeast, ethanol is formed while in aerobic respiration, carbon dioxide and water are formed. The energy (ATP) released in the process of fermentation is also very low compared to aerobic respiration.
Question 25. Name the glands associated with the digestion of starch in the human digestive tract and mention their role. How is the required pH maintained in the stomach and small intestine?
Answer:
- Salivary glands – salivary amylase breaks starch into sugar.
- Pancreas – pancreatic amylase (juice) digests starch.
- Intestinal glands – intestinal amylase – digests starch.
- Acidic pH in the stomach – due to Hydrochloric acid secreted by the stomach.
- Alkaline pH in small intestine – due to bile (liver)/pancreatic juice (pancreas).
Question 26. Name the two glands associated with the digestive system in humans Name their secretion also.
Answer:
- Gastric glands: These are present in the walls of the stomach. These release HCl, a protein-digesting enzyme called pepsin and mucus.
- Pancreatic enzymes: The pancreas secretes pancreatic juice which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats.
Question 27. What are the final products produced after digestion of carbohydrates, proteins and fats?
Answer:
- Carbohydrates – glucose
- Proteins – amino acid
- Fats glycerol + fatty acid
Question 28. Name the following concerning the alimentary canal:
- The largest gland.
- The gland secretes digestive enzymes as well as hormones.
- The part where digested food is absorbed.
- What are villi? Mention their function.
Answer:
- Liver
- Pancreas
- Small intestine
- Numerous finger-like projections present in the inner lining of the intestine which increase the surface area for absorption.
Function: These absorb digested food in the small intestine and absorb water in the large intestine.
Question 29. What are the common features of the respiratory organs in aquatic and terrestrial animals?
Answer:
- Large surface area
- Thin-walled
- Richly supplied with blood
- Well protected.
Question 30. Where do the following processes take place?
- Filtration of blood
- Reabsorption of glucose and water
- Secretion of salts to make final filtrate
- Collection of the final filtrate.
Answer:
- Glomerulus
- Renal tubules
- Tubular cells
- Collecting duct
Question 31. Explain how Paramecium obtains its food.
Answer:
In Paramecium, the food is taken in at a specific spot and is moved to this spot by the movement of cilia which covers the entire surface of the cell.
Question 32. Assume that you are a veterinary surgeon and you have removed a good length of the small intestine of a bear that was suffering from an intestinal tumour. Now, would you suggest a plant-based or a meat-based diet for the bear after its recovery? Give reasons for your answer.
Answer:
I would suggest a meat-based diet. Because to digest a plant-based diet, the bear will need a longer small intestine, since the cellulose present in the plant diet requires a longer time for digestion.
Question 33.
- Name the following:
- Part in which urine is produced
- The part which stores the urine
- The part which connects 1 and 2
- A part from which urine is passed out.
- Name the factors on which the amount of water reabsorbed along the tubular part of the nephron depends.
Answer:
- Kidney
- Ureter
- Urinary bladder
- Urethra,
- The amount of water reabsorbed depends on how much excess water there is in the body and on how much-dissolved waste there is to be excreted.
Question 34. State two functions of stomata.
Answer:
A massive amount of gaseous exchanges takes place in leaves through stomata. Large amounts of water can be lost through stomata (transpiration).
Question 35.
- Name the following:
- The organ which stores bile
- The organ which produces bile
- Name one enzyme present in pancreatic juice and write its functions.
- What are peristaltic movements?
Answer:
- Gall bladder
- Liver
- Trypsin: Digests proteins into amino acids.
- Amylase: Digests carbohydrates into simple sugars.
- Lipase: Digests fats into fatty acids and glycerol.
- The lining of the alimentary canal has muscles that contract rhythmically to push food forward. These are known as peristaltic movements.
Question 36. Define transpiration. State its two functions.
Answer: The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration.
Functions:
- It helps in the absorption and upward movement of water and minerals dissolved in it from roots to the leaves.
- It also helps in temperature regulation.
Question 37. How would digestion of food be affected if the bile duct is completely blocked?
Answer: If the bile duct is completely blocked, bile juice will not reach the small intestine and the digestion of fats will be affected.
Question 38. 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. In the mouth, food gets mixed up with saliva secreted by salivary glands. Saliva contains an enzyme called salivary amylase which breaks polysaccharide starch into disaccharide maltose (sugar).
Question 39. Distinguish between saprozoic and holozoic nutrition.
Answer:
Question 40. What are the final products after the digestion of carbohydrates and proteins?
Answer:
The final product produced after digestion of carbohydrates is glucose and that of proteins is amino acid.
Question 41. Explain the process of nutrition in Amoeba.
Answer:
The mode of nutrition in Amoeba is holozoic. It feeds on unicellular plants or animals. The various steps of nutrition are ingestion, digestion, assimilation and egestion.
- When Amoeba comes in contact with food particles, they send out pseudopodia, which engulf the prey by forming a food cup, which is known as ingestion.
- When the tips of the encircling pseudopodia touch each other, the food is encaptured into a bag called a food vacuole. Various enzymes from the cytoplasm enter the food vacuole and break them down into simple soluble molecules.
- This food is then absorbed by the cytoplasm of Amoeba through the process of diffusion. Amoeba cell obtains energy from the absorbed food. The undigested food is thrown out from its cell membrane.
Question 42. Name the following
- The process in plants that links light energy with chemical energy
- Organisms that can prepare their food
- The cell organelle where photosynthesis occurs
- Cells that surround a stomatal pore
- Organisms that cannot prepare their food
- An enzyme secreted from gastric glands in the stomach that acts on proteins.
Answer:
- Photosynthesis
- Autotrophs
- Chloroplast
- Guard cells
- Heterotrophs
Question 43. “All plants give out oxygen during the day and carbon dioxide during the night”. Do you agree with this statement? Give reason.
Answer:
During this time, as the rate of photosynthesis is more than the rate of respiration, the next result is the evolution of oxygen. At night there is no photosynthesis, so, they give out carbon dioxide due to respiration.
Question 44. How do the guard cells regulate the opening and closing of stomatal pores?
Answer:
The swelling of guard cells due to the absorption of water causes the opening of stomatal pores while the shrinking of guard cells closes the pores. Opening and closing of stomata occurs due to turgor changes in guard cells.
When guard cells are turgid, the stomatal pore is open while in flaccid conditions, the stomatal aperture closes.
Question 45. Two green plants are kept separately in oxygen-free containers, one in the dark and the other in continuous light. Which one will live longer? Give reasons.
Answer:
Plants kept in continuous light will live longer because they will be able to produce the oxygen required for their respiration through the process of photosynthesis.
Question 46. If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring? Justify your answer.
Answer:
Release of CO2 and intake of O2 gives evidence that either photosynthesis is not taking place or its rate is too low. Normally during the daytime, the rate of photosynthesis is much more than the rate of respiration. So, CO2 produced during respiration is used up for photosynthesis hence CO2 is not released.
Question 47. Why do fishes die when taken out of water?
Answer:
Fishes respire with the help of gills. Gills are richly supplied with blood capillaries and can readily absorb oxygen dissolved in water. Since fishes cannot absorb gaseous oxygen they die soon after they are taken out of water.
Question 48. Differentiate between an autotroph and a heterotroph.
Answer:
Question 49. Is ‘nutrition’ a necessity for an organism? Discuss.
Answer:
Food is required for the following purposes:
- It provides energy for the various metabolic processes in the body.
- It is essential for the growth of new cells and the repair or replacement of worn-out cells.
- It is needed to develop resistance against various diseases.
Question 50. What would happen if green plants disappeared from Earth?
Answer:
Green plants are the sources of energy for all organisms. If all green plants disappear from the earth, all the herbivores will die due to starvation and so will the carnivores.
Question 51. Leaves of a healthy potted plant were coated with Vaseline. Will this plant remain healthy for long? Give reasons for your answer.
Answer:
This plant will not remain healthy for a long time because
- It will not get oxygen for respiration.
- It will not get carbon dioxide for photosynthesis.
- The upward movement of water and minerals would be hampered due to lack of transpiration.
Question 52. How does aerobic respiration differ from anaerobic respiration?
Answer:
Question 53. Match the words of Column with that of Column
Answer:
- 2
- 1
- 4
- 3
Question 54. Differentiate between an artery and a vein.
Answer:
Question 55. What are the adaptations of leaves for photosynthesis?
Answer:
- Leaves provide a large surface area for maximum light absorption.
- Leaves are arranged at right angles to the light source in a way that causes overlapping.
- The extensive network of veins enables quick transport of substances to and from the mesophyll cells.
- Presence of numerous stomata for gaseous exchange.
- The chloroplasts are more in number on the upper surface of leaves.
Question 56. Why is the small intestine in herbivores longer than in 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, hence they have a shorter intestine.
Question 57. What will happen if mucus is not secreted by the gastric glands?
Answer:
Gastric glands in the stomach release hydrochloric acid, enzyme pepsin and mucus. The mucus protects the inner lining of the stomach from the action of hydrochloric acid and enzyme pepsin.
If the mucus is not released, it will lead to erosion of the inner lining of the stomach, leading to acidity and ulcers.
Question 58. What is the significance of the emulsification of fats?
Answer:
Fats are present in food in the form of large globules which makes it difficult for enzymes to act on them. Bile salts present in bile break them down mechanically into smaller globules which increases the efficiency of fat digesting enzymes.
Question 59. What causes the movement of food inside the alimentary canal?
Answer:
The wall of the alimentary canal contains muscle layers. Rhythmic contraction and relaxation of these muscles push the food forward. This is called peristalsis, which occurs all along the gut.
Question 60. Why does absorption of digested food occur mainly in the small intestine?
Answer:
Maximum absorption occurs in the small intestine because
- Digestion is completed in small intestine
- The inner lining of the small intestine is provided with villi which increases the surface area for absorption.
- The wall of the intestine is richly supplied with blood vessels (which take the absorbed food to every cell of the body).
Question 61. Match Group (A) with Group (B)
Answer:
- D
- C
- A
- B
Question 62. Why is the rate of breathing in aquatic organisms much faster than in terrestrial organisms?
Answer:
Aquatic organisms like fishes obtain oxygen from water present in a dissolved state through their gills. Since the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms.
Question 63. Why is blood circulation in the human heart called double circulation?
Answer:
The blood circulation in the human heart is called double circulation because the blood passes through the heart twice in one complete cycle of the body – once through the right half in the form of deoxygenated blood and once through the left half in the form of oxygenated blood.
Question 64. What is the advantage of having a four-chambered heart?
Answer:
In a four-chambered heart, the left half is completely separated from the right half by septa. This prevents oxygenated and deoxygenated blood from mixing.
This allows a highly efficient supply of oxygenated blood to all parts of the body. This is useful in animals that have high energy needs, such as birds and mammals.
Question 65. Mention the major events during photosynthesis.
Answer:
The major events during photosynthesis are:
- Absorption of light energy by chlorophyll
- Conversion of light energy to chemical energy
- Splitting of H2O into H2, O2 and eTM
- Reduction of CO2 to carbohydrates
Question 66. In each of the following situations, what happens to the rate of photosynthesis?
- Cloudy days
- No rainfall in the area
- Good manuring in the area
- Stomata get blocked due to dust
Answer:
- Decreases.
- Decreases.
- Increases.
- Decreases.
Question 67. Name the energy currency in the living organisms. When and where is it produced?
Answer:
Adenosine triphosphate (ATP) is produced during respiration in living organisms and also during photosynthesis in plants.
Question 68. What is common for Cuscuta; ticks and leeches?
Answer:
All are parasites, they derive nutrition from plants or animals without killing them.
Question 69. Explain the role of the mouth in the digestion of food.
Answer:
- Food is crushed into small pieces by the teeth.
- It mixes with saliva and the enzyme amylase (found in saliva) breaks down starch into sugars.
- The tongue helps in the thorough mixing of food with saliva.
Question 70. What are the functions of gastric glands present in the wall of the stomach?
Answer:
- Production of pepsin enzyme that digests proteins
- Secretion of mucus for protection of the inner lining of the stomach.
Question 71. Match the terms in Column (A) with those in Column (B)
Answer:
- A
- D
- B
- C
Question 72. Name the correct substrates for the following enzymes:
- Trypsin
- Amylase
- Pepsin
- Lipase
Answer:
- Protein
- Starch
- Protein
- Fats
Question 73. Why do veins have thin walls as compared to arteries?
Answer:
Arteries carry blood from the heart to various organs of the body under high pressure so they have thick and elastic walls. Veins collect the blood from different organs and bring it back to the heart.
The blood is no longer under pressure so the walls are thin with valves to ensure that blood flows only in one direction.
Question 74. What will happen if platelets are absent in the blood?
Answer: In the absence of platelets, the process of clotting will be affected.
Question 75. Plants have low energy needs as compared to animals. Explain.
Answer: Plants do not move. In a large plant body, there are many dead cells like sclerenchyma, as a result, it requires less energy as compared to animals.
Question 76. Why and how does water enter continuously into the root xylem?
Answer:
Cells of the root are in close contact with soil and so actively take up ions. The ion- concentration increases inside the root and hence osmotic pressure increases the movement of water from the soil into the root which occurs continuously.
Question 77. Why is transpiration important for plants?
Answer:
Transpiration is important because
- It helps in the absorption and upward movement of water and minerals from roots to leaves.
- It prevents the plant parts from heating up.
Question 78. How do the leaves of plants help in excretion?
Answer:
Many plants store waste materials in the vacuoles of mesophyll cells and epidermal cells. When old leaves fall, the waste materials are excreted along with the leaves.
Question 79. What is the functional difference between the four chambers of the heart?
Answer:
Question 80. Give one structural and one functional difference between an artery and a vein.
Answer:
Question 81. Give the role of the following in plants and animals:
- Guard cells
- Hymph
- Bio catalyst
- Phloem
Answer:
- Stomatal opening
- Fat transport
- Speeding up the digestive process
- Transport of food
Question 82. Name the excretory wastes of the following:
- Lungs
- Kidney
- Skin
- Leaves.
Answer:
- CO2
- Urea
- Sweat
- O2, H2O and CO2
Question 83. After a vigorous exercise, you may experience cramps in your leg muscles. Why does this happen?
Answer:
This happens due to the build-up of lactic acid in our muscles. During heavy exercise, there is a lack of oxygen in our muscle cells and therefore, another pathway for the breakdown of pyruvate of lactic acid takes place.
Question 84. Which organ secretes a hormone when the blood sugar rises? Name the digestive enzymes released by this organ.
Answer:
The pancreas secretes the hormone insulin which regulates the blood sugar level. Digestive enzymes secreted by the pancreas are trypsin and lipase.
Question 85. Explain the assimilation of carbohydrates, proteins and fats inside the cells.
Answer:
- Carbohydrates: Glucose is used to release energy. Excess of glucose is brought to the liver and converted to glycogen (glycogenesis) and stored there. As the need arises the glucose is reformed from glycogen (glycogenolysis) and released into the bloodstream.
- Proteins: Most of the amino acids are used in protein synthesis which helps in the growth and repair of body tissues. Proteins may act as structural proteins or act as enzymes and thus control various metabolic activities of the body.
- Amino acids which are not used as such, are deaminated in the liver i.e., the amino group (-NH2) is removed. The amino group forms ammonia (NH3) which is highly toxic and must be removed. This is done by liver cells which convert it to harmless urea, which is then a Diagram showing absorption of food in the intestine excreted by the kidneys. Urea is formed only in the liver.
- Fats: Fats release energy. Excess fats are stored in the liver and the form of adipose tissue. Some fats enter into the composition of cell organelles.
Question 86. For the last few days Rakesh has started cycling long distances. But on his way back he feels cramps in his calf muscles.
- What can be the possible cause of it?
- Name the process involved and its equation.
- How can Rakesh have quick relief from muscle cramps?
Answer:
1. Accumulation of lactic acid in the muscles.
2. Anaerobic respiration.
3. By having lots of water baths and a massage.
Question 87. During sports practice in the school, many students got tired very soon and were found to be anaemic. Health and Wellness group students made a presentation on the ‘right diet for right health’ and uploaded it on school website.
- What causes anaemia?
- Name two foods that can help to overcome the problem of anaemia.
- What value of Health and Wellness group students is displayed in the above act?
Answer:
- A deficiency of haemoglobin in red blood cells leads to anaemia.
- Spinach and beetroot.
- Health and Wellness group students showed the value of group work and being responsible citizens.
Question 88. A group of students from class X were given the project on ‘respiratory diseases’. The students spread an awareness camp on how to overcome respiratory problems.
- What are the causes of respiratory diseases?
- Name two respiratory diseases.
- What value of students of class X is displayed in the above act?
Answer:
- Too small and suspended particles inhaled causing respiratory diseases.
- Asthma and bronchitis.
- Students of class X showed the value of group work, being cooperative learners and responsible citizens.
Life Processes Multiple Choice Questions
1. Which of the following statements about the autotrophs is incorrect?
- They synthesise carbohydrates from carbon dioxide and water in the presence of sunlight and chlorophyll
- They store carbohydrates in the form of starch
- They convert carbon dioxide and water into carbohydrates in the absence of sunlight
- They constitute the first trophic level in food chains
Answer: 3. They convert carbon dioxide and water into carbohydrates in the absence of sunlight
2. In which of the following groups of organisms, food material is broken down outside the body and absorbed?
- Mushrooms, green plants, Amoeba
- Yeast, mushroom, bread mould
- Paramecium, Amoeba, Cuscuta
- Cuscuta, lice, tapeworm
Answer: 2. Yeast, mushroom, bread mould
3. Select the correct statement
- Heterotrophs do not synthesise their food
- Heterotrophs utilise solar energy for photosynthesis
- Heterotrophs synthesise their food
- Heterotrophs are capable of converting carbon dioxide and water into carbohydrates
Answer: 1. Heterotrophs do not synthesise their food
4. Which is the correct sequence of parts in the human alimentary canal?
- Mouth → stomach → small intestine → oesophagus → large intestine
- Mouth → oesophagus → stomach → large intestine → small intestine
- Mouth → stomach → oesophagus → small intestine → large intestine
- Mouth → oesophagus → stomach → small intestine → large intestine
Answer: 4. Mouth → oesophagus → stomach → small intestine → large intestine
5. If salivary amylase is lacking in the saliva, which of the following events in the mouth cavity will be affected?
- Proteins breaking down into amino acids
- Starch breaking down into sugars
- Fats breaking down into fatty acids and glycerol
- Absorption of vitamins
Answer: 2. Starch breaking down into sugars
6. The inner lining of the stomach is protected by one of the following from hydrochloric acid. Choose the correct one
- Pepsin
- Mucus
- Salivary amylase
- Bile
Answer: 2. Mucus
7. Which part of the alimentary canal receives bile from the liver?
- Stomach
- Large intestine
- Small intestine
- Oesophagus
Answer: 2. Large intestine
8. A few drops of iodine solution were added to rice water. The solution turned blue-black. This indicates that rice water contains
- Complex proteins
- Simple proteins
- Fats
- Starch
Answer: 4. Starch
9. In which part of the alimentary canal food is finally digested?
- Stomach
- Mouth cavity
- Large intestine
- Small intestine
Answer: 4. Small intestine
10. Choose the function of the pancreatic juice from the following
- Trypsin digests proteins and lipase carbohydrates
- Trypsin digests emulsified fats and lipase proteins
- Trypsin and lipase digest fats
- Trypsin digests proteins and lipase-emulsified fats
Answer: 4. Trypsin digests proteins and lipase-emulsified fats
11. When air is blown from the mouth into a test tube containing lime water, the lime water turns milky due to the presence of
- Oxygen
- Carbon dioxide
- Nitrogen
- Water vapour
Answer: 2. Carbon dioxide
12. The correct sequence of anaerobic reactions in yeast is
Answer: 4.
13. Which of the following is most appropriate for aerobic respiration?
Answer: 4.
14. Which of the following statement(s) is (are) true about respiration?
- During inhalation, ribs move inward and the diaphragm is raised
- In the alveoli, an exchange of gases takes place i.e., oxygen from alveolar air diffuses into blood and carbon dioxide from blood into alveolar air
- Haemoglobin has a greater affinity for carbon dioxide than oxygen
- Alveoli increase surface area for the exchange of gases
- 1 and 4
- 1 and 3
- 2 and 3
- 2 and 4
Answer: 4. 2 and 4
15. Which is the correct sequence of air passage during inhalation?
- Nostrils → larynx → pharynx → trachea → lungs
- Nasal passage → trachea → pharynx → larynx → alveoli
- larynx → nostrils → pharynx → lungs
- Nostrils → pharynx → larynx → trachea → alveoli
Answer: 4. Nostrils → pharynx → larynx → trachea → alveoli
16. During respiration exchange of gases takes place in
- Trachea and larynx
- Alveoli of lungs
- Alveoli and throat
- Throat and larynx
Answer: 2. Alveoli of lungs
17. Which of the following statement(s) is (are) true about heart?
- The left atrium receives oxygenated blood from different parts of the body while the right atrium receives deoxygenated blood from the lungs
- The left ventricle pumps oxygenated blood to different body parts while the right ventricle pumps deoxygenated blood to the lungs
- The left atrium transfers oxygenated blood to the right ventricle which sends it to different body parts
- Right atrium receives deoxygenated blood from different parts of the body while the left ventricle pumps oxygenated blood to different parts of the body
- 1
- 2
- 2 and 4
- 1 and 3
Answer: 3. 2 and 4
18. What prevents the backflow of blood inside the heart during contraction?
- Valves in heart
- Thick muscular walls of ventricles
- Thin walls of atria
- All of the above
Answer: 1. Valves in the heart
19. Single circulation i.e., blood flows through the heart only once during one cycle of passage through the body, is exhibited by
- Labeo, Chameleon, Salamander
- Hippocampus, Exocoetus, Anabas
- Hyla, Rana, Draco
- Whale, Dolphin, Turtle
Answer: 2. Hippocampus, Exocoetus, Anabas
20. In which of the following vertebrate groups/groups, the heart does not pump oxygenated blood to different parts of the body?
- Pisces and amphibians
- Amphibians and reptiles
- Amphibians only
- Pisces only
Answer: 4. Pisces only
21. Choose the correct statement that describes arteries.
- They have thick elastic walls, blood flows under high pressure; collect blood from different organs and bring it back to the heart
- They have thin walls with valves inside, blood flows under low pressure and carry blood away from the heart to various organs of the body
- They have thick elastic walls, blood flows under low pressure; and carry blood from the heart to various organs of the body
- They have thick elastic walls without valves inside, blood flows under high pressure and carries blood away from the heart to different parts of the body.
Answer: 4. They have thick elastic walls without valves inside, blood flows under high pressure and carries blood away from the heart to different parts of the body.
22. The filtration units of kidneys are called
- Ureter
- Urethra
- Neurons
- Nephrons
Answer: 4. Nephrons
23. Oxygen liberated during photosynthesis comes from
- Water
- Chlorophyll
- Carbon dioxide
- Glucose
Answer: 1. Water
24. The blood leaving the tissues becomes richer in
- Carbon dioxide
- Water
- Haemoglobin
- Oxygen
Answer: 1. Carbon dioxide
25. Which of the following is an incorrect statement?
- Organisms grow with time
- Organisms must repair and maintain their structure
- The movement of molecules does not take place among cells
- Energy is essential for life processes
Answer: 3. Movement of molecules does not take place among cells
26. The internal (cellular) energy reserve in autotrophs is
- Glycogen
- Protein
- Starch
- Fatty acid
Answer: 3. Starch
27. Which of the following equations is the summary of photosynthesis?
- 6CO2+ 12H2O → C6H12O6+ 6O2+ 6H2O
- 6CO2 + H2O + Sunlight → C6H12O6 + O2+ 6H2O
- 6CO2 + 12H2O + Chlorophyll + Sunlight → C6H12O6 + 6O2+ 6H2O
- 6CO2 + 12H2O + Chlorophyll + Sunlight → C6H12O6+6CO2+ 6H2O
Answer: 3. 6CO2 + 12H2O + Chlorophyll + Sunlight → C6H12O6 + 6O2+ 6H2O
28. Choose the event that does not occur in photosynthesis
- Absorption of light energy by chlorophyll
- Reduction of carbon dioxide to carbohydrates
- Oxidation of carbon to carbon dioxide
- Conversion of light energy to chemical energy
Answer: 3. Oxidation of carbon to carbon dioxide
29. The opening and closing of the stomatal pore depends upon
- Oxygen
- Temperature
- Water in guard cells
- The concentration of CO2 in stomata
Answer: 3. Water in guard cells
30. Choose the forms in which most plants absorb nitrogen
- Proteins
- Nitrates and Nitrites
- Urea
- Atmospheric nitrogen
- 1 and 2
- 2 and 3
- 3 and 4
- 1 and 4
Answer: 2. 2 and 3
31. Which is the first enzyme to mix with food in the digestive tract?
- Pepsin
- Cellulase
- Amylase
- Trypsin
Answer: 3. Amylase
32. Which of the following statement(s) is (are) correct?
- Pyruvate can be converted into ethanol and carbon dioxide by yeast
- Fermentation takes place in aerobic bacteria
- Fermentation takes place in mitochondria
- Fermentation is a form of anaerobic respiration
- 1 and 3
- 2 and 4
- 1 and 4
- 2 and 3
Answer: 3. 1 and 4
33. Lack of oxygen in muscles often leads to cramps among cricketers. This results due to
- Conversion of pyruvate to ethanol
- Conversion of pyruvate to glucose
- Non-conversion of glucose to pyruvate
- Conversion of pyruvate to lactic acid
Answer: 4. Conversion of pyruvate to lactic acid
34. Choose the correct path of urine in our body
- Kidney → ureter → urethra → urinary bladder
- Kidney → urinary bladder → urethra → ureter
- Kidney → ureters → urinary bladder → urethra
- Urinary bladder → kidney → ureter → urethra
Answer: 3. Kidney → ureters → urinary bladder → urethra
35. During deficiency of oxygen in tissues of human beings, pyruvic acid is converted into lactic acid in the
- Cytoplasm
- Chloroplast
- Mitochondria
- Golgi body
Answer: 1. Cytoplasm