Multiple Choice Questions
1. The correct statement regarding digestion that takes place in the small intestine is
A. Acidic food becomes alkaline due to bile.
B. Food becomes acidic due to hydrochloric acid.
C. Starch is digested by the action of amylase.
D. Protein is digested by the action of pepsin.
Ans: A) Acidic food becomes alkaline due to bile.
2. The place where carbohydrates, proteins and fats are completely digested.
A. Stomach B. Large intestine
C. Small intestine D. Liver
Ans: C) Small intestine
3. Blood vessels that carry blood from all parts of the human body to the heart
A. Arteries B. Capillaries
C. Pulmonary arteries D. Veins
Ans: D) veins
4. Blood vessels in the human body that carry deoxygenated blood from the heart to the lungs.
A. Pulmonary veins B. Aorta
C. Pulmonary arteries D. Veins
Ans: D) pulmonary arteries
5. Transport of soluble photosynthesis products in plants
A. Evaporation B. Osmosis
C. Diffusion D. Translocation
Ans: D. Translocation
6. Important function of xylem in plants
A. Water transport
B. Food transport
C. Amino acid transport
D. Oxygen transport
Ans: A) Water transport
7. The main function of the kidney in humans is
A. Nutrition B. Respiration
C. Excretion D. Transport
Ans: C) Excretion
8. The place where carbon dioxide and water are released from the breakdown of pyruvate is
A. cytoplasm B. mitochondria
C. chloroplast D. nucleus
Ans: B) Mitochondria
9. Which of the following is a function of the kidney?
A. Excretion of undigested food materials
B. Excretion of urea in the form of urine
C. Excretion of carbon dioxide
D. Production of hormones
Ans: B) Excretion of urea in urine
10. Function of stomata.
A. Exchange of gases
B. Transport of water
C. Transport of food
D. Transport of oxygen
Ans: Exchange of gases
11. Structural and functional unit of Kidney is
A. Neuron B. Nephron
C. Cell D. Muscle cell
Ans: B) Nephron
12. A colourless, low-protein fluid in the circulatory system is
A. Red blood cells B. Plasma
C. Lymph D. Platelets
Ans: C) Lymph
13. The blood vessel that carries oxygenated blood from the heart is
A. Pulmonary vein B. Aorta
C. Superior vena cava D. Small vessel
Ans: C) Aorta
14. The important role of stomata in photosynthesis is
A. Creating upward tension
B. Absorbing carbon dioxide
C. Releasing oxygen
D. Continuous transpiration.
Ans: B. Absorbing carbon dioxide
15. Part of the excretory system that stores nitrogenous wastes dissolved in water
A. Kidney B. Ureter
C. Urinary bladder D. Urethra
Ans: C) Urinary bladder
16. Transpiration process in plant body
A. Balancing the amount of oxygen and water
B. To establish a water column in the xylem tissue
C. To help in the transport of soluble photosynthesis products
D. To create osmotic pressure
Ans: B. To establish a water column in the xylem tissue
17. Plants release excess water through this process.
A. Transpiration B. Photosynthesis
C. Respiration D. Metabolism
Ans: Transpiration
18. The need for suction pressure in plants is,
A. To overcome the difference in ion concentration between the root and the soil
B. To transport food in two directions
C. To carry water to higher parts
D. To remove excess water from the leaves
Ans: C) To carry water to higher places
II. Answer the following questions (one mark questions)
19. When is lactic acid produced in muscle cells?
Ans: Lactic acid is produced when there is a lack of oxygen in muscle cells.
20. How is oxygen supply more efficient in birds and mammals?
Ans: The left and right sides of the heart are separated, so oxygenated and deoxygenated blood do not mix.
21. Name the products of anaerobic respiration.
Ans: In anaerobic respiration (in yeast cells), a molecule of glucose is broken down to produce ethanol and carbon dioxide
22. Why do deer and rabbits have longer small intestines than tigers/lions?
Ans: To digest cellulose
23. Why is the respiration rate of aquatic animals faster than that of terrestrial animals?
Ans: The amount of oxygen in water is less than the amount of oxygen in air. Therefore, aquatic organisms breathe faster to get more oxygen.
24. Write the function of the platelets.
Ans: Blood clots in injured areas and stops the leakage
25. Name the type of transport where food material transported from the leaves to other parts?
Ans: Translocation.
26. What is transpiration?
Ans: The loss of water in the form of vapor from plant parts exposed to the atmosphere is called transpiration
27. What is double circulation?
Ans: Blood passes through the heart twice.
28. What is excretion?
Ans: The process of remove waste products produced by metabolic processes from the body.
29. What is the function of guard cells?
Ans: The opening and closing of stomata.
30. When does stomata close?
Ans: The stomata close when carbon dioxide is not needed for photosynthesis.
31. What is the function of the air sacs or alveoli in the lungs?
Ans: The exchange of carbon dioxide and oxygen gases between the blood and the cells.
32. Osmotic pressure in the phloem tissues of plants helps in the transport of materials. Justify your answer
Ans: Osmotic pressure in plants causes materials to move from the phloem to tissues of lower pressure, thereby transporting food.
33. There is a time to absorb oxygen and release carbon dioxide at the beginning of respiration. Justify.
Ans: The lungs always retain a small amount of air as they inhale and exhale during the respiratory cycle.
34. What is the finger-like structures in the small intestine called?
Ans: Villi
35. Write the function of villi?
Ans: Villi increase the surface area needed to absorb digested food.
36. Humans can't digest grass like plants. Give Reason.
Ans: Because humans do not have the enzyme cellulase to digest starch or the enzyme to digest cellulose
37. Diffusion is not enough to meet the oxygen requirement in multicellular organisms Why?
Ans: In multicellular organisms, not all cells can be in contact with the surrounding environment.
38. Enzymes are biological catalysts. Justify.
Ans: Enzymes are called biological catalysts because they help in the conversion of complex food into simpler forms so that it can be absorbed by the digestive tract.
39. What are life processes?
Ans: The maintenance processes that take place in living organisms are called life processes
40. Name the two types of respiration
Ans: 1. Aerobic respiration 2. Anaerobic respiration
41. Name the product released when the 6-carbon molecule of glucose is broken down in cytoplasm?
Ans: Pyruvate
42. What is nutrition?
Ans: The process of consuming, digesting and utilizing food is called nutrition.
43. Name the two types of vascular tissues in plants
Ans: Xylem and Phloem
44. What is photosynthesis?
Ans: The process by which plants make food using carbon dioxide, water, sunlight, and chlorophyll is called photosynthesis
45. What is cellular respiration?
Ans: The process by which glucose reacts with oxygen in a cell to release energy.
46. What are parasites?
Ans: Organisms that depend on other organisms for their food are called parasitoids.
47. The haemoglobin content in the blood of two persons A and B is found to be 9gm/dl and 13 gm/dl respectively. Which statement is correct regarding the oxygen supply in their body?
A) More in Person A than in B
B) More in Person B than in A
Ans: A) Person A is more likely to be in B than in A
48. The schematic representation of blood circulation in the mammals is given below.
a) Name the blood vessels x and y.
b) Which blood vessel has a valve?
Ans:
a) x = artery y = vein
b) Veins have valves
49. State the importance of transpiration in plants.
Ans:
i) Excreting excess water in plants
ii) Helping in the upward movement of water
50. How does the transpiration process contributes to both transportation of water and excretion processes in plants?
Ans: It transports water by creating pressure for the upward movement of water through transpiration and excretes water through stomata.
III. Answer the following questions (two marks questions)
51. Draw the diagram of open stomata and label the parts.
Ans:
52. The approximate lengths of the small intestines of animals x and Y are given in the table. Observe the table and answer the questions
Identify the herbivorous and carnivorous animals in the table and support your conclusions with scientific reasons.
Ans:
★ Animal X = Herbivorous Animal
★ Animal Y = Carnivorous Animal
The length of the small intestine in herbivorous animals is longer than that in carnivorous animals
53. Chapati tastes sweeter when chewed slowly. Why?
Ans:
★ The saliva released while chewing chapati contains the enzyme amylase
★ This enzyme breaks down the starch in chapati and converts it into simple sugar.
54. Give reason:
a) The ventricles of the human heart have thick walls.
b) In mammals and birds, it is necessary to separate oxygenated and deoxygenated blood.
Ans:
a) Because the heart has to pump blood into several organs
b) Because it requires a lot of energy to maintain its body temperature.
55. Name the enzyme present in Saliva. Write its function.
Ans:
★ Amylase is an enzyme found in saliva.
★ Function: Breaks down the complex molecule starch and releases sugar.
56. Observe the pictures given below:
a) Which picture indicates a high rate of gas exchange? Why?
b) Name the parts X and Y and what is the function of the part X?
Ans:
a) Figure (1) / Open stomata Since stomata are open
b) X– Guard cell Y – Stomata
57. Draw a diagram of nephron and label the parts.
Ans:
58. What is the function of bile juice?
Ans:
★ Alkalizing food and
★ Breaking down large fat particles into smaller particles to increase the efficiency of enzymes
59. How are oxygen and carbon dioxide transported in humans?
Ans:
★ Hemoglobin in red blood cells has a high affinity for oxygen, which carries oxygen from the lungs to other parts of the body.
★ Carbon dioxide is more soluble in water than oxygen, so it is transported to the lungs through the blood plasma
60. The body temperature of frogs and lizards depends on the environment temperature. Justify.
Ans:
★ They have a three-chambered heart.
★ Oxygenated and deoxygenated blood mix to some extent.
61. Why does the heart have different chambers?
Ans:
★ Since both oxygen and carbon dioxide must be transported through the blood,
★ The heart has separate chambers to prevent oxygen-rich blood from mixing with carbon dioxide- depleted blood.
62. State the importance of double circulation.
Ans:
★ Double circulation helps in the rapid delivery of oxygenated blood to all parts of the body. This enables organisms to meet their high energy needs.
★ Double circulation in mammals and birds helps regulate body temperature
63. If humans had a three-chambered heart like a frog, then how would be the blood circulation?
Ans:
★ The blood circulation was incomplete, as pure and impure blood was mixed.
★ Double blood circulation was not observed
64. Herbivores like sheep have long small intestines, while animals like tigers have short small intestines. Write the reason for this difference?
Ans:
★ Herbivores that eat grass have a long small intestine to digest cellulose.
★ But carnivores like tigers digest meat easily. So carnivores have a short small intestine
65. Photosynthesis does not occur in plants growing in deserts as it does in normal plants. Give reason
Ans:
★ As plants growing in deserts face water scarcity, stomata close in the morning, preventing transpiration.
★ At night, they take in carbon dioxide and produce an intermediate substance, which is then absorbed by chlorophyll during the day, and the energy acts on this substance.
66. What is photosynthesis? What is the product released in this process? Write the function of this product.
Ans:
★ The process by which green plants make food using carbon dioxide and water with the help of sunlight and chlorophyll (a pigment in leaves) is called photosynthesis.
★ Carbohydrates | Glucose
★ Carbohydrates are used to meet energy needs in plants.
67. Lymph plays an important role in maintaining the body's immune system. Justify this statement.
Ans:
A) Produces antibodies.
B) Lymphocyte cells eliminate bacteria and unnecessary substances
68. Write the difference between arteries and veins.
Ans:
69. What is the role of hydrochloric acid in our stomach?
Ans:
★ Creates an acidic environment to promote the action of the enzyme pepsin.
★ Destroys microorganisms that enter the stomach with food.
70. How does ATP synthesize in the cells by cellular respiration in our body? Is the role of these molecules essential in the transportation of food in plants? Support your answer.
Ans:
★ ATP is synthesized during cellular respiration, which break down glucose to generate a large amount of usable energy.
★ In plants, ATP is crucial for active transport, providing the necessary energy for moving nutrients, such as the food molecules produced during photosynthesis, against their concentration gradients from the leaves to other parts of the plant.
71. Mention any three strategies by which the food is taken in and used in hetrotrophs with an example for each.
Ans:
★ Some organisms break-down the food material outside the body and then absorb it. Examples are fungi like bread moulds, yeast and mushrooms.
★ Others take in whole material and break it down inside their bodies Example humans and animals
★ Some other organisms derive nutrition from plants or animals without killing them. like cuscuta (amar-bel), ticks, lice, leeches and tapeworms.
IV. Answer the following questions (Three marks questions)
72. Draw a diagram showing the schematic sectional view of the human heart. Label the parts.
Ans:
73. Explain the process of digestion that takes place in the small intestine of a human.
Ans:
★ The small intestine is the place where proteins, carbohydrates and fats in food are completely digested.
★ Enzymes in intestinal juice convert proteins into amino acids, fats into fatty acids, and complex carbohydrates into glucose.
★ Villi in the inner wall of the small intestine absorbs digested food.
74. Explain the process of transport of nutrients in plants.
Ans:
★ The translocation of food substances in plants takes place in the phloem tissue.
★ The translocation of food and other substances takes place in both upward and downward directions with the help of the lateral companion cells of the phloem
★ This action is achieved by Osmotic pressure.
75. The pictures given below represent the hearts of three different animals. Observe them and answer the questions.
Which of these hearts is useful for an animal that needs a lot of energy and why?
Ans:
★ Heart -
★ Oxygenated and deoxygenated blood are transported separately.
★ Provides maximum oxygen to the body.
76. How are the functions of arteries, veins and capillaries related to each other in blood circulation?
Ans:
★ Arteries carry blood from the heart to various organs of the body. Once an artery reaches a tissue, it divides into smaller vessels to bring the blood into contact with each cell.
★ The exchange of substances between the blood and the surrounding cells takes place through the thin walls of very small vessels called capillaries. The capillaries then join together to form veins.
★ Arteries carry blood away from an organ or tissue. Veins collect blood from different organs and bring it back to the heart.
77. How is water transported to the higher parts of a plant? Explain.
Ans:
★ Cells in contact with the soil or in the roots actively absorb ions. This creates a difference in the concentration of ions between the roots and the soil.
★ To overcome this difference, water moves from the soil to the roots. There, the constant movement of water within the xylem of the roots creates a column of water that continually pushes water upward.
★ In transpiration, water molecules evaporating from the stomata of leaves cause absorption, which draws water from the xylem cells of the roots.
78. State the differences between the circulatory systems of fish and humans.
Ans:
79. Explain the stages of 'double circulation' in humans.
Ans:
Stages of blood transport in the heart:
★ Oxygen-rich blood enters the left atrium from the lungs.
★ When the left atrium relaxes and contracts, the left ventricle dilates, and blood is pumped out.
★ When the left ventricle contracts, blood is pumped into the body through the aorta.
★ Deoxygenated blood enters the right atrium through the superior vena cava and the inferior vena cava.
★ When the right atrium contracts, blood is pumped into the right ventricle.
★ When the right ventricle contracts, the blood reaches the lungs to be oxygenated.
80. In plants, state the events that take place in photosynthesis. What are the methods used by plants to eliminate waste products?
Ans:
★ Absorption of solar energy by chlorophyll.
★ Conversion of light energy into chemical energy / decomposition into water, oxygen and hydrogen molecules.
★ Carbon dioxide is converted into starch.
★ Wastes generated in plants such as excess water is removed by evaporation. Oxygen and carbon dioxide gases are released through stomata.
★ Wastes and dead cells in the alders shed leaves/bark.
★ Resins and gums accumulate in old Xylems
★ Some excrete wastes into the soil around them.
81. a) In what form do waste products accumulate in the old xylem of plants?
b) How are the products of photosynthesis transported to all parts of the plant?
Ans:
a) Waste materials accumulate in the form of resins and gums in the old xylem of plants.
b)
★ Transferring a substance like sucrose to the phloem tissue using energy from ATP.
★ Then the convective pressure of the tissue increases, and water enters it. This pressure causes substances to move from the phloem to tissues with lower pressure.
82. Explain the structure and function of nephron.
Ans:
★ Nephrons are the structural and functional units of the kidneys.
★ Nephrons are the blood-purifying units of the kidney, consisting of the glomerulus, Bowman's capsule, and the loops of Henle.
★ These are the kidneys that remove nitrogenous wastes such as urea or uric acid from the blood.
83. Explain the mode of nutrition process in amoeba.
Ans:
★ Amoeba ingests food using temporary finger-like cell surface protrusions.
★ These structures engulf and fuse food particles, forming a food sac
★ In the alimentary canal, complex food substances are broken down into simple food substances, which are then diffused into the cell membrane. The remaining undigested substances move to the cell surface and are excreted.
84. How do the quantity of urine production in humans is controlled?
Ans:
★ The amount of urine excreted is less than the amount of urine produced in Bowman's capsule
★ The amount of urine produced depends on the water content of the body.
★ The more water content in the body, the more urine produced.
85. In two animals P and Q, the small intestine is 85 feet and 15 feet long respectively, in which animal the digestion process is slow and fast? Why? Explain with suitable answer.
Ans:
★ Digestion is slow in animal P. This is because this animal is herbivorous and cellulose needs time to digest in the small intestine.
★ The digestive process is faster in animal Q. Because this animal is a carnivore, meat is easily digested in the small intestine.
86. What is the role of the following enzymes in the human digestive track?
i) Trypsin ii) Amylase iii) Lipase
Ans:
i) Digests protein in food.
ii) Breaks down complex molecules called starch and releases sugar.
iii) Breaks down emulsified unsaturated fats
87. What are the differences between nutrition in autotrophs and nutrition in heterotrophs?
Ans:
88. Draw a schematic diagram showing the breakdown of glucose by various pathways.
Ans:
89. a) State any two methods used by plants to excrete waste products.
b) Which process helps in transporting water to the higher parts of the plant?
Ans:
a)
★ Accumulation of waste in the form of glue and resins in old xylem
★ By shedding leaves
★ By releasing waste into the soil around them
★ Increased water loss through evaporation
★ Oxygen through photosynthesis
★ Carbon dioxide through respiration
b) Evaporation
90. a) How is urine produced in the human body? Explain.
b) State the function of the following digestive juices in the human digestive track:
i) Gastric juice ii) Intestinal juice
Ans:
★ Filtration of blood by a group of blood capillaries in the goblet cells of the nephron.
★ The filtered fluid contains sugars, amino acids, salts, and excess water reabsorbed by the nephron's tubule.
★ The remaining water and salts are excreted in the urine.
b)
i)
★ Hydrochloric acid creates an acidic medium and helps the action of pepsin enzyme.
★ Protein breakdown by pepsin enzyme
ii)
★ Converting proteins into amino acids
★ Converting carbohydrates into glucose
★ Converting fats into fatty acids and glycerol
91. State three ways in which parasite or heterotrophs consume food and utilize. Give 3 examples.
Ans:
★ Some organisms break down food substances outside the body and then absorb them
Ex: Bread mold, yeast
★ Some organisms consume food and break it down within their bodies.
Ex: Humans and higher animals
★ Some organisms obtain nutrition from plants and animals without killing them. E.g. lice, leeches
V. Answer the following questions (4 marks questions)
92. In the first stage of cellular respiration, the glucose molecule is broken down into which molecule in the cytoplasm? Mention the types of respiration and write any two differences between them.
Ans: Pyruvate is broken down into molecules.
Two types: i) Aerobic respiration ii) Abiotic respiration
93. What are the elements required for photosynthesis? State the events that take place in this process. Express this process through a balanced chemical equation.
Ans: The elements required for photosynthesis are:
Carbon dioxide, water, minerals, sunlight, and (leaf) chlorophyll.
Events that occur in photosynthesis
i) Absorption of light energy by chlorophyll.
ii) Light energy is converted into chemical energy
iii) Water molecules are split into hydrogen and oxygen molecules.
iv) Carbon dioxide is reduced to carbohydrates.
94. a) Compare the functions of xylem tissue with those of phloem tissue.
b) Explain the process of gas exchange in plants through stomata.
Ans:
a)
b)
★ Large intercellular spaces in plants allow all cells to be in contact with air, so that carbon dioxide and oxygen can be exchanged by diffusion. That is,
★ These gases move in and out of the cell into the atmosphere/air.
95. a) How does the structure of the human heart help in the transport of oxygenated and deoxygenated Blood? Explain.
b) How is digested food absorbed into the blood in humans? Explain the function of blood in the transport of essential substances.
Ans:
a)
★ The heart has different chambers.
★ Valves between the chambers prevent the backflow of blood.
★ Has a dividing wall called a septum.
★ A structure called a septum creates separate pathways for the transport of oxygenated and deoxygenated blood.
b)
★ Absorbed by finger-shaped structures called villi in the small intestine.
★ Blood plasma - transports food, carbon dioxide, and nitrogenous wastes.
★ RBC - transports oxygen
Blood carries many other substances, such as salts.
96. Name the components of blood and write their functions.
Ans:
★ Plasma: Transport of food, carbon dioxide and nitrogenous wastes
★ Red blood cells: Transport of oxygen
★ White blood cells: protect the body from pathogenic microorganisms
★ Platelets: help blood clotting.
97. a) Briefly explain the role of haemoglobin pigments in our blood.
b) What are the different excretion methods found in plants?
Ans:
a)
★ Hemoglobin pigment gives blood its red color and is highly attracted to oxygen.
★ It dissolves in blood and supplies oxygen to all the cells of the body through blood circulation.
b)
★ Excess water is removed through evaporation.
★ Plant waste products accumulate in the cell sap.
★ Waste products accumulate in the leaves and fall off.
★ Waste materials accumulate in the form of resins and glues in old trees.
★ Plants release some waste into the soil around them.
98. a) Compare the air sacs in the lungs and the nephrons in the kidneys on the basis of structure and function.
b) The muscle cramps occur in the legs of a football player due to continuous practice. Give a suitable reason.
Ans:
a)
b) His legs are deprived of oxygen due to constant exercise and lactic acid builds up.
99. a) What is anaerobic respiration? What are the products produced in this process?
b) What is double circulation? How is this type of blood circulation useful in birds and mammals?
Ans:
a)
★ Respiration in the absence of oxygen is called anaerobic respiration.
★ Alcohol, carbon dioxide and energy
b)
★ To provide the body with pure blood, the blood passes through the heart twice. This is called double circulation.
★ To provide more energy.
★ To maintain a constant temperature in the body.
100. What are the advantages that terrestrial animals have compared to aquatic animals in terms of obtaining oxygen for respiration?
Ans:
★ Aquatic organisms use oxygen dissolved in water.
★ Terrestrial organisms use free oxygen in the environment.
★ The amount of oxygen in the land area is more than the oxygen dissolved in water.
★ Since it is free oxygen, it does not require any further modification in the body
101. How are the lungs designed in humans to increase the area for gas exchange?
Ans:
★ Lungs The trachea branches into bronchioles
★ The bronchioles eventually become balloon-like structures called air sacs.
★ These air sacs provide a surface
★ The walls of the alveoli have an extensive network of blood vessels. Here gas exchange takes place
VI. Answer the following questions (5 marks questions)
102. a) How is glucose converted into energy molecules in aerobic respiration? What is the role of stomata in the process of respiration in plants?
b) What are the different excretion methods found in plants?
Ans:
a)
★ The six-carbon molecule glucose is broken down into three-carbon molecules pyruvate in the Cytoplasm.
★ Pyruvate is broken down in the mitochondria to produce carbon dioxide and water
★ The energy released during respiration is used to synthesize a molecule called ATP.
b) What are the different excretion methods found in plants?
The walls of the air sacs have a network of blood vessels, providing a surface for gas exchange.
No comments:
Post a Comment