Class 10 Life Processes Competency-Based Questions
1 Mark Questions
1. Two statements are given – one labelled Assertion (A) and the other labelled Reason (R). Read the statements carefully and choose the option that correctly describes statements A and R.
- Assertion (A): Warm-blooded animals have their left and right side of the heart separated for a more efficient supply of oxygen to the body.
- Reason (R): Warm-blooded animals need high energy to maintain their body temperatures.
- Both A and R are true, and R is the correct explanation for A.
- Both A and R are true, but R is not the correct explanation for A.
- A is true, but R is false.
- A is false, but R is true.
Ans: a. Both A and R are true, and R is the correct explanation for A.
2. Haemoglobin and Chlorophyll have similar structures.
- A molecule of haemoglobin is composed of the atoms of four elements- carbon, hydrogen, oxygen and nitrogen, all four organised around iron.
- A chlorophyll is composed of the same elements, which are organised around magnesium.
Considering the above information, which element of haemoglobin is MOST LIKELY responsible for the red colour of our blood?
- hydrogen
- nitrogen
- carbon
- iron
Ans: d. Iron
3. Many processes happen in the bodies of living organisms. Those processes which involve the building up of complex molecules from simpler ones are called anabolism. Those which involve the breakdown of complex molecules into simpler ones are called catabolism. Which of the following life processes can be considered as an example of anabolism?
- digestion
- respiration
- transpiration
- Photosynthesis
Ans: d. Photosynthesis
4. Given below is a diagram of a nephron.
Which row of the following table correctly shows where filtration and selective reabsorption occur?
| Filtration | Selective reabsorption | |
| 1 | P | Q |
| 2 | Q | S |
| 3 | Q | R |
| 4 | P | R |
Ans: Option 4
5. Which row in the table below shows the correct products of anaerobic respiration in humans and in yeast?
| Humans | Humans | Yeast | Yeast | |
| Lactic acid | Carbon dioxide | Lactic acid | Carbon dioxide | |
| 1 | No | Yes | No | No |
| 2 | Yes | No | No | Yes |
| 3 | No | Yes | Yes | No |
| 4 | Yes | Yes | Yes | No |
Ans: Option 2
6. Read the following two statements and answer the question.
- Gastroparesis is a disease in which the muscles of the stomach become paralysed and cannot contract or relax.
- Foods high in fat can delay the process of digestion and the emptying of the stomach.
Which of the following foods would be advised for a patient suffering from gastroparesis?
- soups and juices only
- soups and chicken salads only
- fried chicken and fried rice
- ice cream and milk only
Ans: a. soups and juices only
7. Which row of the table given below correctly gives the movement of gases across blood and cells?
| Oxygen | Carbon dioxide | |||||
| From | To | Process | From | To | Process | |
| 1 | RBC | Cells | Diffusion | Cells | RBC | Osmosis |
| 2 | RBC | Cells | Osmosis | Cells | Plasma | Osmosis |
| 3 | RBC | Cells | Osmosis | Cells | RBC | Diffusion |
| 4 | RBC | Cells | Diffusion | Cells | Plasma | Diffusion |
Ans: Option 4
8. Read the following statements.
- X: amount of carbon dioxide produced per molecule of glucose during aerobic respiration
- Y: amount of carbon dioxide produced per molecule of glucose during fermentation by yeast
Which of the following is TRUE about X and Y?
- X is more than Y.
- X is less than Y.
- X is equal to Y.
- (Cannot be determined.)
Ans: a. X is more than Y
Multiple Choice Question
Answer the questions based on the following information.
William Harvey (1578–1657) was one of the early biologists who studied the bodies of humans and animals. He even dissected the bodies and did experiments with the heart and blood vessels. He concluded from his experiments that the blood leaves the heart through the arteries and returns via the veins. However, he could not explain how blood left the arteries to enter the veins. He said there must be some structure between arteries and veins, but he could not find them. Marcello Malpighi (1628–1694) later discovered these structures while studying a dead frog’s lungs under a microscope.
9. Which of the following structures did Malphigi find in the frog?
- Cells
- Capillaries
- Heart chambers
- Small air sacs in lungs
Ans: b. Capillaries
10. What is the MOST LIKELY reason why Harvey could NOT find these structures?
- These structures are not found in humans.
- These structures are found only in the lungs.
- These structures become visible only in dead animals.
- These structures were too small to be seen by the naked eye.
Ans: d. These structures were too small to be seen by the naked eye.
11. Which of the following statements about arteries and veins is TRUE?
- Arteries have thicker walls than veins.
- Veins have thicker walls than arteries.
- All arteries carry only oxygenated blood.
- All veins carry only deoxygenated blood.
Ans: a. Arteries have thicker walls than veins.
12. Which two chambers of the human heart have arteries connected to them?
- left atrium and left ventricle
- right atrium and right ventricle
- left atrium and right atrium
- left ventricle and right ventricle
Ans: d.left ventricle and right ventricle
2 Marks Questions
13. A major portion of the carbohydrates produced by plants is stored in different parts of the plant (storage organs). Explain the mechanism by which this stored food is made available when different organs need it for growth.
Ans:
- Sugar from the storage organ is moved to the phloem using ATP/energy.
- This increases the osmotic pressure of phloem.
- This results in the intake of water into the phloem.
- Increased pressure inside the phloem cells causes sugar to move to cells with lower pressure, allowing it to reach other organs.
14. In human beings, hormonal action is largely controlled by a mechanism where the secretion of one hormone is regulated by the action of another. An example of blood glucose level control is shown in the diagram below.
(a) What is the mechanism of hormone action known as?
(b) Which is the sensor X that helps in detecting blood glucose level?
(c) What would happen if such a mechanism is absent in humans?
Ans:
- (a) feedback mechanism
- (b) beta cells OR cells of the pancreas
- (c) Balance of life processes would be disturbed in the human body.
15. When some particles (like sand or dust) fall into our eyes, our eyes start to water on their own, and we blink to get the particles out of our eyes. This is a type of reaction to a stimulus that the human body shows.
- (a) Is the above-mentioned reaction involuntary or voluntary?
- (b) What is the specific name given to the pathway that brings about this immediate reaction to a stimulus?
- (c) What are the names given to:
- (i) the organ that responds to a stimulus
- (ii) the part of the brain that receives sensory impulses
Ans:
- (a) involuntary
- (b) reflex arc
- (c)
- (i) effector
- (i) forebrain
16. The image below shows the cross-section of a blood vessel in a human arm.
(a) What is the type of blood vessel shown in the image?
(b) Which direction will the blood flow in such a blood vessel?
Ans:
- (a) vein
- (b) from P to Q
17. There are various muscles present in the human digestive system known as sphincters. Two examples of those are given below:
1. pyloric sphincter – at the junction of stomach and small intestine
2. anal sphincter – at the anus
Give ONE most likely consequence of malfunctioning of each of these sphincters.
Ans:
- Pyloric sphincter: food getting into the small intestine too fast, causing poor absorption / poor digestion
- Anal sphincter: involuntary release of faeces from the body
18. Arthropods and molluscs have a copper-containing respiratory pigment called hemocyanin, while human beings have iron-containing hemoglobin.
(a) How do respiratory pigments help in the process of respiration?
(b) Why do multicellular animals need respiratory pigments?
Ans:
- (a) Respiratory pigments combine with oxygen and help in the transport of oxygen throughout the body.
(b) When the body size of animals is large, diffusion pressure alone cannot take care of oxygen delivery to all parts of the body. Hence, respiratory pigments take up oxygen from the air in the lungs and carry it to tissues that are deficient in oxygen.
3 Marks Questions
19. Human beings exhibit ‘double circulation’ during which blood is passed through the lungs and heart.
- (a) State the route of the first and the second circulation through the chambers of the heart and explain the usefulness of such circulation in humans.
- (b) Name the blood vessels that:
- (i) carry oxygenated blood from the lungs to the heart
- (ii) carry deoxygenated blood from the heart to the lungs
Ans: (a)
- During the first circulation, oxygenated blood from the lungs comes to the left atrium to the left ventricle, to pass to the body
- During the second circulation, deoxygenated blood from the body comes to the right atrium and then right ventricle to pass for oxygenation to the lungs again.
- allows for the separation of oxygenated and deoxygenated blood in the body
(b)
- (i) pulmonary vein
- (ii) pulmonary artery
20. Terrestrial animals use lungs to breathe while aquatic animals like fishes use gills to absorb dissolved oxygen in water. Frogs are organisms that can survive both in water and on land.
(a) How does a frog acquire oxygen while it is underwater?
(b) Are lungs of terrestrial animals and gills of fishes analogous organs? Explain why or why not.
(c) Why do aquatic animals have a higher breathing rate than terrestrial animals?
Ans:
- (a) A frog’s skin is thin and permeable to oxygen and water. It takes up the dissolved oxygen from the water through the process of diffusion.
- (b) Yes, they are analogous organs. Because they have different structures but similar functions.
- (c) The amount of dissolved oxygen in water is lower as compared to oxygen present in the air. Hence aquatic animals have to breathe faster.
21. We often hear people complain about ‘acidity’ in the stomach.
(a) Overproduction of what substance is most likely the reason for the complaint?
(b) Why is the production of this substance necessary?
(c) How does the stomach prevent itself from the harmful effects of overproduction of the substance?
Ans:
- (a) hydrochloric acid
- (b) It creates an acidic medium for the functioning of the enzyme pepsin.
- (c) The stomach also produces mucus that coats the lining to prevent damage by hydrochloric acid.
22. The developing human embryo gets nutrition from the mother through a special tissue called placenta.
(a) Mention TWO structural designs of the placenta that help the embryo to get nutrition.
(b) Is the placental tissue designed for one-way transport? Justify your answer.
Ans:
(a)
- It has villi on the embryo side.
- It has blood spaces on the mother’s side.
(b) No, the waste generated by the developing embryo is transferred out through the placental tissue.
23. Given below is an image of an experiment conducted by a student to understand the process of respiration. He blows into a clear solution present in the test tube and sees that it turns cloudy.
(a) What is the most likely substance present in the test tube?
(b) What could be the aim of his experiment?
(c) What kind of respiration is shown in the experiment? Justify your answer.
Ans:
(a) lime water / dilute aqueous solution of calcium hydroxide/ Ca(OH)2
(b) To prove that carbon dioxide is released during respiration.
(c) Aerobic respiration
- CO2 is a product of either aerobic respiration or fermentation
- Fermentation does not take place in human cells.
4 Marks Questions
24. Not all plants carry out photosynthesis by the same mechanism. In most plants, photosynthesis depends directly on the gaseous carbon dioxide that diffuses into the leaf through the stomata.
However, some plants – such as pineapple – have the ability to store carbon dioxide in the vacuoles of the leaf cells as part of a complex carbon compound. This complex compound is transported to the chloroplasts and releases carbon dioxide when required, for photosynthesis to occur.
This special photosynthesis mechanism is believed to have evolved as an adaptation to conserve water for survival in dry conditions.
- (a) Which process in the plants does this photosynthesis mechanism minimise to help the plant survive in dry conditions?
- (b) How is the ability to store carbon dioxide as a complex compound likely to help minimise the process referred to in (a)?
- (c) When are such plants likely to take in carbon dioxide from the environment?
Ans:
- (a) transpiration
- (b) 1 mark for each of the following points:
- Since stored carbon dioxide can be utilised, stomata do not need to be open for photosynthesis to occur during the day.
- Keeping the stomata closed during the day helps to minimise water loss due to transpiration.
- (c) during the night
25. Anita conducted an experiment to examine photosynthesis in aquatic plants kept in a tank by measuring dissolved oxygen. She plotted her results in the following graph X:
She repeated the experiment while covering the tank with an opaque black cloth. She
plotted the results in the following graph Y:
(a) What could be the aim of her experiment?
(b) Apart from photosynthesis, what other cellular process can be observed by the experiment?
(c) Why does the oxygen level rise in graph X?
(d) Explain the downward slope of the graph Y.
Ans:
- (a) to show that light is necessary for photosynthesis
- (b) respiration
- (c) In the presence of light, the plants performed photosynthesis, which released oxygen at a higher rate than the rate of oxygen utilisation by respiration. Hence, the oxygen levels rise.
- (d) The downward slope depicts that dissolved oxygen is used up by the plant for respiration, but no new oxygen is produced as the plant does not perform photosynthesis in the absence of light.
26. A Weddell seal, a deep-sea diving mammal, has special adaptations that enable it to respire for long periods underwater without inhaling air. Three such adaptations are given below.
P) When diving, the blood flow to all parts of the seal’s body is reduced by 80-95%, except for a closed circuit between the lungs, heart, and brain.
Q) 70% of the oxygen in the seal’s body is stored in the blood (in haemoglobin), as compared to just 51% in humans.
R) 25% of the oxygen in the seal’s body is stored in the muscles (in myoglobin), as compared to just 13% in humans.
In 1980, a group of scientists carried out an experiment to understand how a Weddell seal respires under water during dives of different durations. After each dive completed by the seal, they measured the concentration of lactic acid in the seal’s blood. The graph below represents the data obtained by the scientists.
- (a) Based on the graph, what can be inferred about the CHANGE in the respiration happening in the seal’s body after 20 minutes under water? Justify your answer.
- (b) Adaptation R helps the seal the most to produce energy for SWIMMING during the first 20 minutes of a dive. Explain why adaptations P and Q do not help as much.
Ans: (a) Respiration is mostly aerobic in the first 20 minutes, and mostly anaerobic after 3 the first 20 minutes.
Justification:
- Lactic acid is a product of anaerobic respiration.
- The sharp rise in lactic acid concentration after 20 minutes indicates anaerobic respiration is happening after 20 minutes.
(b)
- The muscles produce most of the energy needed for swimming.
- Since most of the blood does not reach the muscles during a dive, the oxygen stored in the blood is not as useful for swimming as the oxygen stored in the muscles.
5 Marks Questions
Free Response Question/ Subjective Question
27. Aerobic respiration requires intake of oxygen to break down food to release energy.
(a) Name the structures through which gaseous exchange takes place in plants and human beings.
(b) Name the structure that controls the size of the chest cavity in humans to facilitate the exchange of gases.
(c) What is the process by which gas exchange occurs in plants?
(d) Why is the process named in (c) not sufficient to carry oxygen throughout the human body? How is this complemented in humans to ensure that oxygen is carried to all parts of the body?
(e) Reactions in living systems can absorb heat or release heat. State whether the heat energy is absorbed/ released during digestion. Also, write the scientific term to denote the same.
Ans: (a)
- Plants: stomata/guard cells
- Human beings: alveoli/ lungs
(b) diaphragm
(c) diffusion
(d)
- Because diffusion is a slow process, and human beings have complex tissues that might not allow diffusion to happen effectively and easily
- Carried by the blood/haemoglobin in the blood
(e)
- Use up heat
- Endothermic
