Chapter 6 Life Processes Class 10 Science Extra Questions
Chapter 6 Life Processes Extra Questions and Answer
Chapter Name | Life Processes Extra Questions |
Class | CBSE Class 10 |
Textbook Name | Life Processes Class 10 |
Related Readings |
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Very Short Answer Type
Question 1. What will happen to a plant if its xylem is removed? [CBSE 2009]
Answer
Xylem helps in the transport of water and minerals to the various parts of the plant. If xylem is removed it would ultimately lead to the death of the plant.
Question 2. Name the green dot like structures in some cells observed by a student when a leaf peel was viewed under a microscope. What is the green colour due to? [CBSE 2010]
Answer
The green dots like structures seen are the chloroplasts. The green colour is due to the pigment called chlorophyll.
Question 3. Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. [CBSE 2010]
Answer
Simple diffusion is not sufficient for the exchange of gases in multicellular organisms as all their cells are not in direct contact with the environment. So, they require special organs for exchange of gases between their body and their environment.
Question 4. What process in plants is known as transpiration? [CBSE 2008]
Answer
The loss of water in the form of vapour from the aerial parts of the plant is known as transpiration.
Question 5. What is osmoregulation? [CBSE 2006]
Answer
The maintenance of optimum concentration of water and salts (electrolytes) in the body fluids is called as osmoregulation.
Question 6. Why is carbon dioxide mostly transported in dissolved form?
Answer
Carbon dioxide is mostly transported in the dissolved form as it is more soluble in water.
Question 7. When we breathe out, why does the air passage not collapse? [CBSE 2014]
Answer
Rings of cartilage present on trachea prevent it from collapsing during the passage of air.
Question 8. Herbivores have longer small intestine while carnivores have shorter small intestine. Give reason. [CBSE 2014]
Answer
Herbivores have a longer small intestine compared to the carnivores to allow time for the cellulose present in the grass to get digested.
Question 9. Mention the respiratory unit of lungs and excretory unit of kidneys. [CBSE 2014]
Answer
The respiratory unit of lungs are alveoli and excretory unit of kidneys are nephrons.
Question 10. Some organisms derive nutrition from plants or animals without killing them. What are these organisms called? Write one example. [CBSE 2014]
Answer
They are called parasites, e.g. Cuscuta and tapeworm are the parasites of plants and animals respectively.
Question 11. What are the major constituents of urine? [CBSE 2008]
Answer
Urine is an aqueous solution of water, urea, chloride, sodium, potassium, creatinine and other dissolved ions, inorganic and organic compounds (proteins, hormones, and metabolites).
Question 12. Where does the urine produced by the kidneys get stored? [CBSE 2006]
Answer
Urinary bladder.
Question 13. How does transpiration help in upward transport of substances? [CBSE 2008]
Answer
Transpiration creates a suction pressure which pulls up water along with the minerals through the xylem.
Question 14. When the right atrium contract, blood flows from it to which part of the heart? [CBSE 2007]
Answer
Right ventricle.
Question 15. State the functions of the following:
(i) Red Blood Cells (RBC)
(ii) WBC [CBSE 2011, 2012]
Answer
- Function of RBC: To carry oxygen to various parts of the body.
- Function of WBC: To protect the body against both infectious diseases and foreign invaders.
Question 16. Write the functions of the two upper chambers of the human heart. [CBSE 2011]
Answer
The right atrium receives deoxygenated blood from various parts of the body through the vena cava.
The left atrium receives the oxygenated blood from the lungs through the pulmonary artery.
Question 17. Leakage of blood from vessels reduces the efficiency of pumping system. How is the leakage prevented? [CBSE 2010, 2011]
Answer
Leakage is prevented by the blood platelets present in the blood which help in clotting the blood at the site of injury.
Question 18. Which mechanism plays an important role in transportation of water in plants
(i) During daytime
(ii) At night? [CBSE 2011, 2012]
Answer
(i) During daytime – Transpiration;
(ii) At Night – Root pressure.
Question 19. Why are valves present in heart and the veins? [CBSE 2010,2011]
Answer
Valves present in the heart does not allow the blood to flow backwards when the atria or ventricles contracts. Valves are present in the veins to prevent the back flow of blood in the veins as it travels at very slow rate in the veins.
Short Answer Type
Question 1. How are the fats digested in our bodies? Where does this process take place? [CBSE 2011]
Answer
Bile juice produced by the liver breaks down the large fat globules into smaller globules by the process of emulsification. These small globules are then digested by the fat digesting enzymes. This process takes place in the small intestine.
Question 2. State the function of the epiglottis. [CBSE 2004]
Answer
Epiglottis covers the opening of the wind pipe (the glottis) and prevents the entry of food into the wind pipe during swallowing.
Question 3. The breathing cycle is rhythmic, whereas exchange of gases is a continuous process. Comment upon this statement.
Answer
Some volume of air called as residual volume is left behind in the lungs even after forceful breathing out of air. This helps to provide sufficient time for oxygen to be absorbed and for carbon dioxide to be released. Even in the absence of continuous breathing, the exchange of these gases is continuous.
Hence, breathing cycle is rhythmic, whereas exchange of gases is a continuous process.
Question 4. What are the end products formed during fermentation in yeast? Under what condition a similar process takes place in our body that lead to muscle cramps? [CBSE 2010]
Answer
The end products formed during fermentation in yeast are ethanol and carbon dioxide. A similar process occurs in the muscles and produces lactic acid during anaerobic respiration in the muscles.
Accumulation of lactic acid in the muscle cells lead to muscular cramps.
Question 5. Give Reasons:
(a) Rings of cartilage are present in the trachea.
(b) Lungs always contain a residual volume of air. [CBSE 2013]
Answer
(a) The walls of trachea have rings of cartilage on them which prevent it from collapsing.
(b) The volume of air left behind in the lungs even after forceful breathing out of air is called as residual volume. This helps to provide sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
Question 6. State in brief the role of lungs in the exchange of gases. [CBSE 2012]
Answer
Lungs have alveoli which provide a larger surface for exchange of gases and are richly supplied with blood vessels to enable faster exchange. So, lungs help in providing oxygen to various tissues of the body and removal of carbon dioxide from the body.
Question 7. What is the basic unit of kidney called? Why is it composed of very thin blood capillaries? [CBSE 2015]
Answer
The basic unit of kidney is called nephron. It is composed of a cluster of very thin blood capillaries as they help in filtration of blood and remove the nitrogenous wastes from the body in the form of urine.
Question 8. How does the plant get rid of excretory products? [CBSE 2009]
Answer
Excess oxygen and carbon dioxide removed through stomata.
Plant waste products are also removed by:
- Storage in cellular vacuoles
- Storage in leaves that fall off
- Storing as resins and gums in old xylem
- By excreting into the soil around them.
Question 9. Tabulate two differences between renal artery and renal vein. [CBSE 2009]
Answer
Renal Artery
- Blood in renal artery contains glucose, oxygen and cellular waste products.
- It takes blood towards the kidney.
Renal Vein:
- Blood in renal vein is filtered, and is free from cellular waste and any other impurities.
- It takes blood away from the kidney towards the heart.
Question 10. (a) What is the main toxic waste that kidney filters from the blood?
(b) Name any two substances which are selectively reabsorbed from the tubules of a nephron. [CBSE 2010, 2012]
Answer
(a) Urea is the main excretory product removed by the kidneys of human beings.
(b) The substances selectively reabsorbed by the kidneys are water, glucose, electrolytes, etc.
Question 11. What is excretion? How do unicellular organisms remove their wastes? [CBSE 2012]
Answer
Removal of metabolic wastes from the body is called as excretion. Many unicellular organisms remove metabolic wastes from the body surface into the surrounding water by simple diffusion.
Question 12. Write a function of (a) blood vessels (b) blood platelets. [CBSE 2008]
Answer
(a) Blood vessels help in carrying blood to various parts of the body.
(b) Blood platelets help in the clotting of blood at the point of injury to prevent non-stop bleeding.
Question 13. How are water and minerals absorbed by the plant? [CBSE 2010]
Answer
The water and minerals in the soil are absorbed by plants with the help of root hairs present on their roots. Root hairs provide a larger surface area for absorption.
Question 14. What are capillaries? Sate the function performed by them. [CBSE 2012]
Answer
The capillaries are one-cell thick, small blood vessels which help in the exchange of materials between the blood and the surrounding tissues.
Question 15. Mention the two main components of the transport system in plants. State one function of each one of these components. [CBSE 2010, 2011]
Answer
The two main components of the transport system in the plants are xylem and phloem. Xylem helps to transport water and minerals to various parts of the plant. Phloem helps to carry food from leaves to the various parts of the plant.
Question 16. During one cycle how many times does blood go to the heart of fish and why? [CBSE 2010]
Answer
The blood passes only once through the heart in one cycle in fishes because the two-chambered heart of the fishes pump the blood to gills for oxygenation. The blood from gills is then directly passed to the various parts of the body in the fishes.
Question 17. What would be the consequences of deficiency of haemoglobin in our bodies? [CBSE 2012]
Answer
Haemoglobin helps in transport of oxygen to the body parts. Deficiency of haemoglobin will affect transport of oxygen and the person will suffer from improper metabolism, weakness, fatigue and pain.
Question 18. Name the following:
(а) The process in plants that links light energy with chemical energy.
(b) Organisms that can prepare their own food.
(c) The cell organelle where photosynthesis occurs.
(d) Cells that surround a stomatal pore.
(e) Organisms that cannot prepare their own food.
(f) An enzyme secreted from gastric glands in stomach that acts on proteins. [NCERT Exemplar]
Answer
(a) Photosynthesis
(b) Autotrophs
(c) Chloroplast
(d) Guard cells
(e) Heterotrophs
(f) Pepsin
Question 19. “All plants give out oxygen during the day and carbon dioxide during night”. Do you agree with this statement? Give reason. [NCERT Exemplar]
Answer
The rate of photosynthesis is higher than the rate of respiration during the daytime, so the net result is the evolution of oxygen. In the absence of photosynthesis at night, only respiration occurs in the plants so carbon dioxide is released at night.
Question 20. How do the guard cells regulate opening and closing of stomatal pores? [NCERT Exemplar]
Answer
The entry of water into the guard cells of the stomata causes an increase in turgor pressure in the guard cells which leads to opening of the stomata. The loss of water from the guard cells results in their shrinking and closes the stomata.
Question 21. 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. [NCERT Exemplar]
Answer
Plant kept in continuous light will perform photosynthesis and release oxygen for its respiration. Hence, it will live longer than the plant kept in the dark.
Question 22. 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. [NCERT Exemplar]
Answer
During the day time the plants take in carbon dioxide and release oxygen as a by product of photosynthesis. Release of carbon dioxide and taking in air during the daytime means that either the rate of photosynthesis is too low or its not occurring at all.
Question 23. Why do fishes die when taken out of water? [NCERT Exemplar]
Answer
Fishes take water from mouth and send it to the gills which are richly supplied with blood capillaries for absorbing the oxygen dissolved in water. But the fishes cannot absorb gaseous oxygen, so they die soon after they are taken out of water.
Question 24. Is ‘nutrition’ a necessity for an organism? Discuss. [NCERT Exemplar]
Answer
Nutrition (food) is a necessity for an organism as
- It provides energy for the various metabolic processes in the body.
- It is essential for the growth and repair of various cells and tissues.
- It helps to provide resistance against various diseases.
Question 25. What would happen if green plants disappear from the Earth? [NCERT Exemplar]
Answer
The green plants are the source of energy for the entire organisms on the Earth. Herbivores depend directly on the plants while the carnivores and omnivores depend either directly or indirectly on plants. So, all the organisms will die due to starvation if all the green plants disappear from the Earth.
Question 26. Leaves of a healthy potted plant were coated with vaseline. Will this plant remain healthy for long? Give reasons for your answer. [NCERT Exemplar]
Answer
This plant will not remain healthy for a long time because the stomata will get blocked, so plant
- Will not get carbon dioxide for photosynthesis.
- Will not get oxygen for respiration.
- Will not be able to do transpiration which will in turn affect the upward transport of water and minerals.
Long Answer Type
Question 1. (a) Explain why the rate of photosynthesis is low both at lower and higher temperatures.
(b) Is green light most or least useful in photosynthesis and why? [CBSE 2005]
Answer
(a) The reactions occurring during the process of photosynthesis is under the control of enzymes, which work under an optimum range of temperature only. The very high temperatures as well as very low temperatures decrease the activity of the enzymes. So, the rate of photosynthesis is low both at lower and higher temperatures.
(b) Chlorophyll does not absorb the green light, so the green light is least useful in photosynthesis.
Question 2. Draw a well labelled diagram of stomata. List two functions of stomata. [CBSE 2011]
Answer
The function of stomata are:
- Help in the exchange of gases like carbon dioxide and oxygen from the leaves of the plants.
- Help in the transport of water, minerals and food materials in plants by transpiration.
- Transpiration occurring through stomata on leaves helps in cooling of leaf surface.
Question 3. Explain how the products of photosynthesis and other substances are translocated in plants? [CBSE 2015]
Answer
Translocation is the transport of soluble products of photosynthesis through phloem. Sucrose is transferred into sieve tubes of phloem via the companion cells using energy from ATP. This increases the osmotic pressure inside the sieve tubes which causes movement of water into the sieve tubes from the adjacent xylem. This pressure helps in translocation of material in the phloem to tissues which have less pressure.
Question 4. Write three events which occur during the process of photosynthesis. [CBSE 2015]
Answer
The three events which occur during photosynthesis are:
- Absorption of light energy of chlorophyll.
- Conversion of light energy to chemical energy + splitting of water molecules into hydrogen and oxygen.
- Reduction of carbon dioxide to carbohydrates.
Question 5. Explain why the transportation of materials is necessary in animals? [CBSE 2014]
Answer
The transportation system is necessary to transport the various nutrients and gases to and from the various parts of the body. It also helps in removing the wastes from the body of the organisms. The various life processes are maintained and carried out due to an efficient transport system in animals.
Question 6. Plants absorb water from the soil. Explain how does the water reach the tree top? [CBSE 2014]
Answer
There are two ways for the transport of water in plants:
(а) By root pressure: The cells of root in contact with soil actively take up ions which creates a difference in ion concentration between the root and the soil. Water moves into the root from the soil to eliminate this difference, creating a column of water that is steadily pushed upwards.
(b) By transpiration pull: Loss of water from stomata by transpiration gets replaced by the xylem vessels in the leaf which creates a suction to pull water from the xylem cells of the roots. This strategy is used during day time and helps to transport water to the highest points of the plant body.
Question 7. State the function of the following in the alimentary canal.
(a) Liver
(b) Gallbladder
(c) Villi [CBSE 2014]
Answer
(a) Liver: Helps in detoxification of harmful chemicals. Produces bile juice which helps in digestion of fats.
(b) Gall bladder: Helps in the storage of bile juice released from the liver.
(c) Villi: Helps to increase the surface area of the small intestine and aid in absorption of the digested nutrients.
Question 8. (a) How does exchange of respiratory gases - oxygen and carbon dioxide take place between tissues and blood in human beings?
(b) Name the respiratory pigment in humans. Where is it found? [CBSE 2014]
Answer
(a) The arteries have oxygenated blood having oxygen at higher pressure to that present in the tissues. Carbon dioxide is present at a higher pressure inside the tissues. The oxygen is thus exchanged at the tissue surface with carbon dioxide in order to supply oxygen to the tissues of the body.
(b) Haemoglobin is the respiratory pigment in humans which is present in the red blood cells.