LIFE PROCESSES
VERY SHORT ANSWER TYPE QUESTION [1 MARK]
1. What will happen to a plant if its xylem is removed?
Answer. Xylem in plant transports water and dissolved mineral nutrients from the roots to all
parts of the vascular plant. So, if xylem is removed from the plant, the water and mineral supply
to the plant will stop and therefore, the plant will die.
2. Where does digestion of fat take place in our body?
Answer. Digestion of fat takes place in the small intestine of our body.
3. Name one accessory pigment and one essential pigment in photosynthetic plants.
Answer. Accessory pigment – Carotene/Xanthophyll
Essential pigment – Chlorophyll
4. What is the mode of nutrition in human beings?
Answer. Holozoic nutrition.
5. Mention the raw materials required for photosynthesis.
Answer. The following raw materials are required for photosynthesis:
(i) Carbon Dioxide: Plants get CO2 from atmosphere through stomata.
(ii)Water: Plants absorb water from soil through roots and transport to leaves.
(iii) Sunlight: Sunlight, which is absorbed by the chlorophyll and other green parts of the plant.
6. What would be the consequences of deficiency of hemoglobin in your body?
Answer.The deficiency of hemoglobin in our body is called anemia. In anemia, the blood is
unable to carry the sufficient amount of oxygen required by the body. So, respiration would be
less and less energy will be available to the body. The hemoglobin deficient person will feel
weak, pale, lethargic and will be unable to perform heavy physical work.
7. Name the green dot like structures in some cells observed by a student when a leaf peel was
viewed under a microscope. What is this green colour due to?
Answer. The green dot-like structures in some cells observed by a student when a leaf peel is
viewed under a microscope are chloroplasts. The green colour is due to the presence of green
pigment, chlorophyll.
8. State any one difference between autotrophic and heterotrophic modes of nutrition.
Answer. In autotrophic nutrition, organisms obtain their food from inorganic substances. In
heterotrophic nutrition, organisms derive their food from organic substances.
9. Give one reason why multicellular organisms require special organs for exchange of gases
between their body and their environment. :
Answer. In unicellular organisms the entire body of the organism is in contact with the
environment hence exchange of materials can take place but, in multicellular organisms the entire
body of the organism is not in contact with the environment and hence simple diffusion is not
helpful.
10. Name the process in plants where water is lost as water vapour. :
Answer. Transpiration is the process when plants loose water as vapour.
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,11. What is‘translocation’in plants?
Answer. Translocation is the movement of soluble materials, products of photosynthesis from
leaves to other tissues throughout the plant.
12. State the basic difference between the process of respiration and photosynthesis.
Answer. Respiration uses O2 and releases CO2 but in photosynthesis, CO2 is used and O2 is
released.
13. Name the intermediate and the end products of glucose breakdown in aerobic respiration.
Answer.
14. Mention two structural features of small intestine which add to the absorptive capacity.
Answer. Two structural features of small intestine are:
(i) Villi is present to increase the absorptive surface area.
(ii) Lacteals in the villi receive the products of fat digestion.
15. In the experiment “Light is essential for photosynthesis”, why does the uncovered part of
the leaf turn blue-black after putting iodine solution?
Answer. Starch is produced in the uncovered part of the leaf because it is exposed to sunlight
allowing it to photosynthesize, which turns blue-black in presence of iodine solution.
16. Name the component of blood that helps in the formation of blood clot in the event of a cut.
Answer. Platelets help in clotting of blood in the event of a cut.
17. Mention how organisms like bread moulds and mushrooms obtain their food.
Answer. Organisms like bread moulds and mushrooms breakdown the food materials outside the
body and then absorb the nutrients of the bread.
18. What advantage over an aquatic organism does a terrestrial organism have with regard to
obtaining oxygen for respiration?
Answer. The amount of oxygen dissolved in water is very low, as compared to amount of oxygen
in air. Thus, terrestrial organism has to make less efforts to obtain oxygen than an aquatic
organism to obtain oxygen for respiration.
19. Name the two ways in which glucose is oxidised to provide energy in various organisms.
Answer. The two ways in which glucose is oxidised to provide energy in various organisms are
aerobic respiration pathway which uses oxygen to break-down glucose completely into carbon
dioxide and water and some use other pathways that do not involve oxygen which is called
anaerobic respiration pathway.
20. Specify two conditions in which photo-respiration may take place in green plants.
Answer. Two conditions in which photorespiration may take place in green plants are: (i) High
concentration of oxygen and (ii) High temperature
SHORT ANSWER TYPE QUESTIONS[I] [2 MARKS]
21. What are the final products after digestion of carbohydrates and proteins?
Answer. The final product produced after digestion of carbohydrates is glucose and of proteins is
amino acids.
22. What is saliva? State its role in the digestion of food.
Answer. Saliva is a watery fluid secreted by the salivary glands in the mouth. The digestive
Page - 50 -
, functions of saliva include moistening food, and helping to create a food bolus, so it can be
swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into
maltose and dextrin.
23. Explain the process of nutrition in Amoeba.
Answer. The mode of nutrition in Amoeba is holozoic. It feeds on unicellular plant or animal.
The various steps of nutrition are ingestion, digestion, assimilation and egestion. When Amoeba
comes in contact with food particles, it sends out pseudopodia, which engulfs 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 food vacuole. The food vacuole serves as a
temporary stomach secreting digestive juice, this step is known as digestion. The digested food
gets absorbed and diffuses into the cytoplasm and then assimilated. Egestion of undigested food
takes place at any point on the surface of the body.
24. State two differences between arteries and veins.
Answer. Arteries: Arteries carry oxygenated blood, away from the heart except pulmonary
artery. These are thick-walled, highly muscular except arteries of cranium and vertebral column.
Valves are absent. Blood in arteries moves with pressure.
Veins: Veins carry deoxygenated blood, towards the heart except pulmonary veins. These are
thin-walled. Valves are present which provide unidirectional flow of blood.
Blood in veins moves under very low pressure.
25. How are the alveoli designed to maximise the exchange of gases?
Answer.Alveoli are small pouches or sacs like structure. They are surrounded by blood
capillaries. Thus a large amount of air is brought in contact with the air in the lungs. More than
millions of alveoli are present in the lungs. The presence of millions of alveoli in the lungs
provides a very large surface area for the exchange of gases. The availability of large surface area
maximises the exchange of gases.
26. Explain the mechanism of gaseous exchange between tissues and blood.
Answer. 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
lungs has high concentration of oxygen and 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.
27. Describe the mechanism of blood clotting.
Answer. Blood Clotting: It is the mechanism that prevents the loss of blood at the site of an injury
or wound by forming a ‘blood clot’. The blood has platelet cells which circulate around the body
and plug these leaks by helping to clot the blood at these points of injury to prevent it from
excessive bleeding.
28. Why are white blood corpuscles called ‘soldiers’ of the body?
Answer. White blood corpuscles can fight with the disease germs present in the body carried by
blood and help to maintain a healthy body. So, they are called as ‘soldiers’ of the body.
29. Which part of the human heart is considered as pace-maker? Why is it so called?
Answer. Sino-atrial node of the human heart is considered as pacemaker. Sino-atrial node is also
called as pacemaker because it determines the rate of heartbeat by determining the rate of
discharge of cardiac impulse.
Page - 51 -
VERY SHORT ANSWER TYPE QUESTION [1 MARK]
1. What will happen to a plant if its xylem is removed?
Answer. Xylem in plant transports water and dissolved mineral nutrients from the roots to all
parts of the vascular plant. So, if xylem is removed from the plant, the water and mineral supply
to the plant will stop and therefore, the plant will die.
2. Where does digestion of fat take place in our body?
Answer. Digestion of fat takes place in the small intestine of our body.
3. Name one accessory pigment and one essential pigment in photosynthetic plants.
Answer. Accessory pigment – Carotene/Xanthophyll
Essential pigment – Chlorophyll
4. What is the mode of nutrition in human beings?
Answer. Holozoic nutrition.
5. Mention the raw materials required for photosynthesis.
Answer. The following raw materials are required for photosynthesis:
(i) Carbon Dioxide: Plants get CO2 from atmosphere through stomata.
(ii)Water: Plants absorb water from soil through roots and transport to leaves.
(iii) Sunlight: Sunlight, which is absorbed by the chlorophyll and other green parts of the plant.
6. What would be the consequences of deficiency of hemoglobin in your body?
Answer.The deficiency of hemoglobin in our body is called anemia. In anemia, the blood is
unable to carry the sufficient amount of oxygen required by the body. So, respiration would be
less and less energy will be available to the body. The hemoglobin deficient person will feel
weak, pale, lethargic and will be unable to perform heavy physical work.
7. Name the green dot like structures in some cells observed by a student when a leaf peel was
viewed under a microscope. What is this green colour due to?
Answer. The green dot-like structures in some cells observed by a student when a leaf peel is
viewed under a microscope are chloroplasts. The green colour is due to the presence of green
pigment, chlorophyll.
8. State any one difference between autotrophic and heterotrophic modes of nutrition.
Answer. In autotrophic nutrition, organisms obtain their food from inorganic substances. In
heterotrophic nutrition, organisms derive their food from organic substances.
9. Give one reason why multicellular organisms require special organs for exchange of gases
between their body and their environment. :
Answer. In unicellular organisms the entire body of the organism is in contact with the
environment hence exchange of materials can take place but, in multicellular organisms the entire
body of the organism is not in contact with the environment and hence simple diffusion is not
helpful.
10. Name the process in plants where water is lost as water vapour. :
Answer. Transpiration is the process when plants loose water as vapour.
Page - 49 -
,11. What is‘translocation’in plants?
Answer. Translocation is the movement of soluble materials, products of photosynthesis from
leaves to other tissues throughout the plant.
12. State the basic difference between the process of respiration and photosynthesis.
Answer. Respiration uses O2 and releases CO2 but in photosynthesis, CO2 is used and O2 is
released.
13. Name the intermediate and the end products of glucose breakdown in aerobic respiration.
Answer.
14. Mention two structural features of small intestine which add to the absorptive capacity.
Answer. Two structural features of small intestine are:
(i) Villi is present to increase the absorptive surface area.
(ii) Lacteals in the villi receive the products of fat digestion.
15. In the experiment “Light is essential for photosynthesis”, why does the uncovered part of
the leaf turn blue-black after putting iodine solution?
Answer. Starch is produced in the uncovered part of the leaf because it is exposed to sunlight
allowing it to photosynthesize, which turns blue-black in presence of iodine solution.
16. Name the component of blood that helps in the formation of blood clot in the event of a cut.
Answer. Platelets help in clotting of blood in the event of a cut.
17. Mention how organisms like bread moulds and mushrooms obtain their food.
Answer. Organisms like bread moulds and mushrooms breakdown the food materials outside the
body and then absorb the nutrients of the bread.
18. What advantage over an aquatic organism does a terrestrial organism have with regard to
obtaining oxygen for respiration?
Answer. The amount of oxygen dissolved in water is very low, as compared to amount of oxygen
in air. Thus, terrestrial organism has to make less efforts to obtain oxygen than an aquatic
organism to obtain oxygen for respiration.
19. Name the two ways in which glucose is oxidised to provide energy in various organisms.
Answer. The two ways in which glucose is oxidised to provide energy in various organisms are
aerobic respiration pathway which uses oxygen to break-down glucose completely into carbon
dioxide and water and some use other pathways that do not involve oxygen which is called
anaerobic respiration pathway.
20. Specify two conditions in which photo-respiration may take place in green plants.
Answer. Two conditions in which photorespiration may take place in green plants are: (i) High
concentration of oxygen and (ii) High temperature
SHORT ANSWER TYPE QUESTIONS[I] [2 MARKS]
21. What are the final products after digestion of carbohydrates and proteins?
Answer. The final product produced after digestion of carbohydrates is glucose and of proteins is
amino acids.
22. What is saliva? State its role in the digestion of food.
Answer. Saliva is a watery fluid secreted by the salivary glands in the mouth. The digestive
Page - 50 -
, functions of saliva include moistening food, and helping to create a food bolus, so it can be
swallowed easily. Saliva contains the enzyme amylase that breaks some starches down into
maltose and dextrin.
23. Explain the process of nutrition in Amoeba.
Answer. The mode of nutrition in Amoeba is holozoic. It feeds on unicellular plant or animal.
The various steps of nutrition are ingestion, digestion, assimilation and egestion. When Amoeba
comes in contact with food particles, it sends out pseudopodia, which engulfs 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 food vacuole. The food vacuole serves as a
temporary stomach secreting digestive juice, this step is known as digestion. The digested food
gets absorbed and diffuses into the cytoplasm and then assimilated. Egestion of undigested food
takes place at any point on the surface of the body.
24. State two differences between arteries and veins.
Answer. Arteries: Arteries carry oxygenated blood, away from the heart except pulmonary
artery. These are thick-walled, highly muscular except arteries of cranium and vertebral column.
Valves are absent. Blood in arteries moves with pressure.
Veins: Veins carry deoxygenated blood, towards the heart except pulmonary veins. These are
thin-walled. Valves are present which provide unidirectional flow of blood.
Blood in veins moves under very low pressure.
25. How are the alveoli designed to maximise the exchange of gases?
Answer.Alveoli are small pouches or sacs like structure. They are surrounded by blood
capillaries. Thus a large amount of air is brought in contact with the air in the lungs. More than
millions of alveoli are present in the lungs. The presence of millions of alveoli in the lungs
provides a very large surface area for the exchange of gases. The availability of large surface area
maximises the exchange of gases.
26. Explain the mechanism of gaseous exchange between tissues and blood.
Answer. 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
lungs has high concentration of oxygen and 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.
27. Describe the mechanism of blood clotting.
Answer. Blood Clotting: It is the mechanism that prevents the loss of blood at the site of an injury
or wound by forming a ‘blood clot’. The blood has platelet cells which circulate around the body
and plug these leaks by helping to clot the blood at these points of injury to prevent it from
excessive bleeding.
28. Why are white blood corpuscles called ‘soldiers’ of the body?
Answer. White blood corpuscles can fight with the disease germs present in the body carried by
blood and help to maintain a healthy body. So, they are called as ‘soldiers’ of the body.
29. Which part of the human heart is considered as pace-maker? Why is it so called?
Answer. Sino-atrial node of the human heart is considered as pacemaker. Sino-atrial node is also
called as pacemaker because it determines the rate of heartbeat by determining the rate of
discharge of cardiac impulse.
Page - 51 -
