NCERT class 10 Life processes solution of Exercise
Kidneys in human beings are a part of the system for
2. The xylem in plants are responsible for
Ans. Transport of water
3. The autotrophic mode of nutrition requires
Ans: All (a.CO2 and water b. Chlorophyll c. Sunlight)
4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
5. How are fats digested in our bodies? Where does this process take place?
Ans: Fats are a long chain of fatty acids and are insoluble in water. Lipase from Pancreas breaks down the long chains into simpler fatty acid. But it can not do this unless the fat is immersed in water. The liver secretes Bile juice. It emulsifies the fats through the presence of both lipophilic bond and lipophobic bond. Now Lipase breaks them into simple fatty acid. A simple fatty acid is readily absorbed by the intestinal Villi.
All these enzymes are secreted in the small intestine and also villi are present only in the small intestine, so the absorption of fats occurs only in the small intestine.
6. What is the role of saliva in the digestion of foods?
Ans: Saliva lubricates the food for its easy passage into the stomach. More ever Saliva contains an enzyme called salivary amylase also called ptyalin. It breaks down the complex starch into simple sugars. Simple sugars are easily absorbable by the intestine.
7. What are the necessary conditions for autotrophic nutrition and what are its by-products?
Ans: Presence of sunlight, Carbon dioxide, and water, chlorophyll pigments are necessary conditions for autotrophic nutrition which happens through photosynthesis. If plant lack any of these condition photosynthesis will stop.
By-products: carbohydrates and oxygen are its by-products.
8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
9. How are alveoli designed to maximise the exchange of gases?
10. What would be the consequences of a deficiency of haemoglobin in our bodies?
Ans: Low oxygenation of blood < Lesser rate of respiration < Lesser energy in the body < Increased breathing rate, increased hunger
Chronic deficiency of Haemoglobin < Anaemia
High Carbon dioxide in blood < Systemic acidosis
11. Describe the double circulation of blood in human beings. Why this is necessary.
Ans: Double circulation means same blood passes the heart twice. Humans have two atria and two ventricles.
The right atrium receives the impure or deoxygenated blood from the body and transfers it to the right ventricle. Right ventricle pushes this blood with new force to the lung. In lungs blood gets oxygenated. It enters into the left atrium and is passed to the left ventricle. The left ventricle is thicker and more muscular so that it pushes the blood throughout the whole body.
12. What are the differences between the transport of material in xylem and phloem?
13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structures and functioning.