Life Processes NCERT Class 10 Science lesson 6 Questions And Answers

 Life Processes

Exercises

1. The kidneys in human beings are a part of the system for 
            a) nutrition                          c) excretion.
            b) respiration                      d) transportation.

Answer:    

        c) excretion.

2. The xylem in plants are responsible for
            a) transport of water.            c) transport of amino acids.
            b) transport of food.             d) transport of oxygen.

Answer: 

        a) transport of water.

3. The autotrophic mode of nutrition requires
        a) carbon dioxide and water        c) sunlight
        b) chlorophyll.                              d) All of the above.

Answer: 

        d) All of the above

4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in 
        a) cytoplasm.                             c) chloroplast.
        b) mitochondria.                        d) nucleus.

Answer: 

        b) mitochondria.

5. How are fats digested in our bodies? Where does this process take place? 

Answer:

     The pancreas secretes pancreatic juice which contains enzymes like like trypsin for digesting proteins and lipase for breaking down emulsified fats. The walls of the small intestine contain glands which secrete intestine juice. The enzymes present in it finally convert the proteins to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.

6. What is the role of saliva in the digestion of food?

Answer:

        The food we ingest is its complex nature. If it is to be absorbed from the alimentary canal, ti has to be broken in to smaller molecules. This done with the help of biological 

7. What are the necessary conditions for autotrophic nutrition and what are its by-products?

Answer:

    Carbon an energy requirements of the autotrophic organism are fulfilled by photosynthesis. It is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy. This materials is taken in the form of carbon dioxide and water which is converted into carbohydrates  in the presence of sunlight and chlorophyll. Carbohydrates are utilised for providing energy to the plants. 

8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Answer:

    Aerobic Respiration

        The Break down of food in mitochondria to make energy(ATP) in the presence of oxygen is known as aerobic respiration.

    Anaerobic Respiration

        The break down  of glucose into pyruvate in cytoplasm and further conversation of pyruvate into ethanol and carbon dioxide in the absence of oxygen is known as anaerobic respiration. 

   Yeast is example of organisms that use anaerobic mode of respiration

9. How are the alveoli designed to maximise the exchange of gases?

Answer:

    The alveoli provide a surface where the exchange of gases can take place. The walls of the alveoli contain and extensive network of blood-vessels. When we breathe in, we lift our ribs and flatern our diaphragm, and the chest cavity becomes larger as a result. Because of this, air is sucked into the lungs and fills the expanded alveoli. The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in the alveolar air is taken up by blood in the alveolar blood vessels to be transported to all the cells in the body. 

10. What would be the consequences of a deficiency of haemoglobin in our bodies?

Answer:

    In human beings, the respiratory pigment is haemoglobin which has a very high affinity for oxygen. This pigment is present in red blood corpuscles and carries oxygen to different cells in our whole body.  Due to its deficiency our body's need of oxygen will not be full filled which can give rise to different diseases and symptons.

11. Describe double circulation of blood in human beings. Why is it necessary?

Answer:

    Fishes, have only two chambers to their hearts,  and the blood is pumped to gills, is oxygenated there, and passes directly to the rest of the body. Thus, blood goes only once through the heart in the fish during one cycle of passage through the body. On the other hand, it goes through the heart twice during each cycle in other vertebrates. This is known as double circulation.

12. What are the differences between the transport of materials in xylem and phloem?

Answer:

    Transport of material in xylem

•         In xylem tissue, vessels and tracheids of the roots, stems and leaves are interconnected to form a continuous system of water conducting channels reaching all parts of the plant.
•         The water which is lost through the stomata is replaced by water from the xylem vessels in the leaf. 
•         Transpiration pull becomes the major driving force in the movement of water in the xylem.

    Transport of material in phloem

•         The transport of soluble products of photosynthesis is called translocation and it occurs in the part of the vascular tissue know as phloem.
•         Besides the products of photosynthesis, the phloem transports amino acids and other substances.
•         The translocation in phloem is achieved by utilising energy.  
•         Materials like sucrose is transferred in to phloem tissue using energy from ATP.

13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Answer:

       Alveoli

•    Within lungs, the passage divides into smaller and smaller tubes which finally terminates in ballon-link structures which are alveoli.
•    The alveoli provides a surface where the exchange of gases can take place.
•    The walls of alveoli contains an extensive network of blood-vessels.
•    The air is sucked into the lungs and fills the alveoli. The blood brings carbon dioxide from the rest of the body and release into the alveoli, and the oxygen in the alveolar air is taken up by the air blood.

        Nephrons

•    The basic filtration unit in the kidneys, is a cluster of very thin-walled blood capillaries. 
•    Each capillary cluster in the kidney is associated with cup-shaped end of coiled tube called Bowman's capsule that collects the filtrate.
•    Each kidney has large number of these filtration units called nephrons packed close together.
•    Some substances in the initial filtrate, such as glucose, amino acids, salts and a major amount of water, are selectively re-absorbed as the urine flows along the tube.