Page 104 - NCERT Science Class 10 English Medium

n During the process of respiration, organic compounds such as glucose are broken
down to provide energy in the form of ATP. ATP is used to provide energy for other
reactions in the cell.

n Respiration may be aerobic or anaerobic. Aerobic respiration makes more energy
available to the organism.
n In human beings, the transport of materials such as oxygen, carbon dioxide, food
and excretory products is a function of the circulatory system. The circulatory
system consists of the heart, blood and blood vessels.
n In highly differentiated plants, transport of water, minerals, food and other materials
is a function of the vascular tissue which consists of xylem and phloem.
n In human beings, excretory products in the form of soluble nitrogen compounds
are removed by the nephrons in the kidneys.
n Plants use a variety of techniques to get rid of waste material. For example, waste
material may be stored in the cell-vacuoles or as gum and resin, removed in the
falling leaves, or excreted into the surrounding soil.

E X E R C I S E S

1. The kidneys in human beings are a part of the system for
(a) nutrition. (c) excretion.
(b) respiration. (d) transportation.
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.
3. The autotrophic mode of nutrition requires
(a) carbon dioxide and water. (c) sunlight.
(b) chlorophyll. (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.
5. How are fats digested in our bodies? Where does this process take place?
6. What is the role of saliva in the digestion of food?
7. What are the necessary conditions for autotrophic nutrition and what 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 the alveoli designed to maximise the exchange of gases?
10. What would be the consequences of a deficiency of haemoglobin in our bodies?
11. Describe double circulation of blood in human beings. Why is it necessary?
12. What are the differences between the transport of materials in xylem and phloem?
13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with
respect to their structure and functioning.

Life Processes 99

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