Q6 of 70 Page 73

State any four differences between photosynthesis and respiration.











Photosynthesis



Respiration



1) Carbon dioxide is used up in this process with the release of oxygen.


It mainly occurs in green plants and some bacteria.


The glucose produced in this process is utilized by the plants.


This results in a gain of dry weight of plants.



1) In this, oxygen is used in return for carbon dioxide which is released.


2) It occurs in all living organisms.


3) On the other hand, glucose is broken down to obtain energy.


This results in loss of plant’s dry weight.




Photosynthesis is an anabolic process which takes water and carbon dioxide to produce oxygen and high energy bond glucose. On the other hand, respiration is a catabolic process that breaks down glucose into lower energy molecules.


More from this chapter

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4

Are the following statements true or false? Give reason in support of your answer.

(a) The rate of photosynthesis continues to rise as long as the intensity of light rises.


(b) The outside atmospheric temperature has no effect on the rate of photosynthesis.


(c) If you immerse a leaf intact on the plant in ice cold water, it will continue to photosynthesize in bright sunshine.


(d) Destarching of the leaves of a potted plant can occur only at night.


(e) The starting point of carbon cycle is the release of CO2 by animals during respiration.


(f) If a plant is kept in bright light all the 24 hours for a few days, the dark reaction (biosynthetic phase) will fail to occur.


(g) Photosynthesis is considered as a process supporting all life on earth.

 5

Given below are five terms. Rewrite the terms in the correct order so as to be in logical sequence with regard to photosynthesis: (i) water molecules, (ii) oxygen, (iii) grana, (iv) hydrogen and hydroxyl ions, (v) photons.

 7

"Oxygen is a waste product of photosynthesis." Comment.

 8

Why is it necessary to place a plant in the dark before starting an experiment on photosynthesis? Explain.