NCERT Class 11-Biology: Chapter –13 Photosynthesis in Higher Plants Part 6

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Question 18:

Observe the diagram and answer the following.

Chapter 13 Question 18 - Diagram and Answer the Following

Diagram and Answer the Following

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a. Which group of plants exibits these two types of cells?

b. What is the first product of cycle?

c. Which enzyme is there in bundle sheath cells and mesophyll cells?


(a) Monocot plants show bundle sheath cells and mesophyll cells.

(b) Oxaloacetic acid

(c) PEP carboxylase or PEP case.

Question 19:

A cyclic process is occurring in plant, which is light dependent, and needs. This process doesn’t produce energy rather it consumes energy.

a. Can you name the given process?

b. Is it essential for survival?

c. What are the end products of this process?

d. Where does it occur?


(a) Photorespiration

(b) It is not essential for survival.

(c) Hydrogen peroxide

(d) It occurs in chloroplast, mitochondria and peroxisome.

Question 20:

Suppose Euphorbia and Maize are grown in the tropical area.

a. Which one of them do you think will be able to survive under such conditions?

b. Which one of them is more efficient in terms of photosynthetic activity?

c. What difference do you think are there in their leaf anatomy?


(a) Euphorbia is a CAM plant. It fixes during night and uses it in daytime. It will be able to survive in hot tropical climate. Maize is a tropical plant. It undergoes cycle and can easily survive in hot climate.

(b) Maize being a plant is more efficient in terms of photosynthetic activity plants have low compensation point and rate of carbon assimilation is rapid. Rate of photorespiration is negligible. Plants can perform photosynthesis even when the stomata are closed.

(c) Euphorbia has large sized succulent cells and stomata having reniform guard cells closed during the day. Maize plant leaves have kranz anatomy. Stomata possess dumbbell shaped guard cells. The stomata remain open during the day.

Long Answer Type Questions

Question 1:

Is it correct to say that photosynthesis occurs only in leaves of a plant? Besides leaves, what are the other parts that may be capable of carrying out photosynthesis? Justify.


The photosynthesis may also occur in this part if the part of the plant is green.

Therefore, it’s wrong to say that only in plant leaves do photosynthesis occur. Most of the other components of the plant can be photosynthesized. Examples include

(a) Chlorophyll roots of Trap and Timisoara and photosynthesis.

(b) The stem is changed into a fleshy green structure in Opuntia and the leaves are altered in spines to reduce transpiration. Photosynthesis occurs in the stem of these plants. Opuntia’s modified stem is named phylloclade.

(c) Sepals are green and perform photosynthesis at most plants.