In Botany's class, the teacher explains, the synthesis of one glucose requires 30 ATPs in C 4 plants and only 18 ATPs in C 3 plants. The same teacher explains the C 4 plants are more advantageous than C 3 plants. Can you identify the reason for this contradiction?

C 4 cycle of CO 2 fixation is more efficient than the C 3 cycle as in C 3 plants, the rate of photosynthesis decreases under high temperatures and has a high rate of photorespiration whereas it is very low in C 4 plants. C 4 plants can survive in high temperatures of hot habitat as they have a special anatomical feature in their leaves called Kranz anatomy. By this feature, C 4 plants can prevent photorespiration and thus successfully survive in a hot habitat without affecting the rate of photosynthesis.

When there is plenty of light and a higher concentration of O 2 , what kind of pathways does the plant undergo? Analyse the reasons.

When there is plenty of light and a high concentration of O 2 plants undergo photorespiration. This process occurs in C 3 plants only. In this process, RuBP carboxylase that joins carbon dioxide to RuBP functions as an oxygenase. Due to this carbon dioxide gets attached to the binding site of the enzyme and RuBP is oxidised. On oxidation, RuBP releases one molecule of C 3 compound, PGA that enters the C 3 cycle and one molecule of a two-carbon compound phosphoglycolate. Phosphoglycolate immediately changes into glycolate. The glycolate leaves the chloroplast and enters the peroxisome. Here glycolate is oxidised into glycine. Further oxidation of glycine takes place inside the mitochondria where two molecules of glycine interact and give rise to a molecule of serine and carbon dioxide each.

E M B I B E

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 2

MEDIUM

11th Tamil Nadu Board

IMPORTANT

Earn 100

Which chlorophyll molecule does not have a phytol tail?

50% studentsanswered this correctly

Important Questions on Photosynthesis

MEDIUM

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 3

The correct sequence of flow of electrons in the light reaction is:

MEDIUM

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 4

For every CO₂molecule entering the C₃ cycle, the number of ATP and NADPH required:

MEDIUM

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 5

Identify the true statement regarding the light reaction of photosynthesis?

HARD

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 6

Two groups (A and B) of bean plants of similar size and same leaf area were placed in identical conditions. Group A was exposed to the light of wavelength 400-500nm and group B to the light of wavelength 500-550nm. Compare the photosynthetic rate of the 2 groups giving reasons.

MEDIUM

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 7

A tree is believed to be releasing oxygen during nighttime. Do you believe in the truthfulness of this statement? Justify your answer by giving reasons?

HARD

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 8

Grasses have an adaptive mechanism to compensate photorespiratory losses- Name and describe the mechanism.

MEDIUM

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 9

In Botany's class, the teacher explains, the synthesis of one glucose requires 30 ATPs in C₄ plants and only 18 ATPs in C₃ plants. The same teacher explains the C₄ plants are more advantageous than C₃ plants. Can you identify the reason for this contradiction?

MEDIUM

11th Tamil Nadu Board

IMPORTANT

Biology Botany Standard 11>Chapter 13 - Photosynthesis>Evaluation>Q 10

When there is plenty of light and a higher concentration of O₂, what kind of pathways does the plant undergo? Analyse the reasons.