Photosynthesis In Higher Plants(11th And 12th > Biology ) Questions and answers for exam Preparation

11th And 12th > Biology

PHOTOSYNTHESIS IN HIGHER PLANTS MCQs

Total Questions : 60 | Page 1 of 6 pages

Which of the following does not occur during the Calvin cycle?

carbon fixation
oxidation of NADPH
release of oxygen
regeneration of the CO2 acceptor

Discuss Question

Answer: Option C. -> release of oxygen
:
C
Release of Oxygen in photosynthesis is during the photolysis of water in the non-cyclic photophosphorylation.

Question 2.

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

NADP $^{+}$ $\to$ O $_{2}$ $\to$ CO $_{2}$
H $_{2}$ O $\to$ NADP $^{+}$ $\to$ Calvin cycle
NADP $^{+}$ $\to$ chlorophyll $\to$ Calvin cycle
H $_{2}$ O $\to$ photosystem I $\to$ photosystem II

Discuss Question

Answer: Option B. -> H

_{2}

\to

NADP

^{+}

\to

Calvin cycle
:
B
Electrons flow from water through the photosystem II, electron transport chain, and photosystem I to NADP

^{+}

. The electrons of NADPH thus formed are then used in the Calvin cycle.

Question 3.

Which statement describes the functioning of photosystem II?

Light energy excites electrons in the electron transport chain in a photosynthetic unit.
The excitation is passed along to a molecule of P700 chlorophyll in the photosynthetic unit.
The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+
The electron vacancies in P680 are filled by electrons derived from water.

Discuss Question

Answer: Option D. -> The electron vacancies in P680 are filled by electrons derived from water.
:
D
When light falls in photosystem II, electrons get excited and are transported through an electron transport chain to photosystem I. Water is split, oxygen is released and electrons are transferred to photosystem II.

Question 4.

What is the primary function of the Calvin cycle?

use ATP to release carbon dioxide
use NADPH to release carbon dioxide
split water and release oxygen
synthesize simple sugars from carbon dioxide

Discuss Question

Answer: Option D. -> synthesize simple sugars from carbon dioxide
:
D
In the Calvin cycle, carbon dioxide is fixed to an organic substrate and then sugars are formed.This is a biosynthetic cycle.

Question 5.

How is photosynthesis similar in C4 and CAM plants?

In both cases, only photosystem I is used.
Both types of plants make sugar without the Calvin cycle.
In both cases, rubisco is not used to fix carbon initially.
Both types of plants make most of their sugar in the dark.

Discuss Question

Answer: Option C. -> In both cases, rubisco is not used to fix carbon initially.
:
C
C4 and CAM plants are plants that use certain special compounds to gather carbon dioxide (CO ₂) during photosynthesis. Using these compounds allows these plants to extract more CO ₂from a given amount of air, helping them prevent water loss in dry climates.

Question 6.

During what stage of photosynthesis is O $_{2}$ produced?

cyclic photophosphorylation
the light-dependent reactions involving photosystems I and II
carbon fixation
the Krebs cycle

Discuss Question

Answer: Option B. -> the light-dependent reactions involving photosystems I and II
:
B
This is due to the splitting of the water molecule during the non-cyclic photophosphorylation.

Question 7.

Solar energy is passed from one pigment to the other until it is concentrated into one particular ______ molecule, the reaction-center chlorophyll.

red carotenoid
orange carotenoid
yellow carotenoid
chlorophyll a

Discuss Question

Answer: Option D. -> chlorophyll a
:
D

Chlorophyll a is called the primary pigment or the reaction centre.

Question 8.

In the thylakoid membranes, what is the main role of the antenna pigment molecules?

split water and release oxygen to the reaction-center chlorophyll
harvest photons and transfer light energy to the reaction-center chlorophyll
synthesize ATP from ADP and Pi
transfer electrons to ferredoxin and then NADPH

Discuss Question

Answer: Option B. -> harvest photons and transfer light energy to the reaction-center chlorophyll
:
B
These are also called as the accessory pigments.

Question 9.

Which of the following statements is true with regard to the light reaction of photosynthesis?

In PS – II reaction centre, chlorophyll – a has an absorption peak of 700 nm, hence called p700
In PS – I, the reaction centre chlorophyll –a has an absorption maxima at 680 nm and is called p680
The splitting of water molecule is associated with PS – I
Photo systems – I and II are involved in Z – scheme.

Discuss Question

Answer: Option D. -> Photo systems – I and II are involved in Z – scheme.
:
D

Photophosphorylation is the synthesis of ATP from ADP and inorganic phosphate in the presence of sunlight. When the two photo systems, work in a series, first PS – II and then the PS – I, a process called non-cyclic phosphorylation occurs in the two photosystems that are connected through an electron transport chain in Z - scheme. (due to the shape of path of electrons flow). Both ATP and NADH + H⁺ are synthesized by this kind of electron flow.

Question 10.

Which enzyme fixes CO₂ in Calvin cycle?