Free Forms and Functions of Plants MCQs with Answers

141. Magnesium is an important nutrient in plants for the formation of:

• A. Proteins
• B. Lipids
• C. Chlorophylls
• D. Enzymes

Explanation: Magnesium is a key component of chlorophyll, the green colouring material of plants, and is vital for photosynthesis.

142. Synthesis of ATP during photosynthesis takes place at the region:

• A. Stroma
• B. Thylakoid
• C. Matrix
• D. Cisternae

Explanation: This is where the components of the electron transport chain are located.

143. Which of the following molecules are released after completion of light reaction and then utilized in the dark reaction of photosynthesis?

• A. ATP and NADP+
• B. ADP and NADP+
• C. ADP and NADPM
• D. ATP and NADPH

Explanation: After the completion of light reactions in photosynthesis, the molecules released and utilized in the dark reactions are ATP and NADPH (Option D). These molecules provide the energy and reducing power required for the Calvin cycle, which is part of the dark reactions.

144. When light falls on P-700, which event is likely to occur?

• A. It induces photolysis
• B. Gains Hydrogen
• C. Accept elecrons
• D. It is oxidised

Explanation: When light falls on P-700, it is oxidised. The electrons are removed.

145. Which are the end products of light reactions of photosynthesis?

• A. ATP and NADPH
• B. ATP and glucose
• C. Glucose and NADP
• D. ATP and water

Explanation: These molecules are generated during the light reactions and are used in the subsequent dark reactions to convert carbon dioxide into glucose.

146. Which of the following is a copper containing protein in electron transport chain?

• A. Plastoquinone
• B. Cytochrome - C
• C. Plastocyanin
• D. Ferredoxin

Explanation: It serves as an electron transfer agent between the cytochrome complex which follows Photosystem II and the entry point to Photosystem I of the non-cyclic electron transfer process. The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH2 to molecular oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.

147. Deficiency of which element causes yellowing in plants?

• A. Magnesium
• B. Iron
• C. Chlorine
• D. Oxygen

Explanation: "The explanation for this question will be added soon!".

148. The percentage of light absorbed by the leaf is

• A. 0.2
• B. 0.15
• C. 0.05
• D. 0.01

Explanation: Only 1% of light is absorbed by the leaf.

149. Which of the following is incorrect for ascent of sap?

• A. Water potential
• B. Cohesion tension
• C. Root pressure
• D. Imbibition

Explanation: "The explanation for this question will be added soon!".

150. The attraction between water molecules and the cell wall of xylem is termed as:

• A. Cohesion
• B. Tension
• C. Adhesion
• D. Imbibition

Explanation: Option A: Cohesion refers to the attraction between water molecules themselves, which allows them to stick together and form a continuous column in the xylem. Option B: Tension refers to the force that pulls water up through the xylem, which is caused by transpiration at the leaves. Option C: Adhesion is a molecular attraction between "unlike" molecules. In the case of the xylem, adhesion occurs between water molecules and the molecules of the xylem cell walls. Cohesion is a molecular attraction between "like" molecules. In water, cohesion occurs due to hydrogen bonding between the water molecules.Option D: Imbibition refers to the process by which a solid absorbs water, such as a seed swelling when it takes up water.