Free Forms and Functions of Plants MCQs with Answers

151. Which of the following pigments is Blue-green in colour?

• A. Chlorophyll a
• B. Chlorophyll b
• C. Chlorophyll c
• D. None of these

Explanation: Chlorophyll a is the most abundant pigment in plants and algae. It is a blue-green pigment that absorbs blue and red light during photosynthesis. Chlorophyll a is responsible for the overall green color of plants.

152. What is reduced in photosynthesis?

• A. Oxygen
• B. Carbon dioxide
• C. Water
• D. Light

Explanation: Correct option is B. During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose.

153. Chlorophylls are found embedded in the _ membrane?

• A. Stroma
• B. Grana
• C. Thylakoid
• D. Intergrana

Explanation: The correct answer for this is "Thylakoid". Since chlorophyll is a pigment present in the chloroplast, It is present and embedded in the "thylakoid" membrane present in "Stroma".

154. Which of the following promotes both leaf and fruit growths?

• A. Auxins.
• B. Gibberellins.
• C. Abscisic acid.
• D. Ethane.

Explanation: Gibberellins promote leaf and fruit growths.

155. Pick the paratonic movement from the following:

• A. Nastic.
• B. Growth.
• C. Turgor.
• D. Tactic.

Explanation: Nastic movements are a type of paratonic movement.

156. It is known that red light_ flowering in the long day plants.

• A. Synchronizes.
• B. Promotes.
• C. Inhibits.
• D. Does not affect.

Explanation: It has been found that red light Inhibits flowering the short day plants but promotes flowering in long day plants.

157. In plants, the red light favours:

• A. Enhancement of cell differentiation
• B. Maturation of the cells
• C. Elongation of cells
• D. Enhancement of cell division

Explanation: Explanation:Red light favours elongation of cells and blue light enhances cell division but retards cell enlargement.When red light can influence the differentiation of certain cell types in plants, it is not the primary effect of red light.Red light is not known to have a significant effect on the maturation of cells in plants.Red light is also not known to have a direct effect on cell division in plants, although it can indirectly influence cell division by promoting plant growth and providing the necessary conditions for cell division to occur.

158. Name the external factor of growth in plants.

• A. Carbon dioxide.
• B. Water.
• C. Hormones.
• D. Nutrition.

Explanation: Environmental factors that affect plant growth include light, temperature, water, and humidity.

159. The dew drops on tips of grass leaves is an example of:

• A. Infestation.
• B. Exudation.
• C. Bleeding.
• D. Imbibition.

Explanation: Closely associated with root pressure is a phenomenon called guttation or exudation. It is the loss of liquid water through water secreting glands or hydrathodes.

160. Chlorophylls absorb mainly _ wave length.

• A. Yellow.
• B. Violet-blue.
• C. Green.
• D. Indigo.

Explanation: All plants have chlorophyll a which absorbs most strongly at ~450 nm, or a bright blue color.