Free Plant Nutrition and Transport MCQs with Answers

91. Carotenoids absorb light of:

• A. Yellow-orange range
• B. Yellow-red range
• C. Orange-red range
• D. Blue-violet range

Explanation: Carotenoids are one of the accessory pigments in the chloroplasts which absorb light in the Blue-Green and Violet range.

92. Chlorophyll 'a' and chlorophyll 'b' differ in one of the functional group. Chlorophyll 'a' has:

• A. -CHO
• B. -OH
• C. -CH3
• D. -NH2

Explanation: The only difference between chlorophyll-a and b is that chlorophyll-a has methyl (CH3) on the 2nd pyrrole ring and whereas chlorophyll-b has an aldehyde (-CHO) at this point.

93. Glycerate-3-phosphate in the presence of ATP and reduced NADP from light dependent stage is reduced to:

• A. 3-carbon compound
• B. Ribulose bisphosphate
• C. 5-carbon compound
• D. 6-carbon compound

Explanation: Glycerate-3-phosphate, being a carboxylic acid, gets reduced to glyceraldehyde phosphate which is a 3-carbon compound.

94. In plants, which sugar is transported from source to sink through sieve tubes?

• A. Glucose
• B. Sucrose
• C. Fructose
• D. None of the above

Explanation: Factual recall;Glucose is the monosaccharide, that makes up the disaccharide sucrose along with fructose, whereas sucrose is the form, in which sugar is transported from source to sink. Sucrose is broken down to its constituents and then used by tissue cells.

95. Given figure shows:

• A. Structure of a Lenticel
• B. Hydathode showing gaseous vapour exchange
• C. Fungus reproducing by spore formation
• D. Algae reproducing by spore formation

Explanation: The figure shows the structure of 'Lenticel', which facilitates gaseous exchange and transpiration. These are aerating pores in the bark of woody trees. These are surrounded by loosely arranged thin walled complementary cells, enclosing intercellular spaces for gaseous exchange.

96. The _ describes how water and dissolved chemicals are carried through the cell wall and intercellular gaps of plants.

• A. Apoplast Theory
• B. Symplast Theory
• C. Vacuolar Theory
• D. Cytoplasmic Theory

Explanation: The theory that describes how water and dissolved chemicals are carried through the cell wall and intercellular gaps of plants is called the **Apoplast Theory** (Option A).In the Apoplast Theory, water and solutes move through the non-living, porous spaces outside the plasma membrane (cell wall and intercellular spaces) without entering the living protoplasts of the cells. This pathway includes the cell walls, spaces between cells, and the plant's vascular tissue.The Symplast Theory (Option B), on the other hand, describes the movement of water and solutes through the living cytoplasm of the plant cells, where they pass from one cell to another through plasmodesmata.The Vacuolar Theory (Option C) and Cytoplasmic Theory (Option D) are not recognized theories related to the movement of water and dissolved chemicals in plants.

97. Autotrophic mode of nutrition in an organism depends upon:

• A. Saprotrophic mode
• B. Parasitic mode
• C. Photosynthesis mode
• D. Obligate mode

Explanation: Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy, using carbon dioxide and water to produce glucose and oxygen. This process is vital for life on Earth, as it provides oxygen and is the foundation of the food chain. Autotrophic mode of nutrition in an organism depends upon the photosynthetic mode.

98. The epidermis of the xerophytes is covered with a waxy layer called:

• A. Cellulose
• B. Cuticle
• C. Chitin
• D. Lignin

Explanation: Cellulose is a tough, fibrous, and water-insoluble polysaccharide that plays an integral role in keeping the structure of plant cell walls stable. Therefore, A is incorrect. The cuticle is a barrier coating the outer surface of epidermal cells of organs of the aerial parts of the plants. It protects against water loss, various abiotic and biotic stress. Therefore, B is correct. Chitin is a fibrous substance consisting of polysaccharides and it is the major constituent in the exoskeleton of arthropods and the cell walls of fungi. Therefore, C is incorrect. Lignin is an important organic polymer that is abundant in the cell walls of some specific cells. It has many biological functions such as water transport, mechanical support, and resistance to various stresses. Therefore, D is incorrect.

99. Which is least important in photosynthesis?

• A. Red light
• B. Blue light
• C. Sunlight
• D. Green light

Explanation: Greenlight range spectrum is considered as least effective for the process of photosynthesis: The wavelength of green light is thought to be the least efficient for photosynthesis. If the plants are exposed to green wavelengths during photosynthesis, the rate of photosynthesis will be the slowest. This is due to the presence of chlorophyll, a green pigment. Instead of being absorbed by the chlorophyll, the green light is transmitted and reflected. The best visible light wavelengths for photosynthesis are blue (425-450 nm) and red (600-700 nm).

100. All the flowers come at the same level due to equal size of their pedicels in

• A. corymbs
• B. umbel
• C. catkin
• D. panicle

Explanation: The pedicel is a stalk or stem that supports a single flower. It connects the single flower to the inflorescence. It is usually seen in pedicellate flowers (e.g., Roses). The flowers without pedicels are called sessile flowers (e.g., Sunflower).In an umbel, each of the pedicels initiates from about the same point at the tip of the peduncle, giving the appearance of an umbrella-like shape.