Botany MCQs for NEET — Practice Questions with Answers

The fixation and reduction of CO₂ in the Calvin cycle (also known as the dark reaction) occur in the presence of ATP and NADPH, which are generated during the light reactions of photosynthesis. ATP provides the necessary energy, while NADPH provides the reducing power for the conversion of CO₂ into glucose.

In plants, sugar is transported through the phloem vessels primarily in the form of sucrose. Sucrose is a disaccharide composed of glucose and fructose. It is the main form of sugar transported because it is more stable and less reactive than glucose.

Photolysis of water in photosynthesis involves the splitting of water molecules into oxygen, protons, and electrons. This process is catalyzed by the oxygen-evolving complex (OEC) of photosystem II, which requires manganese (Mn++) and chloride (Cl-) ions to function properly.

Violaxanthin is a carotenoid and is known to be a precursor in the biosynthesis of abscisic acid (ABA), which is a plant hormone involved in various plant developmental processes and stress responses.

Phycobilins are pigments found in cyanobacteria and certain algae that contain open-chain tetrapyrrole rings (also known as open pyrrole rings). This structure is different from the closed tetrapyrrole ring found in chlorophylls.

Dimorphic chloroplasts, which refer to the presence of two different types of chloroplasts in the same plant, are present in C4 plants such as Zea mays (maize), Saccharum officinarum (sugarcane), and Sorghum bicolor. These plants use a specialized form of photosynthesis to efficiently fix carbon.

The red pigment in tomatoes is primarily due to a compound called lycopene. Lycopene is a type of carotenoid, which is a natural pigment that is responsible for the red and pink colors in various fruits and vegetables. It is also a powerful antioxidant.