Photosynthesis MCQs for NEET — Botany Questions with Answers

Sugarcane is one of the most efficient plants in converting solar energy into biomass. It has a high net productivity of 2-4 kg/m²/yr or even higher, making it the correct answer. Sugarcane's efficiency is due to its C4 pathway of photosynthesis, which is more efficient under high light intensity and temperature conditions.

The quantum requirement in photosynthesis refers to the number of photons needed to release one mole of O₂. It is a measure of the efficiency of photosynthesis in converting light energy into chemical energy. Thus, option o2 is the correct answer.

The Calvin cycle, also known as the C3 cycle, is a series of biochemical redox reactions that take place in the stroma of chloroplasts in photosynthetic organisms. It is referred to as reductive carboxylation because it involves the reduction of carbon dioxide into glucose. This process uses ATP and NADPH produced during the light-dependent reactions of photosynthesis.

Maximum photosynthesis typically occurs under red light. Red light (around 680 nm) is most effectively absorbed by chlorophyll a, the main pigment involved in photosynthesis. Thus, red light drives the highest rate of photosynthesis compared to other wavelengths.

In C₄ plants, the Kranz anatomy is characterized by bundle sheath cells that lack grana and mesophyll cells that contain grana. This specialization allows for the efficient functioning of the C₄ photosynthetic pathway, which minimizes photorespiration and maximizes photosynthetic efficiency.

Chlorophyll a is absent in bacteria. Bacteria use different pigments such as bacteriochlorophylls for photosynthesis, which are distinct from the chlorophylls found in plants, algae, and cyanobacteria.

Photorespiration begins in the chloroplast, when rubisco attaches oxygen to RuBP in its oxygenase reaction. Two molecules are produced in this reaction: a three-carbon compound, 3-PGA, and a two-carbon compound, phosphoglycolate.

The Law of Limiting Factors was formulated by F. F. Blackman. This law states that the rate of a physiological process will be limited by the factor that is in the shortest supply. In the context of photosynthesis, this means that the rate can be limited by light intensity, carbon dioxide concentration, or temperature, depending on which is the least available or most restrictive at any given time.