31 Years NEET Previous Year Questions: Photosynthesis in Higher Plants - 2 - NEET MCQ

ATP molecules produced in the light reaction are used in the dark reaction to fix CO₂ to form organic compound.

Maize is a C₄ plant carrying out Hatch and Slack pathway. These plants show Kranz anatomy and overcome photorespiration.

2 ATP are required during conversion of PGA to 1, 3-diphosphoglyceric acid and 1 ATP during conversion of glyceraldehyde phosphate to ribulose biphosphate. 2NADH₂ molecules are utilised for converting 1, 3-diphosphoglyceric acid to glyceraldehyde phosphate.

Each turn of Calvin cycle generates one carbon atom hence six turns of the cycle is required to generate one molecule of hexose sugar glucose.

 RuBP carboxylase fixes CO₂ in C₃ plants. Hydrogenase catalyses addition of hydrogen. 

RUBISCO  is the enzyme involved in Calvin cycle. Nitrogenase catalyses nitro- genation. Invertase catalyses breaking of sucrose to glucose and fructose.

Photosystem I is the second photosystem in the photosynthetic light reactions of algae, plants and some bacteria. Photosystem I is so named because it was discovered before photosystem II. It produces NADPH₂.

In dark phase of calvin cycle of photosynthesis the CO₂ is reduced to Glucose in stroma of chloroplast, making use of the ATP & NADPH₂, (available from light phase).

Photosynthesis takes place only in the visible part (400 - 700 nm wavelength) of electromagnetic radiations. Hence this component comprises the photosynthetically active radiation.

The principle of limiting factors was formulated by Blackmann (1905). It states that when a process is conditioned as to its rapidity by a number of separate factors, the rate of process is limited by the pace of slowest factor.

Photorespiratory loss of CO₂ occurs when RUBISCO starts functioning as an oxygenase instead of carboxylase  under conditions of  high O₂ and low CO₂. It involves three organelles chloroplast, mitochondria and peroxisomes. Half of the photosynthetically fixed carbon (in the form of RUBP) may be lost into the atmosphere through this process and no ATP formation occurs.

Anatomy of leaves of C_4– plant is called kranz anatomy. In the mesophyll cells of these plants pallisade tissue is absent.

The only process that occurs in both cyclic and non-cyclic photophosphorylation is the formation of ATP.

P700 consists of a chl a and chl b molecules and is named after maximum absorption by pigment or photocentre at that wavelength.