NEET Practice Questions (MCQs) with Answers & Solutions

The NCERT explicitly mentions, 'The breakdown of the protons gradient due to movement through the F0 part of the ATPase enzyme releases enough energy for synthesis of ATP.' This highlights the direct link between the proton gradient and ATP production.

The NCERT states, 'Within the chloroplasts, the membranes are sites for the light reaction, while the chemosynthetic pathway occurs in the stroma.' However, in the summary, it clarifies that 'a proton gradient is created across the membrane of the thylakoid. The breakdown of the protons gradient due to movement through the F0 part of the ATPase enzyme releases enough energy for synthesis of ATP.' This implies that the chemiosmosis, leading to ATP synthesis, occurs across the thylakoid membrane. The question refers to the 'chemosynthetic pathway' which in the summary is referred to as the process involving ATP and NADPH synthesis following the light reaction across the thylakoid membrane. If it means 'carbon fixation' then it is stroma. Given the context of the question following proton gradient, it refers to ATP synthesis part of light reaction, which happens on thylakoid membrane.

The NCERT states that 'Splitting of water molecules is associated with PS II resulting in the release of O2, protons and transfer of electrons to PS II.' The release of oxygen occurs before and independently of the proton gradient breakdown for ATP synthesis. The proton gradient facilitates ATP synthesis via ATPase and its formation is related to electron transport which ultimately leads to NADPH formation.

The proton (hydrogen ion) gradient is created across the thylakoid membrane, meaning protons accumulate within the thylakoid lumen.

The NCERT clearly states, 'The breakdown of the protons gradient due to movement through the F0 part of the ATPase enzyme releases enough energy for synthesis of ATP.' This indicates that the potential energy of the proton gradient is directly harnessed for ATP production.

The NCERT summary states, 'After absorbing light, electrons are excited and transferred through PS II and PS I and finally to NAD forming NADH. During this process a proton gradient is created across the membrane of the thylakoid.' This establishes the direct link between electron transport and proton gradient formation.

The NCERT text states: 'The constantly dividing cells... represent the meristematic phase of growth. The cells in this region are rich in protoplasm, possess large conspicuous nuclei. Their cell walls are primary in nature, thin and cellulosic with abundant plasmodesmatal connections.'

According to the NCERT text, 'The cells proximal (just next, away from the tip) to the meristematic zone represent the phase of elongation. Increased vacuolation, cell enlargement and new cell wall deposition are the characteristics of the cells in this phase.'

The NCERT text specifies: 'Further away from the apex, i.e., more proximal to the phase of elongation, lies the portion of axis which is undergoing the phase of maturation. The cells of this zone, attain their maximal size in terms of wall thickening and protoplasmic modifications.'

The NCERT text states that 'Increased vacuolation, cell enlargement and new cell wall deposition are the characteristics of the cells in this [elongation] phase.' Significant protoplasmic modifications and maximal size are characteristic of the maturation phase, not the elongation phase.