CBSE Questions for Class 11 Medical Biology Photosynthesis In Higher Plants Quiz 12 - MCQExams.com

• ATP as we know is the energy currency of a cell; the phosphate bond that is present in the ATP when broken releases large amount of energy which can be used by the cell.
• After the ATP molecule has released energy it will give break down to ADP and P which will be released in the cytoplasm or the matrix of organelles where it is used.
• These ADP and P are used as subtrates when the ATP is to be generated again by the cell by the reactions such as glycolysis, kerb cycle, chemiosmotic phosphorylation.
• NAD is an electron acceptor that accepts electrons that are released from the glycolysis reaction and also during the kerb cycle.
• After they have accepted the electron they transfer the electron to the electron transfer chain that are transported through various complexs in the chain and produce energy.
• The NADH is transformed to NAD again and is ready to be used again.
• CoA that is used for the formation of acetyl CoA from the pyruvate is also regenerated in the kerb cycle and released in the cytoplasm so that it can again be used to decarboxylate pyruvic acid and used for the oxidation of fatty acid.
• Therefore even if small amount of these componets are present in the cell the cell can carry out its metabolic activities as these components after being used are regenerated again and ready to be used o no hinderance occurs in the pathway of metabolism.
• Therefore the answer 'rapidly recycle these compounds' is correct.
  

• Bundle sheath cells have thick walls.
• They have little or no intercellular spaces and are impervious to gases.
• PEP carboxylase is present in the mesophyll cells.
• The chloroplasts are present in a higher density and close to the vascular tissues.

  In the given question, the correct statements are as follows:

(i) F1 headpiece contains the site for the synthesis of ATP from ADP+Pi.

(ii) F0 part forms the channel through which protons cross the inner membrane.

(iii) For each ATP produced, 2H+ pass through F0 from the intermembrane space to the matrix down the electrochemical proton gradient.

So, the correct answer is '(i),(ii) and (iii)'.

• In the electron transport, while the membrane or lamellae of the grana have both PS I and PS II the stroma lamellae membranes lack PS II as well as NADP reductase enzyme.
• The excited electron does not pass on to NADP+ but is cycled back to the PSI complex through the electron transport chain. 
• Hence, Electron vacancy in PSI in ETS is replaced by PSII. 
• So, the correct answer is 'PSII'.

1. Photorespiration (Photosynthetic carbon oxidative or PCO cycle) is the light dependent process of oxygenation of rbulose-1, 5-biphosphate (RuBP) and release of $$CO_{2}$$ by the photosynthetic organs of a plant.
2.  Under normal conditions, in Calvin cycle, carboxylation of RuBP takes place whereas during photorespiration instead of carboxylation , oxygenation of RuBP takes place. 
3. This is due to abnormal behavior of enzyme RuBisCO, which at high temperature (more than $$35^{o}C$$), functions as oxygenase (instead of carboxylase). Instead of fixing $$CO_{2}$$ it performs oxygenation of RuBP to produce a 3- carbon phosphoglyceric acid (PGA) and a 2- carbon phosphoglycolate. It is the first reaction of photorespiration and can be represented as :