CBSE Questions for Class 11 Medical Biology Respiration In Plants Quiz 8 - MCQExams.com

• During fermentation, glucose undergoes glycolysis and yields pyruvic acid, which is then converted to acetyl CoA. 
• Then glyceraldehyde phosphate is produced, which is then converted to acetaldehyde and this acetaldehyde is converted into ethanol.
• It is a two-step process. In the first step pyruvic acid is decarboxylated to yield acetaldehyde and CO2. Pyruvic acid is a 3-C compound and acts as an electron donor while acetaldehyde is the electron acceptor.
  Thus, Triose phosphate is the electron donor, while acetaldehyde is the electron acceptor is the answer.

Solution

Correct answer is option A.

Explanation for correct option:

• Aerobic respiration includes three stages glycolysis, Krebs cycle, and oxidative phosphorylation.
• The glycolysis is a ten-step process in which glucose is converted into the molecule pyruvate.
• The pyruvate is converted into the acetyl-CoA in the intermediate step of cellular respiration.
• In a single turn of the TCA cycle, two carbons enter from acetyl CoA, and two molecules of carbon dioxide are released. 

$$\textbf{Correct answer: A}$$ 

$$\textbf{Option (A):}$$ 

$$\bullet$$ Glycolysis is the first part of cellular respiration which occurs in both aerobic and anaerobic respiration. 

$$\bullet$$ The end product of glycolysis is pyruvate. Pyruvate is oxidized to produce acetyl CoA. 

$$\bullet$$ This acetyl CoA enters the Krebs cycle which occurs in the mitochondrial membrane. So, acetyl CoA acts as the connecting link between the two processes. 

$$\textbf{Option (B):}$$ 

$$\bullet$$ Oxaloacetic acid is a residue which is part of the Krebs cycle and it is not the connecting link. 

$$\textbf{Option (C):}$$ 

$$\bullet$$ Pyruvic acid is the end product of glycolysis and it needs to be oxidized.

$$\bullet$$ Pyruvate is not able to enter the Krebs cycle directly. 

$$\textbf{Option (D):}$$ 

$$\bullet$$ Citrate is one of the intermediates in the Krebs cycle.

Hence, the correct answer is option (A).

$$\textbf{Correct Option C}$$

$$\textbf{Solution}$$

$$\bullet$$ $$\textbf{Option A}$$ Option A. When the phosphate bond of creatine phosphate is hydrolyzed is a yield of high free energy. The reason for this high free energy is the difference between the free energies of the reactants and the products.

$$\bullet$$ $$\textbf{Option B}$$ ADP is hydrolyzed the free energy released during the reaction is around a range of 7.3 Kcal/mol.

$$\bullet$$ $$\textbf{Option C}$$ During the hydrolysis of glucose 6 phosphate the yield of free energy have a negative value which is around -3.3 Kcal/mol.

$$\bullet$$ $$\textbf{Option D}$$ Reaction of hydrolysis of the phosphate found in ATP the range of the free energy released is 7.3 Kcal/mol.

So, the correct option is C. 

• Fermentation is anaerobic respiration that does not require oxygen for the breakdown and transformation of organic nutrients. 
• Fermentation is controlled by enzymes. 
• The common product of fermentation are ethanol, CO$$_2$$, and lactic acid.
• Some amount of energy is also produced in the process of fermentation.

• Glycolysis and fermentation take place in the cytoplasm of a cell.
• The Krebs cycle occurs in the mitochondrial matrix during aerobic respiration followed by an electron transport chain whose component proteins are located in the inner mitochondrial membrane, not in the mitochondrial matrix.
• Photosynthesis requires the presence of chlorophyll pigment that is present within the chloroplast.