All Free Biology MCQs with Answers

4151. Glycolysis is process found in:

• A. Most body cells
• B. Eukaryotic cells
• C. Anaerobic bacteria
• D. Virtually all cells

Explanation: "The explanation for this question will be added soon!"

4152. How many molecules of oxygen gas are used in the glycolysis of one glucose molecule?

• A. 1
• B. 16
• C. 38
• D. 0

Explanation: "The explanation for this question will be added soon!"

4153. Krebs Cycle starts with the formation of a 6-carbon atom compound by a chemical reaction between:

• A. Succinic Acid and Acetyl-CoA
• B. Fumaric Acid and Pyruvic Acid
• C. Oxaloacetic Acid and Acetyl-CoA
• D. Malic Acid and Acetyl-CoA

Explanation: Krebs cycle starts with the formation of a six-carbon compound by the reaction between oxaloacetic acid and acetyl CoA. The 6-carbon compound formed is citric acid and this reaction is catalyzed by citrate synthase.

4154. Most of the energy in the cell is liberated by oxidation of carbohydrates when:

• A. Glucose is converted into alcohol and CO2
• B. Sugar is converted into pyruvic acid
• C. Pyruvic acid is converted into CO2 and H2O
• D. Pyruvic acid is converted into CoA

Explanation: "The explanation for this question will be added soon!"

4155. Pyruvate dehydrogenase is used in converting:

• A. Glucose to pyruvate
• B. Pyruvic acid to lactic acid
• C. Pyruvate to acetyl-CoA
• D. Pyruvate to glucose

Explanation: "The explanation for this question will be added soon!"

4156. How many carbon atoms are in an oxaloacetic acid molecule, which joins with an acetyl group during step 1 of the Krebs cycle?

• A. 6
• B. 5
• C. 4
• D. 2

Explanation: "The explanation for this question will be added soon!"

4157. Synthesis of ATP in mitochondria takes place:

• A. In the matrix
• B. At the cristae
• C. At the outer membrane
• D. In the intra cristae space

Explanation: "The explanation for this question will be added soon!"

4158. In the Krebs cycle, the hydrogen atoms removed at the succinate level are accepted by:

• A. FAD
• B. ADP
• C. ATP
• D. NAD

Explanation: "The explanation for this question will be added soon!"

4159. A molecule of FADH2

• A. Consumes one O2
• B. Consumes one H2O molecule
• C. Forms 2 ATP
• D. All the above

Explanation: "The explanation for this question will be added soon!"

4160. Pyruvate is broken down to_ in yeast.

• A. Acetyl CoA
• B. Alcohol
• C. Lactic acid
• D. All of these

Explanation: "The explanation for this question will be added soon!"This is correct because in yeast alcoholic fermentation takes place and the pyruvic acid after decarboxylation is converted into acetaldehyde which is further reduced to alcohol(ethanol)