All Free Biology MCQs with Answers

4161. Which of the following is not a process involved in respiration?

• A. Breakdown of glucose
• B. Formation of glucose
• C. Release of energy
• D. Exchange of gases

Explanation: "The explanation for this question will be added soon!"Glucogensis, gluconeogenesis or the formation of glucose ia process which isnot involved in respiration. Hence this option is correct

4162. The role of oxygen in respiration is:

• A. It combines with acetyl-CoA at the start of the Krebs cycle
• B. It plays no role
• C. It is given off as a by-product during the oxidation of pyruvates
• D. It is the final electron acceptor at the end of the electron transport chain

Explanation: "The explanation for this question will be added soon!"In the electron transport chain , oxygen acts as the final electron acceptor and accepts electron and then reacts with 2H+ ions and forms water.

4163. Cytochrome a is oxidized by which of the following in ETC?

• A. Carbon dioxide
• B. Oxygen
• C. ATP
• D. Cytochrome a3

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

4164. What is formed at the end of the preparatory phase of glycolysis?

• A. G3P
• B. Dihydroxyacetone phosphate
• C. Pyruvate
• D. Both A and B

Explanation: The last step in preparatory phase of glycolysis is the enzymatic splitting of fructose 1,6 -bisphosphate into two fragments. Each of these molecules contains three carbon atoms. One is called 3-phospoglyceraldehyde, 3-PGAL or Glyceraldehyde 3-phosphate (G3P) while the other is dihydroxyacetone phosphate. These two molecules are isomers and in fact, are readily interconverted by yet another enzyme of glycolysis.

4165. Hans Krebs discovered in_:

• A. Glycolysis
• B. Fermentation
• C. Pyruvate oxidation
• D. Citric acid cycle

Explanation: This cycle was discovered by British scientist Sir Hans Krebs, therefore, called Krebs cycle. It is also called Citric acid cycle or Tri carboxylic acid (TCA) cycle because the first compound which is formed in the cycle is citrate (citric acid) that contains three carboxylic acid groups.

4166. Light reaction takes place in/on:

• A. Chloroplast
• B. Stroma
• C. Thylakoids
• D. Grana

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

4167. Calvin cycle is:

• A. Inhibited by light
• B. Supported by light
• C. Independent of light
• D. Dependent upon light

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

4168. All possible means of controlling terrorism _ tried to check it.

• A. Have been
• B. Was
• C. Is
• D. Has been

Explanation: The subject of the sentence is "All possible means", which is a plural noun phrase.- The verb "have been" agrees with the plural subject and indicates that various means have been tried in the past.- The phrase "tried to check it" indicates that all possible means were attempted to control terrorism.

4169. Choose the correct one.

• A. Little money he had saved for a rainy day was not sufficient.
• B. A little money he had saved for a rainy day was not sufficient.
• C. Only little money he had saved for a rainy day was not sufficient.
• D. The little money he had saved for a rainy day was not sufficient.

Explanation: It specifies that the small amount of money he had saved for a rainy day was not enough.

4170. Choose the correct option.

• A. Your, her and mine home are situated on the best street of the area.
• B. Yours, my and hers home are situated in the best street of the area.
• C. Your, her, and my home are situated on the best street of the area.
• D. Her, your's, and my home are situated in the best street of the area.

Explanation: "Your," "her," and "my" are all possessive adjectives that correctly modify the noun "home."