Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R): 
 

Assertion (A):	If oxygen is available, it is invariably used as the terminal electron acceptor in aerobic cellular respiration.
Reason (R):	It acts as the terminal electron as well as proton acceptor.

In the light of the above statements choose the correct answer from the options given below:
 

1.	Both (A) and (R) are true and (R) is the correct explanation of (A).
2.	Both (A) and (R) are true but (R) is not the correct explanation of (A).
3.	(A) is true but (R) is false.
4.	Both (A) and (R) are false.

Assertion: Electron transport chains are redox reactions that transfer electrons from an electron donor to an electron acceptor.
Reason: The transfer of electrons is coupled to the translocation of protons across a membrane, producing a proton gradient.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R): 

In the light of the above statements choose the correct answer from the options given below:

Assertion: Cyanide poisoning is a form of histotoxic hypoxia.
Reason: Cyanide binds to iron of cytochrome c oxidase and thus prevents binding of oxygen to hemoglobin.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Homolactic fermentation (producing only lactic acid) is the simplest type of fermentation.
Reason: It is one of the only respiration processes to not produce a gas as a byproduct.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Fermentation is an extension of glycolysis that can generate ATP by substrate level phosphorylation as long as a sufficient supply of NAD⁺ is available.
Reason: NAD⁺ is an oxidizing agent in involved in glycolysis.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Catabolism can also harvest energy stored in fats obtained from food or from storage cells in the body.
Reason: Fatty acids undergo beta oxidation in mitochondria to produce ATP directly.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: All the organic molecules of food are destined to be oxidized as fuel to make ATP.
Reason: The catabolic pathway intermediates cannot be diverted to any anabolic pathway.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: If citrate accumulates in mitochondria, ATP production is slowed down.
Reason: When this happens, some citrate passes into the cytosol and inhibits phosphofructokinase.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: When a glucose fed yeast is transferred from aerobic to anaerobic medium its rate of glucose consumption decreases.
Reason: It starts metabolizing lactose and stops using glucose in anaerobic conditions.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion.
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.