The corresponding yield of ATP from one molecule of ${\mathrm{FADH}}_2$ is:

1.	2	2.	3
3.	4	4.	6

Substrate-level phosphorylation is one of the ways for the formation of ATP. In this process:
1. maximum ATP are produced in higher organisms
2. a high-energy phosphate group is transferred directly to ADP
3. chemiosmosis provides energy for phosphorylation
4. the protein ATP synthase works to add phosphate to ADP

All the following will normally occur during the electron flow in ETS in mitochondria except:
1. NADH and ${\mathrm{FADH}}_2$ are oxidized.
2. the pH of the matrix decreases.
3. the electrons lose free energy.
4. an electrochemical gradient is formed.

The metabolic pathway common to aerobic respiration, anaerobic respiration and fermentation is:
1. chemiosmosis
2. the oxidation of pyruvate to acetyl CoA
3. the citric acid cycle
4. glycolysis

In the fermentation pathway ATP made are generated by:
1. the electron transport chain
2. substrate-level phosphorylation
3. chemiosmosis
4.ATP cannot be formed in this pathway

Fats and proteins can also provide us energy. For this to happen:
1. Fats and proteins must first be converted to glucose
2. Fats and proteins must enter separate catabolic pathways of their own
3. Fats and proteins must be modified to forms that can enter the glucose metabolic pathway
4. Fats must first be converted to proteins that can enter the glucose metabolic pathway

Yeast cells are able to regenerate ${\mathrm{NAD}}^{+}$ regenerated from NADH during the :
1. reduction of acetaldehyde to ethyl alcohol
2. oxidation of pyruvate to acetyl CoA
3. reduction of pyruvate to form lactate
4. oxidation of NAD⁺ in the citric acid cycle

In the glycolytic pathway, ATP formation:
1. does not occur
2. requires presence of oxygen
3. needs a proton gradient across a membrane
4. involves substrate-level phosphorylation

The importance of lactic acid fermentation lies in the fact that it:
1. reduces NAD⁺ to NADH
2. reduces FAD⁺ to FADH₂
3. oxidizes NADH to NAD⁺
4. reduces FADH₂ to FAD⁺

The mitochondrial proton gradient would be highest leading to ATP synthesis when the following condition is present:
1. pyruvate (present)-oxygen (present)-ATP levels (high)
2. pyruvate (present)-oxygen (present)-ATP levels (low)
3. pyruvate (present)-oxygen (absent)-ATP levels (high)
4. pyruvate (absent)-oxygen (present)-ATP levels (low)