CELS-6-revision2

What is the function of Coenzyme A (CoA) in cellular respiration?

It acts as a carrier for electrons from glycolysis to oxidative phosphorylation

It directly phosphorylates ADP to ATP

It binds to pyruvate to form Acetyl-CoA, entering the Citric Acid Cycle

It donates protons to the Electron Transport Chain

None

During glycolysis, one molecule of glucose is broken down to form how many ATP and NADH molecules?

2 ATP and 2 NADH

4 ATP and 4 NADH

4 ATP and 2 NADH

2 ATP and 4 NADH

None

In the absence of oxygen, how do cells continue to generate ATP?

By using fermentation to regenerate NAD+, allowing glycolysis to continue

By increasing the activity of the Citric Acid Cycle

By redirecting glucose breakdown through oxidative phosphorylation

By directly utilizing NADH and FADH2 as energy sources

None

Oxygen plays a crucial role in oxidative phosphorylation because it __________.

Accepts electrons from NADH before they enter the Electron Transport Chain

Acts as a catalyst for ATP synthase activity

Serves as the final electron acceptor, forming water as a byproduct

Acts as a direct energy source for ATP production

None

During the Citric Acid Cycle, which enzyme catalyzes the reaction where succinate is converted to fumarate while reducing FAD to FADH2?

Isocitrate dehydrogenase, which removes CO2 and transfers electrons to NAD+

Aconitase, which facilitates the rearrangement of citrate into isocitrate

Alpha-ketoglutarate dehydrogenase, responsible for another oxidative decarboxylation step

Succinate dehydrogenase, which directly transfers electrons to FAD and links to the Electron Transport Chain

None

Which of the following statements about the Citric Acid Cycle is true?

It occurs in the cytosol and does not require mitochondria

It produces NADH and FADH2, which transfer electrons to the Electron Transport Chain

It does not produce any high-energy electron carriers

It directly generates the majority of ATP during cellular respiration

None

Which of the following statements about chemiosmosis is false?

It requires a proton gradient across the inner mitochondrial membrane

It occurs in the cytoplasm and does not involve the mitochondrion

It is dependent on ATP synthase to generate ATP

It uses energy from NADH and FADH2 to drive ATP synthesis

None

If the inner mitochondrial membrane were artificially permeabilized to protons, what would be the most immediate consequence?

Glycolysis would stop, as the Electron Transport Chain would no longer function

The Citric Acid Cycle would stop due to the inability to regenerate NAD+

The proton motive force would collapse, preventing ATP production by chemiosmosis

ATP synthase activity would increase due to excess proton flow

None

What is the main reason why ATP is considered a high-energy molecule?

It has a stable phosphate backbone that never breaks down

It has high-energy phosphate bonds that release energy when hydrolyzed

It contains nitrogenous bases that act as energy-storing structures

It releases energy when phosphate bonds are formed

None

10.

The number of mitochondria in a cell varies depending on __________.

The need for protein production rather than energy

The size of the cell rather than its function

The energy demand of the cell

The presence of DNA in the nucleus

None