Kreb's Cycle Quiz

What is the first molecule formed in the Krebs cycle when acetyl-CoA combines with oxaloacetate?

• Citrate

• Succinate

• Malate

• Isocitrate

Which enzyme catalyzes the conversion of pyruvate to acetyl-CoA?

• Citrate synthase

• Pyruvate dehydrogenase

• Pyruvate carboxylase

• Lactate dehydrogenase

During oxidative phosphorylation, which molecule acts as the final electron acceptor?

• Oxygen

• Carbon dioxide

• NAD+

• FADH2

What is the main purpose of the Krebs cycle?

• To produce ATP directly

• To generate electron carriers for the electron transport chain

• To convert glucose to pyruvate

• To produce carbon dioxide as a waste product

Which compound is NOT a product of the Krebs cycle?

• ATP

• NADH

• FADH2

• O2

In which part of the mitochondrion does the Krebs cycle occur?

• Outer membrane

• Inner membrane

• Matrix

• Intermembrane space

How many molecules of CO2 are produced per acetyl-CoA molecule entering the Krebs cycle?

• One

• Two

• Three

• Four

Which enzyme in the Krebs cycle catalyzes the substrate-level phosphorylation of GDP to GTP?

• Succinate dehydrogenase

• Succinyl-CoA synthetase

• Malate dehydrogenase

• Aconitase

What is the role of NAD+ in the Krebs cycle?

• It acts as an electron donor

• It acts as an electron acceptor

• It directly synthesizes ATP

• It converts GTP to ATP

Which molecule is regenerated at the end of the Krebs cycle to enter another cycle?

• Acetyl-CoA

• Citrate

• Oxaloacetate

• Pyruvate