Glycolysis and PPP Quiz

Which form of glycolysis is primarily used by proliferating or cancerous cells

• Aerobic glycolysis

• Anaerobic glycolysis

• Gluconeogenesis

• Oxidative phosphorylation

Why is the second phase of glycolysis referred to as the "payoff stage"?

• It generates ATP and NADH through the breakdown of pyruvate.

• It consumes ATP to break glucose into smaller molecules.

• It produces ATP and NADH by oxidizing glyceraldehyde-3-phosphate (GAP)

• It uses lactate to regenerate ATP in anaerobic conditions.

The NAD⁺/NADH ratio in mammalian cells is approximately 1000. What does this suggest about the cytoplasmic environment?

• It is favorable for reduction reactions.

• It is favorable for oxidation reactions.

• It is favorable for ATP hydrolysis.

• It is unfavorable for glycolysis.

Which of the following enzymes is used to help replenishing NAD⁺ in the cell?

• Pyruvate kinase

• Hexokinase

• Lactate dehydrogenase

• Succinate dehydrogenase

How is acidification from anaerobic glycolysis combated in cells?

• By accumulating protons to lower the intracellular pH further

• By inhibiting glycolysis to prevent further acid production

• By increasing ATP production through oxidative phosphorylation

• By the bicarbonate (HCO₃⁻) buffer system neutralizing excess protons

Which of the following are stimulators of PFK-1 (phosphofructokinase-1) in glycolysis?

• ATP and citrate

• Fructose-2,6-bisphosphate and AMP

• NADH and glucose-6-phosphate

• Acetyl-CoA and pyruvate

Why is the first step in glycolysis, catalyzed by hexokinase, considered irreversible?

• It consumes ATP, making the reaction highly exergonic and unidirectional.

• It produces pyruvate, which cannot be converted back into glucose.

• It occurs in the mitochondria, where reverse reactions are not possible.

• It depends on oxygen availability, preventing reversibility under anaerobic conditions.

What effect does an increase in blood glucose have on hexokinase in red blood cells?

• It decreases the activity of hexokinase to prevent excessive glucose consumption.

• It largely increases the activity of hexokinase to promote more glycolysis.

• It has little effect on hexokinase activity because it’s always saturated.

• It inhibits hexokinase to prevent glucose-6-phosphate accumulation.

Which liver metabolite up regulates the activity of PFK-1 (phosphofructokinase-1)?

• Glucose-6-phosphate

• Pyruvate

• Acetyl-CoA

• Fructose-2,6-bisphosphate

What is the primary function of the pentose phosphate pathway (PPP)?

• To produce ATP through oxidative phosphorylation

• To generate NADPH and ribose-5-phosphate for biosynthetic reactions

• To break down glucose into lactate for energy production

• To convert pyruvate into glucose through gluconeogenesis