Question 1

Which of the following is NOT a major fate of glucose in animal cells?

Accepted Answer

Conversion to fatty acids via beta-oxidation

Question 2

What is the net ATP yield from glycolysis per molecule of glucose under aerobic conditions?

Accepted Answer

$$2$$ ATP

Question 3

Which enzyme catalyzes the first committed step of glycolysis, and why is this step considered 'committed'?

Accepted Answer

Phosphofructokinase-1 (PFK-1); because it irreversibly commits glucose to glycolysis

Question 4

In the preparatory phase of glycolysis, how many ATP molecules are consumed per molecule of glucose?

Accepted Answer

$$2$$ ATP

Question 5

Which glycolytic intermediate is the substrate for the first ATP-generating (substrate-level phosphorylation) step?

Accepted Answer

1,3-Bisphosphoglycerate

Question 6

A patient is injected with $$^{18}F-$$fluoro-2-deoxyglucose for a PET scan. Which glycolytic enzyme is responsible for trapping this molecule inside cells?

Accepted Answer

Hexokinase

Question 7

Which of the following statements about the aldolase reaction in glycolysis is TRUE?

Accepted Answer

It is reversible and the direction depends on the concentrations of substrates and products

Question 8

What is the overall chemical equation for glycolysis, starting from glucose and ending with pyruvate?

Accepted Answer

$$\mathrm{Glucose} + 2 \mathrm{NAD}^+ + 2 \mathrm{ADP} + 2 \mathrm{P_i} \rightarrow 2 \mathrm{Pyruvate} + 2 \mathrm{NADH} + 2 \mathrm{ATP} + 2 \mathrm{H}_2\mathrm{O} + 2 \mathrm{H}^+$$

Question 9

Which glycolytic enzyme is named for the reverse reaction, and what is its role in glycolysis?

Accepted Answer

Phosphoglycerate kinase; it catalyzes substrate-level phosphorylation to generate ATP

Question 10

During glycolysis, which step is responsible for the production of NADH?

Accepted Answer

Conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate

Question 11

Which of the following best explains why glycolysis is essential for cancer cells?

Accepted Answer

It allows rapid ATP production even under low oxygen conditions

Question 12

If a cell is supplied with $$^{14}C-$$labeled glyceraldehyde 3-phosphate, which carbons of fructose 1,6-bisphosphate will be labeled after equilibration?

Accepted Answer

C-3 and C-4

Question 13

Which glycolytic intermediate has the highest standard free energy of hydrolysis, making it an excellent donor for substrate-level phosphorylation?

Accepted Answer

Phosphoenolpyruvate

Question 14

Which enzyme catalyzes the conversion of dihydroxyacetone phosphate (DHAP) to glyceraldehyde 3-phosphate (G3P) in glycolysis?

Accepted Answer

Triose phosphate isomerase

Question 15

Which of the following statements about substrate channeling in glycolysis is CORRECT?

Accepted Answer

It couples sequential reactions, minimizing loss of intermediates and increasing efficiency

Question 16

What is the role of Mg$$^{2+} in $$the hexokinase-catalyzed reaction?

Accepted Answer

It shields the negative charges of ATP, facilitating phosphoryl transfer

Question 17

Which glycolytic enzyme catalyzes the dehydration of 2-phosphoglycerate to phosphoenolpyruvate?

Accepted Answer

Enolase

Question 18

Why is the conversion of phosphoenolpyruvate to pyruvate highly exergonic?

Accepted Answer

Because the enol form of pyruvate tautomerizes to the more stable keto form

Question 19

Which of the following dietary sugars can enter glycolysis after conversion to glucose 6-phosphate?

Accepted Answer

Galactose

Glycolysis and the Fates of Glucose: Biochemistry Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard