Q: Which of the following equations correctly represents the overall reaction of glycolysis?

$$\text{Glucose} + 2 \text{NAD}^+ + 2 \text{ADP} + 2 \text{P}_i \rightarrow 2 \text{pyruvate} + 2 \text{NADH} + 2 \text{H}^+ + 2 \text{ATP} + 2 \text{H}_2\text{O}$$

Question 1

Which of the following is NOT a major destiny of glucose in cellular metabolism?

Accepted Answer

Conversion to fatty acids for long-term energy storage

Question 2

During glycolysis, which step is considered the first committed and irreversible step?

Accepted Answer

Phosphorylation of fructose 6-phosphate to fructose 1,6-bisphosphate by phosphofructokinase-1

Question 3

What is the net ATP yield from one molecule of glucose during glycolysis?

Accepted Answer

$$2$$

Question 4

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

Accepted Answer

Triose phosphate isomerase

Question 5

Why are all glycolytic intermediates phosphorylated?

Accepted Answer

To prevent their diffusion out of the cell and facilitate enzymatic energy conservation

Question 6

Which of the following best describes the role of NAD+ in glycolysis?

Accepted Answer

It is reduced to NADH during the oxidation of glyceraldehyde 3-phosphate

Question 7

Under anaerobic conditions in muscle cells, pyruvate is converted to which product, and what is the purpose of this conversion?

Accepted Answer

Lactate, to regenerate NAD+

Question 8

Which of the following equations correctly represents the overall reaction of glycolysis?

Accepted Answer

$$	ext{Glucose} + 2 	ext{NAD}^+ + 2 	ext{ADP} + 2 	ext{P}_i ightarrow 2 	ext{pyruvate} + 2 	ext{NADH} + 2 	ext{H}^+ + 2 	ext{ATP} + 2 	ext{H}_2	ext{O}$$

Question 9

Which glycolytic enzyme is negatively regulated by ATP, and why is this regulation important?

Accepted Answer

Phosphofructokinase-1; to prevent unnecessary glucose breakdown when energy is abundant

Question 10

In gluconeogenesis, which enzyme catalyzes the conversion of pyruvate to oxaloacetate, and what cofactor does it require?

Accepted Answer

Pyruvate carboxylase; biotin

Question 11

Which of the following statements about the preparatory phase of glycolysis is TRUE?

Accepted Answer

It requires the investment of two ATP molecules

Question 12

Which step in glycolysis is responsible for the first substrate-level phosphorylation, and what is the product?

Accepted Answer

Phosphoglycerate kinase; ATP

Question 13

Which of the following is a reason why fatty acids cannot be converted to glucose in humans?

Accepted Answer

Fatty acids are degraded to acetyl-CoA, which cannot serve as a precursor for gluconeogenesis

Question 14

Which enzyme in gluconeogenesis catalyzes the hydrolysis of fructose 1,6-bisphosphate, and what is the effect of AMP on this enzyme?

Accepted Answer

Fructose 1,6-bisphosphatase; AMP inhibits its activity

Question 15

Which of the following best explains the Warburg effect observed in cancer cells?

Accepted Answer

Cancer cells rely heavily on glycolysis for energy due to limited oxygen and fewer mitochondria

Question 16

What is the free energy change ($$\Delta G) $$for the overall glycolytic reaction under standard conditions?

Accepted Answer

$$-85 kJ/$$mol

Question 17

Which of the following is a glucogenic amino acid that can serve as a precursor for glucose synthesis?

Accepted Answer

Alanine

Question 18

Which enzyme catalyzes the conversion of 3-phosphoglycerate to 2-phosphoglycerate in glycolysis?

Accepted Answer

Phosphoglycerate mutase

Question 19

Which glycolytic intermediate is the substrate for the enzyme enolase?

Accepted Answer

2-phosphoglycerate

Question 20

Which of the following statements about gluconeogenesis is CORRECT?

Accepted Answer

It requires six high-energy phosphodiester bonds and two NADH per glucose synthesized

Glycolysis and Gluconeogenesis: Pathways of Glucose Metabolism

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