Question 1

According to the second law of thermodynamics, which of the following statements is correct regarding entropy in biological systems?

Accepted Answer

Entropy of the universe always increases, although local decreases in entropy can occur in cells.

Question 2

Which molecule acts as an electron carrier by accepting electrons during glycolysis, and what is its reduced form?

Accepted Answer

NAD$$^+$$; NADH

Question 3

During glycolysis, which step involves substrate-level phosphorylation resulting in the direct formation of ATP?

Accepted Answer

Conversion of phosphoenolpyruvate (PEP) to pyruvate

Question 4

Which of the following best describes the net products of glycolysis from one molecule of glucose?

Accepted Answer

2 pyruvate, 2 NADH, and 2 ATP

Question 5

Alcohol fermentation in yeast results in the production of which two main products?

Accepted Answer

Ethanol and CO$$_2$$

Question 6

Which enzyme catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate in glycolysis?

Accepted Answer

Phosphofructokinase (PFK)

Question 7

In glycolysis, which step is considered the rate-limiting step and is subject to allosteric regulation by ATP?

Accepted Answer

Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate

Question 8

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

Accepted Answer

$$ \mathrm{Glucose} + 2\ \mathrm{NAD}^+ + 2\ \mathrm{ADP} + 2\ \mathrm{P_i} \rightarrow 2\ \mathrm{Pyruvate} + 2\ \mathrm{NADH} + 2\ \mathrm{ATP} + 2\ \mathrm{H_2O} $$

Question 9

Which process allows cells to regenerate NAD$$^+$$ under anaerobic conditions, enabling glycolysis to continue?

Accepted Answer

Alcohol fermentation

Question 10

A patient with a genetic deficiency in lactate dehydrogenase would have difficulty performing which metabolic process?

Accepted Answer

Lactic acid fermentation

Question 11

Which of the following best explains why ATP hydrolysis is often coupled to energetically unfavorable reactions in cells?

Accepted Answer

ATP hydrolysis releases free energy ($$ \Delta G ) $$that can drive non-spontaneous reactions.

Question 12

During glycolysis, which intermediate is split into two three-carbon molecules?

Accepted Answer

Fructose-1,6-bisphosphate

Question 13

Which enzyme is responsible for the final step of glycolysis, converting phosphoenolpyruvate (PEP) to pyruvate?

Accepted Answer

Pyruvate kinase

Question 14

If a cell is exposed to a toxin that inhibits phosphofructokinase (PFK), which of the following would most likely occur?

Accepted Answer

Glycolysis would slow down or stop, reducing ATP production.

Question 15

Which of the following statements about substrate-level phosphorylation is correct?

Accepted Answer

It involves the direct transfer of a phosphate group to ADP to form ATP.

Question 16

In a muscle cell undergoing intense exercise, which pathway is most likely to be activated to regenerate NAD$$^+$$?

Accepted Answer

Lactic acid fermentation

Question 17

Which of the following is a key difference between catabolism and anabolism?

Accepted Answer

Catabolism releases energy by breaking down molecules, while anabolism consumes energy to build molecules.

Question 18

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

Accepted Answer

It accepts electrons during the oxidation of glyceraldehyde-3-phosphate.

Question 19

A baker is making bread and relies on yeast fermentation. Which metabolic process is responsible for the rising of the dough?

Accepted Answer

Release of CO$$_2$$ during alcohol fermentation

Question 20

Which of the following is true regarding the regulation of glycolysis by ATP?

Accepted Answer

High levels of ATP inhibit phosphofructokinase, slowing glycolysis.

Chemotropic Energy Metabolism: Glycolysis and Fermentation – Study Notes

Study Guide - Practice Questions

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