Question 1

Which of the following best describes the main function of glycolysis in cellular metabolism?

Accepted Answer

To split glucose into two molecules of pyruvic acid, producing ATP and NADH

Question 2

What determines whether pyruvic acid produced in glycolysis will enter the citric acid cycle or be converted to lactic acid?

Accepted Answer

The presence or absence of oxygen

Question 3

Which of the following is a correct summary of the net products of glycolysis from one molecule of glucose?

Accepted Answer

$$2$$ pyruvic acid, $$2$$ NADH, $$2$$ ATP

Question 4

Why is lactic acid fermentation not favored by the body for long-term ATP production?

Accepted Answer

It yields very little ATP and can lead to cellular acidity

Question 5

Which enzyme is responsible for converting lactic acid back to pyruvic acid in the liver?

Accepted Answer

Lactic acid dehydrogenase

Question 6

What is the main purpose of the transition step between glycolysis and the citric acid cycle?

Accepted Answer

To convert pyruvic acid into acetyl CoA and release $$CO_2$$

Question 7

Where does the citric acid (Krebs) cycle occur within the cell?

Accepted Answer

Mitochondrial matrix

Question 8

Which of the following best describes the role of oxygen in the electron transport chain?

Accepted Answer

It is the final electron acceptor, forming water

Question 9

If a cell produces $$2$$ NADH molecules during metabolism, how many ATP are theoretically generated from these NADH in the electron transport chain?

Accepted Answer

$$6$$ ATP

Question 10

Why can only the liver release glucose into the bloodstream after glycogenolysis?

Accepted Answer

Only the liver contains the enzyme glucose 6-phosphatase

Question 11

Which process describes the formation of glucose from non-carbohydrate sources such as amino acids or lactic acid?

Accepted Answer

Gluconeogenesis

Question 12

What is the main function of the Cori cycle?

Accepted Answer

To convert lactic acid produced in muscles into glucose in the liver

Question 13

Which of the following is a correct equation for the complete aerobic oxidation of glucose?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP$$

Question 14

Which of the following statements about lipogenesis is correct?

Accepted Answer

It is the synthesis of triglycerides from acetyl CoA and glycerol

Question 15

During prolonged fasting or uncontrolled diabetes, which process leads to the accumulation of ketone bodies in the blood?

Accepted Answer

Ketogenesis

Question 16

Which of the following is NOT a product of the citric acid (Krebs) cycle?

Accepted Answer

Glucose

Question 17

What is the theoretical maximum number of ATP molecules produced from the complete oxidation of one molecule of glucose?

Accepted Answer

$$36-38$$

Question 18

Which of the following best describes the process of beta-oxidation?

Accepted Answer

The removal of two-carbon units from fatty acids to form acetyl CoA

Question 19

Which coenzymes are reduced during the citric acid cycle and later used in the electron transport chain?

Accepted Answer

NAD and FAD

Question 20

Which of the following is a reason why glucose cannot be stored as free glucose in cells?

Accepted Answer

Glucose attracts water, causing cells to swell and lyse

Respiration and Metabolism: Biochemical Pathways in Human Physiology

Study Guide - Practice Questions