Carbohydrate Metabolism Quizzes: Test Your Understanding

Question 1

In glycolysis, which enzyme catalyzes the irreversible conversion of fructose-6-phosphate to fructose-1,6-bisphosphate?

Accepted Answer

Phosphofructokinase-1

Answer

Hexokinase

Answer

Glyceraldehyde-3-phosphate dehydrogenase

Answer

Pyruvate kinase

Question 2

Which of the following enzymes catalyzes the rate-limiting step of glycolysis?

Accepted Answer

Phosphofructokinase 1

Answer

Hexokinase

Answer

Glyceraldehyde-3-phosphate dehydrogenase

Answer

Pyruvate kinase

Question 3

What is the primary metabolic fate of pyruvate under aerobic conditions?

Accepted Answer

Entry into the citric acid cycle

Answer

Conversion to lactate

Answer

Conversion to ethanol

Answer

Entry into the pentose phosphate pathway

Question 4

Which hormone primarily stimulates gluconeogenesis?

Accepted Answer

Glucagon

Answer

Insulin

Answer

Cortisol

Answer

Adrenaline

Question 5

What is the primary role of glycogen phosphorylase in glycogen metabolism?

Accepted Answer

Glycogen breakdown

Answer

Glycogen synthesis

Answer

Glycogen branching

Answer

Glycogen debranching

Question 6

Which pathway generates NADPH for reductive biosynthesis?

Accepted Answer

Pentose phosphate pathway

Answer

Glycolysis

Answer

Gluconeogenesis

Answer

Citric acid cycle

Question 7

What is the major end product of anaerobic glycolysis in skeletal muscle?

Accepted Answer

Lactate

Answer

Pyruvate

Answer

Acetyl-CoA

Answer

Glucose-6-phosphate

Question 8

Which metabolic disorder results from a genetic deficiency of glucose-6-phosphate dehydrogenase?

Accepted Answer

Favism

Answer

Type I diabetes

Answer

Type II diabetes

Answer

Glycogen storage disease

Question 9

What is the substrate for fructose-1,6-bisphosphatase in gluconeogenesis?

Accepted Answer

Fructose-1,6-bisphosphate

Answer

Glucose

Answer

Glucose-6-phosphate

Answer

Fructose-6-phosphate

Question 10

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

Accepted Answer

Phosphoglycerate mutase

Answer

Phosphoglycerokinase

Answer

Enolase

Answer

Pyruvate kinase

Question 11

What is the primary function of insulin in carbohydrate metabolism?

Accepted Answer

Promoting glucose uptake into cells

Answer

Inhibiting glucose uptake into cells

Answer

Stimulating glycogen breakdown

Answer

Inhibiting glycogen synthesis

Question 12

What is the primary purpose of gluconeogenesis in the body?

Accepted Answer

To generate glucose from non-carbohydrate sources during fasting

Answer

To break down glucose for energy

Answer

To convert glucose into glycogen

Answer

To produce pentose sugars

Question 13

What is the initial step of the pentose phosphate pathway, leading to the production of ribose-5-phosphate?

Accepted Answer

Glucose-6-phosphate oxidation

Answer

Ribose-5-phosphate formation

Answer

NADPH production

Answer

Glucuronic acid synthesis

Question 14

Which of the following is NOT a product generated in the citric acid cycle?

Accepted Answer

Glyceraldehyde-3-phosphate

Answer

ATP

Answer

NADH

Answer

FADH2

Question 15

What molecule serves as the primary energy currency within cells, providing immediate energy for cellular processes?

Accepted Answer

ATP

Answer

Glucose

Answer

NADH

Answer

Pyruvate

Question 16

Which enzyme is involved in both glycolysis and gluconeogenesis, playing a key role in the interconversion of glucose and other intermediates?

Accepted Answer

Glyceraldehyde-3-phosphate dehydrogenase

Answer

Hexokinase

Answer

Phosphofructokinase

Answer

Pyruvate kinase

Question 17

Under which condition does the body shift carbohydrate metabolism towards anaerobic pathways, resulting in the production of lactic acid as a byproduct?

Accepted Answer

Hypoxia (low oxygen availability)

Answer

Hyperglycemia (high blood glucose)

Answer

Glucagon deficiency

Answer

Insulin resistance

Question 18

Which of the following is the final product of glycolysis in the absence of oxygen?

Accepted Answer

Lactate

Answer

Acetyl-CoA

Answer

Pyruvate

Answer

Glucose-6-phosphate

Question 19

Which of the following hormones stimulates glycogen synthesis?

Accepted Answer

Insulin

Answer

Cortisol

Answer

Somatostatin

Answer

Glucagon

Question 20

What is the primary function of the pentose phosphate pathway?

Accepted Answer

Generation of NADPH and ribose-5-phosphate for nucleotide and nucleic acid synthesis

Answer

Breakdown of fatty acids

Answer

Production of ATP

Answer

Synthesis of glucose

Question 21

Which of the following is a substrate for the pentose phosphate pathway?

Accepted Answer

Glucose-6-phosphate

Answer

Acetyl-CoA

Answer

Glycerol

Answer

Amino acids

Question 22

Which of the following metabolic pathways produces the most ATP per glucose molecule metabolized?

Accepted Answer

Oxidative phosphorylation

Answer

Substrate-level phosphorylation

Answer

Glycolysis

Question 23

What is the significance of the Cori cycle?

Accepted Answer

It allows lactate produced in muscle to be converted into glucose in the liver, maintaining blood glucose levels.

Answer

It is involved in the synthesis of amino acids.

Answer

It generates ATP through substrate-level phosphorylation.

Question 24

Which of the following is a characteristic feature of type 1 diabetes mellitus?

Accepted Answer

Absolute deficiency of insulin

Answer

Insulin resistance

Answer

Reduced glycogen synthesis

Answer

Impaired glucagon secretion

Question 25

What is the main site of glycogen synthesis and storage in the body?

Accepted Answer

Liver

Answer

Pancreas

Answer

Adipose tissue

Answer

Muscle