Carbohydrate Metabolism: Anabolic Reactions and Cori Cycle

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What is the primary purpose of the Cori cycle?

To promote anaerobic metabolism in the muscles

To convert glucose to lactate in the liver

To prevent lactate accumulation in the muscle

To regenerate glucose from lactate in the liver (correct)

What is the byproduct of anaerobic metabolism in the muscles?

Glycogen

Lactic acid (correct)

Pyruvate

Glucose

What is the significance of the Cori cycle during exercise?

It enables efficient reutilization of lactate (correct)

It promotes gluconeogenesis in the muscles

It increases energy production

It reduces muscle cramps

What happens to lactate in the liver during the Cori cycle?

It is converted to pyruvate (D) Signup and view all the answers

Why is the Cori cycle important during strenuous exercise?

It prevents lactate accumulation in the muscle (D) Signup and view all the answers

What is the net result of the Cori cycle?

Lactate is converted to glucose in the liver (B) Signup and view all the answers

What is the primary organ responsible for replenishing blood glucose through gluconeogenesis?

Liver (B) Signup and view all the answers

What is the primary source of substrates for gluconeogenesis during prolonged starvation?

Protein catabolism (A) Signup and view all the answers

How many ATPs are required to generate one glucose molecule through gluconeogenesis?

6 (D) Signup and view all the answers

What is the effect of glucagon on gluconeogenesis?

It increases gluconeogenesis (A) Signup and view all the answers

What is the primary function of glycogen in the human body?

Storage of carbohydrates (D) Signup and view all the answers

What is the effect of insulin on gluconeogenesis?

It inhibits gluconeogenesis (C) Signup and view all the answers

What is the molecule that is converted into fructose-1-6-bisphosphate?

Glyceraldehyde-3-phosphate (C) Signup and view all the answers

What is the enzyme that converts glucose-6-phosphate into glucose?

Glucose-6-phosphatase (A) Signup and view all the answers

Which enzyme is replaced by glucose-6-phosphatase in gluconeogenesis?

Hexokinase (B) Signup and view all the answers

In which tissue is glucose-6-phosphatase most active?

Liver (D) Signup and view all the answers

What is the initial step in the conversion of oxaloacetate to phosphoenol pyruvate?

Conversion of oxaloacetate to malate by malate dehydrogenase (A) Signup and view all the answers

What is the reaction that is catalyzed by phosphohexo isomerase?

Glucose-6-phosphate to fructose-6-phosphate (A) Signup and view all the answers

What is the purpose of the conversion of oxaloacetate to phosphoenol pyruvate?

To bypass the irreversible step of glycolysis (A) Signup and view all the answers

What is the purpose of replacing certain enzymes in gluconeogenesis?

To regulate glycolysis and gluconeogenesis independently (A) Signup and view all the answers

What is the role of GTP or ATP in the conversion of oxaloacetate to phosphoenol pyruvate?

To donate a phosphate group (A) Signup and view all the answers

What is the net effect of the two reactions involving malate dehydrogenase and PEPCK?

The conversion of pyruvate to phosphoenol pyruvate (A) Signup and view all the answers

What is the subsequent step after the conversion of oxaloacetate to phosphoenol pyruvate?

The conversion of phosphoenol pyruvate to 2-phosphoglycerate (A) Signup and view all the answers

What is the source of the glucose part transferred to a glycogen primer molecule by glycogen synthase?

UDP-glucose (C) Signup and view all the answers

What is the function of glycogenin in glycogen synthesis?

To create the glycogen primer molecule (C) Signup and view all the answers

What is the minimum length of the glycogen chain required for branching enzyme to transfer a block of glucose residues?

11-12 glucose residues (D) Signup and view all the answers

What is the type of bond that connects the glucose residues in a glycogen primer molecule?

Alpha-1,4-glycosidic bond (C) Signup and view all the answers

What is the product of the reaction catalyzed by UDP glucose pyrophosphorylase?

UDP-glucose (A) Signup and view all the answers

What is the function of glycogen synthase in glycogen synthesis?

To add glucose units in alpha-1,4 linkage (A) Signup and view all the answers