Carbohydrate Metabolism

These flashcards cover key concepts and processes related to carbohydrate metabolism, including digestion, glycolysis, gluconeogenesis, glycogenesis, glycogenolysis, and related regulatory mechanisms.

What is the primary function of carbohydrates in the body?

Carbohydrates serve as a primary source of energy for the body.

What are the major processes involved in carbohydrate metabolism?

The major processes are carbohydrate digestion, glycolysis, gluconeogenesis, glycogenesis, and glycogenolysis.

What is the first step of carbohydrate digestion?

Food is masticated in the oral cavity and transformed into a bolus, with salivary amylases beginning starch and glycogen hydrolysis.

Where does the majority of carbohydrate absorption occur?

The majority of carbohydrate absorption occurs in the small intestine.

What is glycolysis?

Glycolysis is the metabolic pathway that converts one molecule of glucose into two molecules of pyruvate, producing ATP and NADH in the process.

What enzyme catalyzes the phosphorylation of glucose to form glucose 6-phosphate?

Hexokinase catalyzes the phosphorylation of glucose.

What is the purpose of gluconeogenesis?

Gluconeogenesis is the metabolic pathway that synthesizes glucose from non-carbohydrate materials.

How many ATP are produced during glycolysis?

A net of 2 ATP molecules are produced for each glucose molecule during glycolysis.

What are the three irreversible steps in glycolysis that are bypassed by gluconeogenesis?

The conversion of pyruvate to PEP, dephosphorylation of fructose 1,6-bisphosphate, and dephosphorylation of glucose 6-phosphate.

What is glycogenesis?

Glycogenesis is the process of converting glucose into glycogen for storage.

What is the role of lactate fermentation in glycolysis?

Lactate fermentation allows glycolysis to continue under anaerobic conditions by converting pyruvate to lactate, regenerating NAD+.

What is the result of ethanol fermentation?

Ethanol fermentation is the conversion of pyruvate into ethanol and carbon dioxide, regenerating NAD+ for glycolysis.

What is glycogenolysis?

Glycogenolysis is the metabolic process of breaking down glycogen into glucose when blood glucose levels are low.

What are the two steps of glycogenolysis?

Phosphorylation of a glucose unit to produce glucose 1-phosphate, followed by isomerization to glucose 6-phosphate.

What regulates glycolysis?

Key regulatory enzymes include hexokinase, phosphofructokinase, and pyruvate kinase, which are allosterically regulated.

What is the fate of pyruvate under aerobic conditions?

Under aerobic conditions, pyruvate is oxidized to acetyl CoA, which then enters the citric acid cycle.