Carbohydrate Metabolism: Glycolysis and Gluconeogenesis

These flashcards cover key concepts related to carbohydrate metabolism, particularly glycolysis and gluconeogenesis, including processes, reactions, and regulatory mechanisms.

What is the primary pathway for glucose metabolism?

Glycolysis

What happens to glucose in the investment phase of glycolysis?

Two ATP molecules are used to initiate glycolysis.

What is the major energy product of glycolysis?

ATP

Which enzyme catalyzes the first step of glycolysis?

Hexokinase

What is produced at the end of glycolysis?

Pyruvate

What does the enzyme PFK-1 do in glycolysis?

It phosphorylates Fructose 6-phosphate to Fructose 1,6-bisphosphate.

What is the role of lactate dehydrogenase in anaerobic glycolysis?

It reduces pyruvate to lactate.

What is produced during the payoff phase of glycolysis?

2 ATP and 2 NADH.

What type of reaction is the conversion of glucose 6-phosphate to fructose 6-phosphate?

Isomerization.

What is the final product of glycolysis that enters the Krebs cycle?

Acetyl CoA.

What does the enzyme pyruvate kinase do?

It transfers a phosphate from PEP to ADP to form ATP.

What is gluconeogenesis?

The synthesis of glucose from non-carbohydrate precursors.

Where does gluconeogenesis primarily occur?

In the liver and to a limited extent in the kidney.

What cofactor is used in the conversion of pyruvate to oxaloacetate in gluconeogenesis?

Biotin.

What is the Cori Cycle?

The process of glucose transport to working tissues and lactate transport back to the liver.

What key enzyme is used to convert fructose 1,6-bisphosphate to fructose 6-phosphate in gluconeogenesis?

Fructose 1,6-bisphosphatase (FBPase-1).

What is the effect of insulin on glycolysis?

Insulin activates glycolysis by promoting the activity of hexokinase, PFK-1, and pyruvate kinase.

What are GLUT transporters?

A family of glucose transporters that mediate glucose uptake into cells.

What happens to glucose during the digestion process?

It is broken down into monosaccharides and absorbed into the bloodstream.

What is the difference between aerobic and anaerobic glycolysis?

Aerobic glycolysis requires oxygen, while anaerobic glycolysis occurs in the absence of oxygen.

How is the energy released in glycolysis?

Through the conversion of glucose to pyruvate, producing ATP.

What is the role of NAD+ in glycolysis?

It acts as an electron acceptor and is converted to NADH.

What is an aldolase in glycolysis?

An enzyme that catalyzes the cleavage of fructose 1,6-bisphosphate.

How many steps are in the glycolytic pathway?

Ten steps.

What type of process is glycolysis?

A catabolic process.

What happens to pyruvate when oxygen is present?

It is converted to Acetyl CoA for entry into the Krebs cycle.

What are the two conformational states of GLUT transporters?

Conformational state 1 (binding glucose) and conformational state 2 (transporting glucose).

What energy currency is produced during glycolysis?

ATP.

What triggers the translocation of GLUT4 to the cell surface?

Insulin.

What is the result of pyruvate conversion during intense exercise?

It is converted to lactate due to anaerobic conditions.

What are triacylglycerols used for in gluconeogenesis?

As a source of fatty acids for glucose synthesis.

How is fructose 1,6-bisphosphate regulated?

It is inhibited by fructose 2,6-bisphosphate.

What is significant about step 10 of glycolysis?

It is an irreversible reaction resulting in the formation of pyruvate.