Chapter 14: Glucose Utilization and Biosynthesis

These flashcards cover key concepts related to glucose metabolism, glycolysis, gluconeogenesis, and the pentose phosphate pathway, based on the notes from the lecture.

What is the primary function of glucose in metabolism?

Glucose serves as an excellent fuel and a versatile biochemical precursor.

How is glucose stored in the body?

Glucose can be stored in the polymeric form as glycogen or starch.

What are the four major pathways of glucose utilization?

Storage, glycolysis, pentose phosphate pathway, and synthesis of structural polysaccharides.

What is glycolysis?

A sequence of enzyme-catalyzed reactions that converts glucose into pyruvate, capturing some of the oxidation-free energy as ATP and NADH.

What are the feeder pathways for glycolysis?

Glucose, glycogen, and disaccharides like lactose and sucrose that are hydrolyzed into monosaccharides.

What are the main products of glycolysis?

2 pyruvate, 4 ATP (net gain of 2 ATP), and 2 NADH.

What is the Cori cycle?

The cycle wherein lactate produced during anaerobic glycolysis in muscles is transported to the liver and converted back into glucose.

What are the two main types of fermentation?

Lactic acid fermentation and ethanol fermentation.

What role does NAD+ play in glycolysis under anaerobic conditions?

NAD+ is regenerated during fermentation, which allows glycolysis to continue.

What is gluconeogenesis?

The metabolic process by which organisms synthesize glucose from non-carbohydrate precursors.

What are the key enzymes in gluconeogenesis that differ from glycolysis?

Fructose 1,6-bisphosphatase, glucose 6-phosphatase, and pyruvate carboxylase.

What is the pentose phosphate pathway primarily responsible for?

Generating NADPH for reductive biosynthesis and ribose-5-phosphate for nucleotide synthesis.

How does the pentose phosphate pathway relate to glycolysis?

It provides intermediates that can re-enter glycolysis or be used for nucleotide synthesis.

Why is the regulation of glycolysis and gluconeogenesis important?

To prevent a futile cycle and ensure energy is produced only when needed.

What is the significance of phosphofructokinase-1 in glycolysis?

It is a major regulatory enzyme, controlling the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate.

What impact does NADPH have on cellular metabolism?

NADPH acts as an electron donor in biosynthetic reactions and in the repair of oxidative damage.

What are glucogenic amino acids?

Amino acids that can be converted into glucose through gluconeogenesis.

What is the primary role of thiamine pyrophosphate (TPP) in metabolism?

It acts as a cofactor for enzymes such as pyruvate decarboxylase in ethanol fermentation.

In what form does pyruvate contribute to the energy metabolism under aerobic conditions?

Pyruvate enters the citric acid cycle, generating additional ATP and reducing equivalents.