5 Metabolism and Energy Use Free Online FlashCards

How do catabolism and anabolism differ?

Catabolism breaks molecules down and captures some of their energy; anabolism uses energy and small molecules to build and maintain tissues.

What is ATP’s role in cellular energy use?

ATP is the cell’s immediately usable energy currency. Nutrient energy is transferred mainly to ATP and electron carriers such as NADH and FADH₂.

What happens during glycolysis?

Glycolysis occurs in the cytosol and splits glucose into two pyruvate molecules, producing a small amount of ATP and NADH.

What is glycolysis’s net ATP yield, and when can lactate form?

Glycolysis yields a net of two ATP per glucose. When oxygen-dependent metabolism cannot keep pace with demand, pyruvate can be converted to lactate so glycolysis can continue producing ATP.

What does pyruvate oxidation produce?

When conditions permit, pyruvate enters mitochondria and is converted to acetyl-CoA, producing NADH and carbon dioxide.

What does the citric acid cycle generate?

In the mitochondrial matrix, acetyl-CoA is oxidized, releasing carbon dioxide and generating NADH, FADH₂, and a small amount of ATP-equivalent energy.

How does oxidative phosphorylation use electrons to make ATP?

NADH and FADH₂ deliver electrons to the chain on the inner mitochondrial membrane. The resulting proton gradient drives ATP synthesis; oxygen accepts electrons at the end, forming water.

About how much ATP comes from complete oxidation of one glucose?

Complete oxidation of one glucose molecule yields roughly 30–32 ATP, though the exact total varies with cellular conditions.

How do glycogenesis and glycogenolysis differ?

Glycogenesis builds glycogen, while glycogenolysis breaks it down. Liver glycogen can support blood glucose; muscle glycogen is mainly used by muscle itself.

What is gluconeogenesis, and which precursors can support it?

Gluconeogenesis makes glucose from precursors such as lactate, glycerol, and certain amino acids, especially when glycogen availability is limited.

How do lipolysis and beta-oxidation process stored fat?

Lipolysis splits triglycerides into fatty acids and glycerol. Beta-oxidation breaks fatty acids into two-carbon units that form acetyl-CoA, while generating NADH and FADH₂.

When does the liver make ketone bodies, and how are they used?

During prolonged fasting or very low carbohydrate availability, the liver can convert some acetyl-CoA into ketone bodies. Other tissues can use them as fuel, and the brain increases its use during prolonged fasting.