CATABOLIC PATHWAYS

LONG QUIZ REVIEW

Glycolysis

The metabolic pathway that breaks down glucose into two molecules of pyruvate.

Hexokinase

The enzyme that catalyzes the phosphorylation of glucose to glucose-6-phosphate.

β-oxidation

The process where fatty acids are broken down into acetyl-CoA units.

NADPH

The energy molecule produced in the pentose phosphate pathway and used for biosynthesis.

Lactate Dehydrogenase (LDH)

The enzyme that catalyzes the conversion of pyruvate to lactate.

Transamination

The process where an amino group is transferred from one molecule to another.

Urea

The major nitrogen waste product formed in the liver and excreted by the kidneys.

Acyl-CoA

The activated form of a fatty acid needed before it undergoes β-oxidation.

DHAP and G3P

The two 3-carbon molecules produced when fructose-1,6-bisphosphate is split.

Ketogenesis

The metabolic pathway that generates ketone bodies from acetyl-CoA.

Phosphofructokinase

What enzyme regulates glycolysis by converting F6P to F1,6BP?

Glycerol

enters glycolysis via DHAP?

Urea cycle

Which process produces urea as a method to eliminate nitrogen waste?

Fatty acid transport into mitochondria

What is the function of carnitine in fatty acid metabolism?

Oxaloacetate

compound is NOT a ketone body?

Pyruvate Dehydrogenase

The enzyme that converts pyruvate to acetyl-CoA.

NAD⁺

The coenzyme that is reduced during the conversion of G3P to 1,3-BPG.

Glycerol-Phosphate Shuttle

A shuttle system that transfers electrons from cytosolic NADH to mitochondrial FADH₂.

Carbamoyl Phosphate

The first stable compound formed in the urea cycle.

Glycogenolysis

The metabolic process that converts glycogen to glucose-1-phosphate.

Malate-aspartate shuttle

shuttle yields more ATP per cytosolic NADH?

Pyruvate

What is the glucogenic amino acid product?

Pentose Phosphate Pathway

pathway primarily generates NADPH?

Acetyl-CoA

What is the final product of β-oxidation that enters the TCA cycle?

Pyruvate kinase

Which enzyme in glycolysis catalyzes substrate-level phosphorylation?

2

How many ATP molecules are net gained from one glucose molecule during glycolysis?

Anaerobic

Pyruvate is converted to lactate under which condition?

Pyruvate dehydrogenase

Which enzyme is responsible for converting pyruvate to acetyl-CoA?

DHAP

What molecule enters glycolysis from glycerol breakdown?

15.5–17.5

How many ATP molecules are produced from each molecule of glycerol?

Acetyl-CoA

What compound is produced by β-oxidation from each round of the cycle?

Starvation

What condition leads to ketone body formation?

enzyme arginase

catalyzes the final step of the urea cycle.

Pyruvate kinase

Which enzyme catalyzes the conversion of phosphoenolpyruvate (PEP) to pyruvate?

Malate-aspartate shuttle

Which shuttle system produces 2.5 ATP per cytosolic NADH?

BPG → 3-PG (via phosphoglycerate kinase)

Which glycolysis step produces the first molecule of ATP?

Acetoacetate, β-hydroxybutyrate, acetone

What are the three main ketone bodies?

Phosphofructokinase

enzymes is key to regulating glycolysis?

Glucose-6-phosphate

Which molecule is the starting point of the Pentose Phosphate Pathway?

Thiamine pyrophosphate (TPP)

Which vitamin-derived cofactor is required by pyruvate decarboxylase?

Carbamoyl phosphate and ornithine

In the urea cycle, citrulline is formed from which two compounds?

Enters the citric acid cycle

What is the fate of fumarate produced in the urea cycle?

oxidation

glyceraldehyde-3-phosphate produces NADH.

Ketogenic amino acids

This are converted to acetyl-CoA or acetoacetyl-CoA.

Argininosuccinate synthetase

This uses ATP in the urea cycle.