Alternative Metabolic Pathways: Protein and Lipid Catabolism

Vocabulary flashcards covering the alternative metabolic pathways for energy generation, including protein catabolism, deamination, lipid breakdown, beta oxidation, and anabolism.

Glucose

The primary and most efficient carbohydrate sugar utilized by organisms as an energy source, yielding $36$ ATP molecules.

Protein Catabolism

The metabolic breakdown of proteins that generally occurs when glucose or lipids are scarce, supplying substrates for the Krebs cycle as well as nitrogen and sulfur compounds.

Proteases

Proteolytic enzymes located outside of prokaryotic cells that digest large protein macromolecules into monomer amino acids so they can enter the cell.

Deamination

An intracellular reaction that involves the removal of the nitrogen-containing amino group from an amino acid.

Ammonia

A nitrogenous waste molecule formed from the removed amino group during deamination that must be eliminated from the cell if not recycled.

Lipid Catabolism

The metabolic process of breaking down lipids into glycerol and fatty acids to produce energy carriers, ATP, and metabolic substrates.

Lipases

Enzymes that break down lipids by detaching the glycerol molecule from the fatty acids.

DHAP

The molecule into which glycerol is converted, serving as a substrate that feeds directly into glycolysis to eventually produce pyruvate.

Beta Oxidation

The process that breaks down fatty acids by splitting hydrogenated carbon atoms from the carbon backbone and joining them to coenzyme A to produce acetyl CoA.

Acetyl CoA

The molecule produced when fatty acid carbons join to coenzyme A during beta oxidation, which then enters the Krebs cycle to generate ATP, NADH, and $FADH_2$.

Anabolism

The metabolic process of building up specific macromolecules required for cellular purposes and functions, utilizing existing metabolic pathways coupled with distinct enzymes.