Cellular Metabolism: Glucose Utilization and ATP Production (Lecture Video Notes)

Vocabulary flashcards covering glucose transport, glycolysis, pyruvate fate, TCA cycle, electron transport chain, ATP synthesis, and related energy concepts.

Glucose

Monosaccharide with the chemical formula C6H12O6; main substrate entering glycolysis.

Cell membrane (phospholipid bilayer)

The boundary of the cell; glucose cannot freely diffuse across and requires transporters.

Glucose transporters

Membrane proteins that facilitate glucose entry into cells; some are insulin-dependent.

GLUT4

Insulin-responsive glucose transporter in muscle and adipose tissue that translocates to the membrane when insulin is present.

Insulin

Hormone that promotes glucose uptake by cells by stimulating GLUT4 translocation to the cell membrane.

Glycolysis

Cytoplasmic pathway that converts glucose to pyruvate (and lactate under anaerobic conditions), yielding 2 ATP per glucose.

Pyruvate

End product of glycolysis; can enter mitochondria to form acetyl-CoA or be reduced to lactate under anaerobic conditions.

Lactate (lactic acid)

Anaerobic end product of glycolysis; regenerates NAD+ to keep glycolysis going when oxygen is limited.

Pyruvate dehydrogenase

Mitochondrial enzyme that converts pyruvate to acetyl-CoA, producing NADH in the process.

Acetyl-CoA

Two-carbon molecule that feeds the citric acid (Krebs) cycle.

Krebs cycle / Citric acid cycle

Mitochondrial cycle that oxidizes acetyl-CoA to CO2, generating NADH, FADH2, and a small amount of ATP.

NAD+/NADH

Electron carrier; NADH donates electrons to the electron transport chain; NAD+ is the oxidized form.

FAD/FADH2

Electron carrier; FADH2 donates electrons to the chain; FAD is the oxidized form.

Electron transport chain (ETC)

Series of membrane proteins in the inner mitochondrial membrane that transfer electrons to oxygen and pump protons.

Oxygen (O2)

Final electron acceptor in the ETC; necessary for complete electron transfer and ATP production.

Proton gradient / chemiosmosis

Electrochemical gradient of protons across the mitochondrial membrane that drives ATP synthesis.

ATP synthase

Enzyme that uses the proton gradient to convert ADP and Pi into ATP.

ATP

Adenosine triphosphate; the cell’s primary energy currency produced during glycolysis, TCA, and oxidative phosphorylation.

ADP

Adenosine diphosphate; substrate for ATP synthase; phosphorylation yields ATP.

ATP yield per glucose (aerobic)

Approximately 30–32 ATP per glucose under aerobic conditions; yield varies by tissue and conditions.

Substrate-level phosphorylation

Direct synthesis of ATP in glycolysis and the citric acid cycle, not via the electron transport chain.

Oxidative phosphorylation / aerobic respiration

ETC-driven ATP production using the proton gradient to drive ATP synthase.