Stages of Cellualr Resp, and Photosynthesis

Glycolysis — pathway that breaks one glucose molecule into pyruvate and produces ATP and NADH.

Glucose — 6-carbon molecule that enters glycolysis.

Pyruvate — 3-carbon product of glycolysis.

ATP — main short-term energy currency of the cell.

ADP — lower-energy form that can be converted back into ATP.

NAD⁺ — electron carrier that accepts high-energy electrons.

NADH — electron carrier carrying high-energy electrons.

Phosphorylation — addition of a phosphate group to a molecule.

Substrate-level phosphorylation — ATP production by directly transferring a phosphate group to ADP.

Cytoplasm/Cytosol — location where glycolysis occurs.

Investment phase — early part of glycolysis where ATP is used.

Payoff phase — later part of glycolysis where ATP and NADH are produced.

Glucose → Glycolysis → 2 Pyruvate + ATP + NADH

Pyruvate oxidation — process that converts pyruvate into acetyl-CoA.

Acetyl-CoA — molecule that carries the acetyl group into the citric acid cycle.

Coenzyme A (CoA) — molecule that helps transport the acetyl group.

NAD⁺ — oxidized electron carrier that accepts electrons.

NADH — reduced electron carrier carrying high-energy electrons.

CO₂ — carbon dioxide released when carbon is removed during respiration.

Citric Acid Cycle — pathway that further breaks down carbon from glucose and produces electron carriers.

Krebs Cycle — another name for the citric acid cycle.

Mitochondrial Matrix — internal space of the mitochondrion where pyruvate oxidation and the citric acid cycle occur.

Oxidation — loss of electrons.

Reduction — gain of electrons.

Redox Reaction — reaction involving the transfer of electrons.

FAD — electron carrier that can accept electrons.

FADH₂ — reduced form of FAD that carries high-energy electrons.

Substrate-level phosphorylation — direct production of ATP by transferring a phosphate group to ADP.

Pyruvate → Acetyl-CoA → Citric Acid Cycle → NADH + FADH₂ + ATP + CO₂

Electron Transport Chain (ETC) — series of proteins that transfer high-energy electrons.

Electron Carrier — molecule or protein that transports high-energy electrons.

NADH — donates high-energy electrons to the electron transport chain.

FADH₂ — also donates high-energy electrons to the electron transport chain.

Proton (H⁺) — hydrogen ion used to establish a concentration gradient.

Proton Gradient — difference in H⁺ concentration across a membrane.

Chemiosmosis — movement of H⁺ down its concentration gradient through ATP synthase.

ATP Synthase — enzyme that uses the movement of H⁺ to produce ATP.

Oxidative Phosphorylation — ATP production powered by the electron transport chain and chemiosmosis.

Oxygen (O₂) — final electron acceptor in aerobic cellular respiration.

Water (H₂O) — produced when oxygen accepts electrons and H⁺.

Inner Mitochondrial Membrane — location of the electron transport chain and ATP synthase.

NADH/FADH₂ → ETC → H⁺ Gradient → ATP Synthase → ATP

O₂ = final electron acceptor

Photosynthesis — process that converts light energy into chemical energy.

Chloroplast — organelle where photosynthesis occurs.

Thylakoid — flattened membrane structure inside a chloroplast.

Thylakoid Membrane — membrane containing the proteins involved in the light reactions.

Granum — stack of thylakoids.

Stroma — fluid surrounding the thylakoids inside the chloroplast.

Chlorophyll — pigment that absorbs light energy.

Photon — packet of light energy.

Photosystem — group of pigments and proteins involved in capturing light energy.

Photosystem II (PSII) — photosystem involved early in the light reactions.