AP Bio Unit 3 Energetics

Energy

The capacity to cause change or do work

Metabolism

The sum of all chemical reactions in a cell

Anabolic Pathway

Energy-requiring pathway that builds complex molecules

Catabolic Pathway

Energy-releasing pathway that breaks down molecules

Enzyme

Protein that speeds up chemical reactions by lowering activation energy

Activation Energy

Energy required to start a chemical reaction

Substrate

Reactant that binds to an enzyme

Active Site

Region of an enzyme where the substrate binds

Induced Fit

Change in enzyme shape upon substrate binding

Competitive Inhibitor

Molecule that competes with substrate for the active site

Noncompetitive Inhibitor

Molecule that binds elsewhere and changes enzyme shape

Cofactor

Non-protein helper required for enzyme activity

Coenzyme

Organic cofactor, often derived from vitamins

Photosynthesis

Process by which light energy is converted into chemical energy stored in glucose

Autotroph

Organism that produces its own food

Chloroplast

Organelle where photosynthesis occurs

Thylakoid

Membrane structure where light reactions take place

Granum

Stack of thylakoids

Stroma

Fluid-filled space where the Calvin cycle occurs

Chlorophyll

Primary photosynthetic pigment that absorbs light

Light Reactions

Photosynthetic reactions that convert light energy into ATP and NADPH

Photosystem II

Protein complex that splits water and initiates the light reactions

Photolysis

Splitting of water to release electrons, protons, and oxygen

Electron Transport Chain

Series of proteins that transfer electrons and pump protons

Chemiosmosis

ATP production driven by proton diffusion across a membrane

ATP Synthase

Enzyme that produces ATP using a proton gradient

Photosystem I

Protein complex that produces NADPH

Calvin Cycle

Light-independent reactions that fix carbon into sugars

Carbon Fixation

Incorporation of CO₂ into an organic molecule

RuBisCO

Enzyme that catalyzes carbon fixation

Reduction Phase

Stage of the Calvin cycle that produces G3P

Regeneration Phase

Stage that regenerates RuBP

G3P

Three-carbon sugar produced by the Calvin cycle

Cellular Respiration

Process of converting glucose into ATP

Glycolysis

Anaerobic process that breaks glucose into pyruvate

Pyruvate Oxidation

Conversion of pyruvate to acetyl-CoA

Citric Acid Cycle

Cycle that completes glucose oxidation and produces electron carriers

NADH

Electron carrier that donates electrons to the ETC

FADH₂

Electron carrier used in the ETC

Oxidative Phosphorylation

ATP production using the electron transport chain

Mitochondrion

Organelle where aerobic respiration occurs

Cristae

Inner mitochondrial membrane folds

Matrix

Innermost compartment of the mitochondrion

Substrate-Level Phosphorylation

ATP produced directly from enzyme reactions

Fermentation

Anaerobic process that regenerates NAD⁺

Lactic Acid Fermentation

Fermentation producing lactate

Alcoholic Fermentation

Fermentation producing ethanol and CO₂