ap bio

Enzyme

A biological catalyst (usually a protein) that speeds up chemical reactions by lowering activation energy

Activation Energy

The energy required to start a chemical reaction

Active Site

The specific region of an enzyme where the substrate binds

Substrate

The reactant an enzyme acts on

Induced Fit

Model describing how an enzyme changes shape slightly to better fit the substrate

Denaturation

Loss of enzyme shape and function due to temperature, pH, or other environmental changes

Competitive Inhibitor

A molecule that competes with the substrate by binding to the enzyme’s active site

Noncompetitive Inhibitor

A molecule that binds to an enzyme away from the active site and changes its shape

Catalyst

A substance that speeds up a reaction without being consumed

ATP

A molecule that stores and transfers energy for cellular processes

Exergonic Reaction

A chemical reaction that releases energy (ΔG < 0)

Endergonic Reaction

A chemical reaction that requires energy input (ΔG > 0)

Photosynthesis

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

Light Reactions

First stage of photosynthesis where light energy is converted into ATP and NADPH

Calvin Cycle

Second stage of photosynthesis where CO₂ is fixed to form sugars

Chlorophyll

Pigment that absorbs light energy for photosynthesis

Cellular Respiration

Process by which cells break down glucose to produce ATP

Glycolysis

First stage of cellular respiration that breaks glucose into pyruvate

Krebs Cycle

Stage of respiration that produces electron carriers (NADH, FADH₂)

Electron Transport Chain

Final stage of respiration where most ATP is produced

Oxygen

Final electron acceptor in the electron transport chain

Fitness

Ability of an organism to survive and reproduce in a given environment