unit 3 study

Enzyme

A biological protein catalyst that speeds up chemical reactions by lowering the activation energy required for the reaction to occur.

Active Site

The specific region of an enzyme where the substrate binds based on a compatible shape and charge.

Denaturation

The process where an enzyme loses its specific shape and functional ability due to environmental changes like extreme temperature or pH.

Competitive Inhibitor

A molecule that binds to the active site of an enzyme, physically blocking the substrate from entering.

Non-competitive Inhibitor

A molecule that binds to a different part of the enzyme (allosteric site), changing the enzyme's shape so the active site no longer functions.

Photosynthesis

The process of converting light energy into chemical energy, consisting of light-dependent reactions and the Calvin cycle.

Chemiosmosis

The process where a hydrogen ion (proton) gradient is used to power ATP synthase to generate ATP.

Photophosphorylation

The specific production of ATP using light energy to drive the electron transport chain in photosynthesis.

Calvin Cycle

The second stage of photosynthesis that takes place in the stroma and uses CO2, ATP, and NADPH to build sugars like G3P.

Glycolysis

A metabolic pathway in the cytosol that breaks down one glucose molecule into two pyruvates, yielding a net of 2 ATP and NADH.

Krebs Cycle

A series of reactions in the mitochondrial matrix that oxidizes acetyl CoA, releasing CO2 and generating high-energy electron carriers (NADH and FADH2).

Oxidative Phosphorylation

The production of ATP in cellular respiration powered by the electron transport chain and chemiosmosis, using oxygen as the final electron acceptor.

Fermentation

An anaerobic process that allows glycolysis to continue by regenerating NAD+ in the absence of oxygen, producing byproducts like lactic acid or alcohol.

Dynamic Homeostasis

The steady-state internal environment that biological systems maintain through constant energy input and regulation.

Second Law of Thermodynamics

The principle that energy naturally spreads out (entropy increases) unless organisms actively use energy to maintain order.