Unit 4: Cellular Energy and Metabolism

Autotrophs

Organisms that produce their own food.

Heterotrophs

Organisms that consume other organisms for energy.

Activation Energy

Minimum energy required for a chemical reaction.

Exergonic Reaction

Releases energy during the reaction process.

Endergonic Reaction

Absorbs energy from surroundings during reaction.

Temperature

Measure of thermal energy in a system.

Entropy

Measure of disorder or randomness in a system.

Metabolism

All chemical reactions in an organism.

Cellular Respiration

Process of converting glucose into ATP.

Photosynthesis

Process of converting sunlight into chemical energy.

ATP (Adenosine Triphosphate)

Energy currency of the cell.

ADP (Adenosine Diphosphate)

Formed when ATP loses a phosphate group.

Energy Coupling

Using energy from exergonic reactions to drive endergonic reactions.

Catalyst

Substance that lowers activation energy of a reaction.

Enzyme

Biological catalyst that speeds up reactions.

Substrate

Reactant molecule that an enzyme acts upon.

Active Site

Region on an enzyme where substrate binds.

Coenzyme

Organic molecule that assists enzyme function.

Inhibitor

Substance that decreases enzyme activity.

Allosteric Regulation

Regulation of enzyme activity through binding at a site other than the active site.

Feedback Inhibition

Process where the end product inhibits an earlier step.

Glycolysis

First step in cellular respiration, breaking down glucose.

Krebs Cycle

Series of reactions to produce energy carriers from acetyl-CoA.

Electron Transport Chain

Series of proteins that transfer electrons to produce ATP.

Chemiosmosis

Process of ATP production using proton gradient.

Fermentation

Anaerobic process to produce energy without oxygen.

Photosystems

Protein-pigment complexes in chloroplasts for photosynthesis.

Chlorophyll

Green pigment involved in photosynthesis.