AP Biology - Unit 3: Cellular Energetics

Flashcards about Cellular Energetics

Metabolic pathways

A linked series of enzyme-catalyzed chemical reactions occurring within a cell.

ATP (Adenosine Triphosphate)

The cell's energy currency.

Heterotrophs

Organisms that capture energy from other organic compounds.

Autotrophs

Organisms that produce their own food.

Enzymes

Biological catalysts that speed up chemical reactions by lowering activation energy.

Active site

Part of an enzyme that binds to the substrate.

Competitive Inhibitor

Binds to the active site of an enzyme, preventing substrate binding.

Non-competitive Inhibitor

Binds to an enzyme elsewhere than the active site, changing enzyme shape and reducing its activity.

Exergonic Reaction

Releases energy and increases entropy (e.g., cellular respiration).

Endergonic Reaction

Requires energy and decreases entropy (e.g., photosynthesis).

Photosynthesis

Process in chloroplasts that converts solar energy into chemical energy (glucose).

Light-Dependent Reactions

The first stage of photosynthesis which occurs in the thylakoids; inputs are light and H2O; outputs are ATP, NADPH, and O2.

Calvin Cycle

The second stage of photosynthesis which occurs in the stroma; inputs are CO2, ATP, and NADPH; output is glucose.

Cellular Respiration

Process where cells make ATP using glucose from food.

Glycolysis

The first stage of cellular respiration, occurring in the cytoplasm, where glucose is converted to 2 pyruvate, 2 ATP, and 2 NADH.

Krebs Cycle

The second stage of cellular respiration, occurring in the mitochondrial matrix, which produces CO2, ATP, NADH, and FADH2 from pyruvate.

ETC & Oxidative Phosphorylation

The third stage of cellular respiration, occurring in the inner mitochondrial membrane, where NADH/FADH2 deliver electrons, and ATP is produced via ATP synthase.

Fermentation

An anaerobic process that makes less ATP and produces lactic acid or alcohol.

Energy Coupling

The use of energy released from exergonic reactions to fuel endergonic reactions.