AP Biology - Unit 3: Energy Flashcards

Vocabulary flashcards based on lecture notes about energy, metabolism, cellular respiration, and photosynthesis.

Heterotrophs

Organisms that take in organic compounds to make energy. (C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP)

Mitochondria

Organelle with cristae (folded membrane) and is thought to be a symbiote cell.

Glycolysis

First step in cellular respiration; breaks down glucose into pyruvate, producing ATP.

Kreb's Cycle

Second step in cellular respiration; breaks down pyruvate further, releases CO2, adds to NADH and FADH2, and makes ATP.

Electron Transport Chain

Third step in cellular respiration; electrons are transferred to make protons, which makes water and 32 ATP.

Lactic Acid Fermentation

Anaerobic process where pyruvate is converted to lactate.

Metabolism

Total energy of an organism's chemical reactions.

Catabolic Pathways

Releasing energy by breaking down complex molecules (e.g., cellular respiration).

Anabolic Pathways

Consume energy to build complex molecules.

Kinetic Energy

Energy associated with relative motion.

Thermal Energy

Random movement of atoms; a form of kinetic energy (heat).

Potential Energy

Energy that is not moving.

Chemical Energy

Energy available for release in a chemical reaction.

Free Energy

Portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system (ΔG = ΔH - TΔS).

ATP

Adenosine Tri-Phosphate; the energy currency of the cell.

Energy Coupling

Use of an exergonic process to drive an endergonic one.

Fermentation

Degradation of sugars or other organic fuels that occurs without oxygen.

Aerobic Respiration

Process where oxygen is consumed as a reactant along with organic fuel.

Anaerobic Respiration

Process that uses substances other than oxygen as reactants.

Redox Reactions

Electron transfers in chemical reactions.

Oxidation

Loss of electrons.

Reduction

Addition of electrons.

NADH

A molecule that carries electrons and stored energy that can be tapped to make ATP.

Glycolysis

Sugar splitting; the breakdown of glucose into pyruvate.

Krebs Cycle (Citric Acid Cycle)

Oxidizes organic fuel derived from pyruvate, generating ATP, NADH, and FADH2.

Chemiosmosis

The use of energy in a H+ gradient to drive cellular work; osmosis of chemicals.

Proton-motive force

The force that promotes movement of protons across membranes.

Endergonic Reaction

A reaction that requires an input of energy (also known as endothermic).

Exergonic Reaction

A reaction that releases energy (also known as exothermic).

Coenzymes

Electron carriers that shuttle high-energy electrons from glucose and intermediates to the electron transport chain.

Photosynthesis

The process used by plants, algae, and cyanobacteria to convert light energy into chemical energy.

Chlorophyll

A pigment that absorbs certain wavelengths of light and is directly involved in the light reaction.

Photosystem

Made of pigment antenna, reaction center, and electron acceptor that absorbs solar energy and passes it from pigment to pigment until it reaches the reaction center.

Rubisco

The enzyme that initially incorporates carbon dioxide into organic compounds during the Calvin cycle (Dark Reaction).