AP bio unit 3

ATP

Adenosine triphosphate; the main energy source that cells use for most of their work.

ADP

Adenosine diphosphate; molecule that ATP becomes when it gives up one of its three phosphate groups.

Free Energy

Chemical energy available to do work.

Autotroph

An organism that lives exclusively on inorganic materials, water, and an energy source other than chemical bonds of organic compounds.

Heterotroph

An organism that requires preformed organic molecules as sources of energy and chemical building blocks.

Metabolism

The sum of the building and breaking reactions occurring in cells.

Catabolic Pathways

Series of reactions that release energy by breaking down complex molecules into simpler compounds.

Anabolic Pathways

Series of reactions that consume energy to build complicated molecules from simpler ones.

Phosphorylation

The enzyme-mediated direct transfer of phosphate from another molecule to ADP.

Oxidation

Relative loss of electrons in a chemical reaction; associated with the liberation of energy.

Reduction

Gain of electrons by a chemical reactant; accompanied by an oxidation.

NAD+

Nicotinamide adenine dinucleotide; a coenzyme that is an electron carrier.

Cellular Respiration

The catabolic pathways by which electrons are removed from molecules and passed through intermediate carriers to O2, generating H2O and releasing energy.

Aerobic Respiration

Respiration that requires molecular oxygen (O2).

Anaerobic Respiration

Respiration that occurs without the use of molecular oxygen (O2).

Pyruvate

A three-carbon compound that forms as an end product of glycolysis.

Endergonic Reaction

A reaction that absorbs free energy from its surroundings.

Exergonic Reaction

A reaction that proceeds with a net release of free energy.

Alcohol Fermentation

Anaerobic series of reactions that convert glucose to ethanol and carbon dioxide.

Lactic Acid Fermentation

Anaerobic reactions that convert glucose to lactic acid.

Krebs Cycle

A set of chemical reactions in cellular respiration that oxidize acetyl CoA to carbon dioxide.

Photosynthesis

Metabolic processes by which light is converted into energy to produce organic compounds from CO2.

Light Reactions

The initial phase of photosynthesis where light energy is converted into chemical energy.

Chlorophyll

Green pigments associated with chloroplasts that trap light energy for photosynthesis.

Absorption Spectrum

Graph of light absorption versus wavelength showing how much light is absorbed at each wavelength.

Action Spectrum

Graph of a biological process versus light wavelength showing which wavelengths are involved.

Light-Harvesting Complex

A group of molecules that cooperate to absorb light energy and transfer it to a reaction center.

Photosystem

A light-harvesting complex in the chloroplast thylakoid composed of pigments and proteins.

Calvin Cycle

A series of enzyme-assisted reactions that produce a three-carbon sugar.

Enzyme

A protein that speeds up reactions, typically ending in ‘ase’.

Catalyst

A chemical agent that speeds up a reaction without being consumed.

Activation Energy

The energy needed to push the reactants over an energy barrier.

Enzyme-Substrate Complex

When an enzyme binds to its substrate.

Active Site

A pocket or groove on the enzyme surface where the substrate can bind.

Induced Fit Model

States that the enzyme and substrate undergo conformational changes to interact fully.

Competitive Inhibitors

Substances that reduce enzyme productivity by blocking substrates from entering active sites.

Noncompetitive Inhibitors

Agents that impede reactions by binding to another part of the enzyme.

Saturated Enzyme

Describes an enzyme's maximum activity when every active site is being used.

Denaturation

A change in protein shape that stops the protein from functioning.