AP Biology - Unit 3 Part 1

Calvin cycle

a series of enzyme-assisted chemical reactions that produces a three-carbon sugar

autotroph

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

heterotroph

An organism that requires pre-formed organic molecules as sources of energy and chemical building blocks.

metabolism

The sum of the building & 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.

bioenergetics

The study of how organisms manage their energy resources.

kinetic energy

Energy associated with relative motion of objects.

thermal energy

Kinetic energy associated with the random movement of molecules or atoms. (heat)

potential energy

Stored energy.

free energy

Measures the portion of a system's energy that can perform work when temperature and pressure are uniform throughout the system, as in a living cell.

endergonic reaction

Reaction that absorbs free energy from its surroundings.

exergonic reaction

Reaction that proceeds with a net release of free energy.

catalyst

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

enzyme

Protein that speeds up reactions. Typically end in "ase" (ex. Peroxidase, Lipase)

activation energy

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

enzyme-substrate complex

When an enzyme binds to its substrate, it forms:

active site

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

induced fit model

States that the enzyme and substrate undergo conformational changes to interact fully with one another (as opposed to "Lock & Key"

competitive inhibitors

Reduce the productivity of enzymes by blocking substrates from entering active sites.

noncompetitive inhibitors

Impede enzymatic reactions by binding to another part of the enzyme (other than the active site).

exothermic reaction

a chemical reaction where energy is given off, so that the products have less energy than the reactants.

endothermic reaction

a chemical reaction where energy is taken in, so that the products have more energy than the reactants.

Catabolic pathway

Release energy by breaking down complex molecules into simpler ones i.e. Cellular respiration

Anabolic pathway

Consume energy to build complex molecules from simpler ones i.e. Amino acids making up proteins

Enzyme Denaturation

disruption of the enzyme's structure so that it no longer fits the substrate

Causes of enzyme denaturation

pH or temperature changes