AP Biology Enzymes

Metabolism

the totality of an organisms chemical reactions that result from interactions between molecules within the cell

metabolic pathway

a sequence of chemical reactions undergone by a compound in a living organism, start with substrate end with product

catabolic

breaking a complex molecule down into its simpler parts, releasing energy. ie. cellular respiration

anabolic

using energy to build complex molecules from simpler molecules. ie. protein synthesis

Bioenergetics

the study of how organisms manage their energy resources

energy

capacity to cause change, do work

heat(thermal energy)

kinetic energy associated with random movement of molecules

chemical energy

potential energy available for release in a chemical reaction, energy within bonds

exergonic reaction

a reaction with a net release of free energy, negative free energy, spontaneous

endergonic reaction

a reaction that absorbs free energy from its surroundings, non-spontaneous, positive free energy

catalyst

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

enzymes

a catalytic protein, speeds up metabolic reactions by lowering activation energy, very specific, reusable, unchanged by reaction

activation energy

initial energy needed to start a chemical reaction, free energy for activating reaction, given off by heat

induced fit

brings the chemical groups of the active site into positions that enhance their ability to catalyze the reaction, makes the enzyme more effective

cooperativity

another type of allosteric activation, binds to one active site but locks ALL active sites open, allowing products to be constantly produced

Substrate

the REACTANT that an enzyme acts on

Enzyme-Substrate Complex

The enzyme and substrate bound together

Active Site

region on the enzyme where substrate binds

Hydrogen and Ionic Bonds

substrate held in active site by WEAK interactions

Lock and Key

active site on enzyme fits substrate exactly

Ways enzymes lower activation energy

can do this by having a favorable environment, straining substrate molecules, orienting substrates correctly

hydrolysis

The addition of water to a polymer to split it into monomers.

cofactors

non-protein enzyme helpers ex. zinc, iron, copper

coenzymes

organic enzyme helpers

Denature

A change in the shape of a protein (such as an enzyme) that can be caused by changes in temperature or pH (among other things).

Renature

removing reagent that denatures protein brings to this state

Feedback inhibition

A method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway.

Allosteric Regulation

can accelerate or inhibit production and enzyme activity by attaching to another part of the protein. this changes the shape of the active site which inhibits substrates from bonding and producing more products

Activator

one of the allosteric regulators, stabilizes and keeps active site open for production, wedges open

Inhibitor

a substance that interferes with the action of a catalyst

Competitive Inhibitor

inhibitor that mimics original substrate by blocking the original substrate

noncompetitive inhibitor

bind to another part of enzyme to change shape and block substrate from producing

Conditions that affect enzymes

environment, pH, temp, salinity, chemicals that infuse enzyme, increase activity by increasing substrate concentration