IB Biology HL: C1.1 - Enzymes and Metabolism

vocab/concepts!

metabolism

chemical process that converts food into energy and building blocks for the body

anabolic reaction

metabolic process that builds complex molecules from simpler ones

catabolic reaction

process that speeds up chemical reactions in living reactions

enzyme

protein that speeds up chemical reactions in living organisms

intracellular enzyme

enzymes that work inside cells to catalyze chemical reactions

extracellular enzyme

enzyme secreted by a cell to break down substances outside the cell

catalyst

substance that speeds up a chemical reaction without being consumed

rate of reaction

speed at which reactions are converted into products in a chemical reaction

activation energy

minimum energy needed to start a chemical reaction

substrate

molecule on which an enzyme acts

active site

the region of an enzyme where the substrate binds

enzyme-substrate specificity

ability of an enzyme to bind only a particular substrate

conformational change

change in the shape of a protein that affects its function

induced-fit model

explains how an enzyme changes shape to fit its substrate during binding

collision theory

states that reactions occur when particles collide with enough energy and proper orientation

immobilization

attachment of enzymes to a solid surface to restrict their movement while they remain active

denaturation

the loss of a protein’s normal shape and function due to factors like heat or pH changes

saturation

the point at which all enzyme active sites are occupied by substrate

endotherms

organisms that maintain a constant body temperature using internal heat

ectotherms

organisms whose body temperatures depends on the external environment

inhibition

reduction of enzyme activity by a substrate that interferes with the reaction

inhibitor

substance that slows down/stops an enzyme-catalyzed reaction

competitive inhibition

when a substance competes with the substrate for an enzyme’s active site

noncompetitive inhibition

when a substance binds to an enzyme away from the active site, reducing its activity

allosteric site

region on an enzyme where molecules can bind to regulate its activity

statins

drugs that lower cholesterol by inhibiting the enzyme HMG-COA reductase

feedback inhibition

when the end product of a pathway stops an enzyme earlier in the same pathway

antibiotic

substance that kills/stops the growth of bacteria

penicillin

antibiotic that kills bacteria by weakening their cell walls