AP Bio Chapter 3 Enzymes Practice Test

catalyst

speeds up reaction by lowering activation energy/increasing rate, does NOT cause reactions

enzymes

proteins that act as biological catalysts, does not change in chemical reaction

Ribozymes

RNA molecules that function as enzymes

reactants

substrate, binds to active site

Energy Barrier/ Transition state

activation energy, energy needed to start a reaction

enzyme-substrate complex

when a substrate binds to the active site of an enzyme

inducing strain

enzyme stretches substrate causing it to go into transition state

substrate orientation

enzymes bring specific atoms to create bonds to lower activation energy

adding chemical groups

R-groups (amino acids) are added to break covalent bonds on the substrate

induced fit

The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.

cofactors

inorganic ions that bind to enzymes

prosthetic group

permanently bound to enzyme

saturated

all of enzymes active sites are full of substrate, plateau on graph

turnover rate

how long it takes for an enzyme to catalyze a reaction

metabolic pathways

product of a reaction is a substrate for the next reaction

Homeostasis

The maintenance of stable internal conditions

irreversible inhibition

inhibitor covalently bonds in the active site and permanently inactivates the enzyme

competitive reversible inhibition

inhibitor binds to active site, temporarily stops reactions

noncompetitive reversible inhibition

inhibitors bind to allosteric site, changes enzyme shape, slowing reaction rate down

allosteric regulation

molecule binds to enzyme (anywhere but the active site)

covalent modification

addiction of covalent molecules that change enzyme shape

noncovalent bonding

formation of hydrogen or ionic bonds; typically reversible

protein kinase

The enzyme that transfers phosphate groups from ATP to protein.

commitment step

the first reaction in a metabolic pathway

feedback inhibition

end product is in high concentration and binds to enzyme causing inactivation, stopping the production of the product (to save energy/resources)

law of mass action

the higher the H+ concentration, the more reaction is driven to the left (nonionic glutamic acid) to the less hydrophilic form.

temperature

warming increases chemical reaction rate to an extent (denature at certain degree)

isozymes

2 enzymes that can catalyze the same reaction