AP Biology - Enzymes

enzyme

a protein catalyst that speeds up a chemical reaction

red

Which line (red or blue) represents an enzyme catalyzed reaction?

blue

Which line (red or blue) represents an uncatalyzed reaction?

progress of reaction

What is the x-axis of this graph?

energy

What is the y-axis of this graph?

activation energy

What is the "hill" of this graph called?

decrease

Does an enzyme increase or decrease the activation energy of a reaction?

substrate

the reactant in an enzyme catalyzed reaction

active site

the region on the enzyme where the substrate binds

active site

What is the arrow pointing at?

products

What is the arrow pointing at?

reaction rate

a measure of how fast an enzyme catalyzed reaction occurs

enzyme activity

another word for reaction rate

optimum conditions

the temperature and pH where enzyme activity is highest

denaturation

destruction of the active site of the enzyme by breaking the weak bonds of the secondary, tertiary, and quaternary structures

denaturation/loss of 3D Shape

What has happened to this protein?

high temperatures or changes in pH

What are two environmental factors that can denature a protein?

inhibitor

prevents the substrate from binding to the enzyme, decreasing enzyme activity

competitive inhibitor

binds to the enzyme at the active site and blocks the substrate from binding

competitive inhibitor

What kind of inhibitor is this?

noncompetitive inhibitor

binds to the enzyme somewhere other than the active site and changes the shape of the active site

noncompetitive inhibitor

What kind of inhibitor is this?

enzyme concentration

What is the x-axis on this graph?

enzyme activity

What is the y-axis on this graph?

pH

What is the x-axis on this graph?

enzyme activity

What is the y-axis on this graph?

optimum pH

What does the green x represent?

substrate concentration

What is the x-axis on this graph?

enzyme activity

What is the y-axis on this graph?

point of saturation

What does the green x represent?

temperature

What is the x-axis on this graph?

optimum temperature

What does the green x represent?

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.

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 that absorbs free energy from its surroundings.

exergonic

Reaction that proceeds with a net release of free energy.

energy coupling/ATP couples...

The use of an exergonic process to drive an endergonic one.

catalyst

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

enzyme substrate complex

When an enzyme binds to its substrate, it forms:

coenzymes and cofactors

What are two types of activators?

Cofactor

inorganic compound example heme

Coenzyme

Non-protein Organic helpers, example thiamin and vitamin B1

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) allosteric site and changes the structure of the active site

by lowering the activation energy required for the reaction to occur

How do enzymes catalyze reactions?

Temperature, pH and Concentration of the Substrate

An enzyme's activity can be affected by what three factors?

Breakdown of H2O2

What reaction does catalase catalyze?

activation and inhibition

What kinds of regulation exist for enzymes?

turn on the enzyme

What does activation do?

turn off the enzyme

What does inhibition do?

competitive and allosteric

What are the two types of inhibition?

What is another name for allosteric inhibition?

noncompetitive inhibition

The reactants or the product amounts

How do you measure the rate of an enzymatic reaction?

lock and key

What is the interaction between the active site and the substrate like?

they speed up reactions and lower the activation energy necessary to catalyze them

What is the advantage for using an enzyme?

the allosteric site

Where does a noncompetitive inhibitor bind?

changes the shape of the active site, by bonding to the allosteric site

What does a noncompetitive inhibitor do?

phosphorylation

the released phosphate moves to another molecule to give energy

induced fit

enzymes will change the shape of their active site to allow the substrate to bind better

allosteric activator

substrate binds to ONE active site and stabilizes the shape of the enzyme so that the active sites remain OPEN

allosteric inhibitor

substrate binds to allosteric site and stabilizes the shape of the enzyme so that the active sites are CLOSED (inactive form)

cooperatively

substrate binds to one active site (on an enzyme with more than one active site) which stabilizes the active form
CONSIDERED ALLOSTERIC REGULATION SINCE BINDING AT ONE SITE CHANGES THE SHAPE OF OTHER SITES

feedback inhibition

The end product of a metabolic pathway can act as an inhibitor to an early enzyme in the same pathway