AP Bio Enzyme Mini-Unit 2024

metabolism

All of the chemical reactions that occur within an organism

Adenine Triphosphate (ATP)

Modified nucleotide used to store and release energy. This is because the bonding of the phosphate groups is unstable.

exergonic

releases energy, spontaneous

catabolic

To break down

endergonic

requires/absorbs energy

anabolic

To build up

energy coupling

Using exergonic (catabolic) reactions to fuel endergonic (anabolic) reactions

phosphorylation

Transfer of a phosphate group to a molecule

enzyme that phosphorylates

kinase

ADP

Lower energy molecule that can be converted into ATP. Also the compound that remains when a phosphate group is removed from ATP, releasing energy.

catabolic/exergonic pathways

Release energy by breaking down complex molecules into simpler compounds

anabolic/exergonic pathways

Consume energy to build complex molecules from simpler ones

Potential energy

Energy that matter possesses because of its location or structure

Chemical energy

Potential energy available for release in a chemical reaction

Change in free energy

∆G

∆G = ∆H - T∆S

Change in total energy or enthalpy (∆H) - change in entropy (T∆S)= change in free energy (∆G)

entropy

measure of disorder

enthalpy

total energy of a system

Only processes with ____ are spontaneous

negative ∆G

Exergonic reaction

Releases energy, spontaneous. Reactants > Products, so negative ∆G

Endergonic reaction

Absorbs energy, nonspontaneous. Products > Reactants, so positive ∆G

enzymes

proteins that speed up metabolic reactions without being consumed by the reaction, they lower energy barriers

enzymes do not

change ∆G, they just lower activation energy

substrate

reactant of an enzyme-catalyzed reaction

active site

the region on the enzyme where the substrate binds

induced fit of a substrate

brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction

active site can lower an EA barrier by

Orienting substrates correctly

Straining substrate bonds

Providing a favorable microenvironment

Covalently bonding to the substrate

enzyme activity can be affected by

temperature, pH, chemicals (that specifically influence the enzyme), relative concentrations of substrates and products

When do enzymes denature?

too high or too low pH and high temperatures

Denature

Loses structure, thus losing its function

cofactors

nonprotein enzyme helpers

coenzyme

organic cofactors

competitive inhibitors

binds to the active site of an enzyme, competing with the substrate

noncompetitive inhibitors

binds to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

allosteric regulation

The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.

feedback inhibition

the end product of a metabolic pathway shuts down the pathway, this prevents a cell from wasting chemical resources by synthesizing more product than is needed