AP Bio - Energy and Enzymes

calder

metabolism

The sum of the building & breaking reactions occurring in cells

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.

thermal energy

Kinetic energy associated with the random movement of molecules or atoms. (heat)

potential energy

Stored energy.

first law of thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

second law of thermodynamics

With every energy transfer, some energy becomes unusable. (Entropy of universe increases)

free energy

Measures the portion of a cell's energy that is available to do work (G)

endergonic reaction

Reaction that absorbs free energy from its surroundings. Non-spontaneous! Energy REQUIRED. (+DG)

exergonic reaction

Reaction that proceeds with a net release of free energy. Spontaneous - ENERGY RELEASED. (-DG)

energy coupling

Capturing energy from an exergonic reaction and passing it to an endergonic one. Usually done with ATP.

ATP (adenosine triphosphate)

Composed of a sugar ribose, nitrogenous base adenine, and a chain of three phosphate groups bonded to it.

phosphorylation

The metabolic process of adding a phosphate group into an organic molecule.

catalyst

Any chemical agent that speeds up a reaction. Written above the arrow in a chemical equation

enzyme

Protein catalyst that speeds up reactions in our body. Typically end in "ase" (ex. Peroxidase, Lipase)

enzyme-substrate complex

When an enzyme binds to its substrate, it forms this:

active site

A pocket or groove on the surface of the enzyme where a substrate can bind.

induced fit model

States that the enzyme and substrate undergo conformational changes to interact fully with one another (as opposed to "Lock & Key")

cofactor

Inorganic metal ion helpers that bind to enzymes to help to assume correct shape (Ex. Zn).

coenzyme

Non-protein Organic helpers like vitamins that bind to enzymes to help them assume the correct shape. (Ex. Vitamin A)

competitive inhibitors

Reduce the productivity of enzymes by blocking substrates from entering active sites.

noncompetitive inhibitors

Impede enzymatic reactions by binding to a site other than the active site (usually bind to an allosteric site)

saturated

Describes an enzyme's maximum activity when every active site is being used.

substrate

The reactant that an enzyme binds with. It becomes the product(s)

Chemical Energy

Potential energy trapped in molecular bonds of macromolecules.

activation energy (Ea)

the initial energy needed to start a chemical reaction

Delta G

change in free energy (FINAL - INITIAL) Can be + or - (negative means energy released - exergonic / positive means energy gained - endergonic)

homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

negative feedback inhibition

A primary mechanism of homeostasis, in metabolic pathways it is where the final product behaves as an inhibitor of the pathway to prevent too much product from being made

Denatured

Change the shape of an enzyme so that it can no longer speed up a reaction. (involved UNFOLDING of tertiary structures)

optimum temperature

The temperature at which an enzyme is most active

Optimum pH

the pH at which an enzyme is most active

-ase

forms names of enzymes

Rate formula for enzyme activity

(amount 2 - amount 1)/(time2 - time1)

Phosphorylation

the addition of a phosphate group to a molecule (ex. ADP --> ATP

cell respiration

the controlled release of energy from organic compounds to produce ATP. (usually in mitochondria)