ch8 - metabolism, enzymes higher biology

ch8

Metabolism

all the chemical reactions that take place inside living cells

transition state -

an unstable, high-energy state during a chemical reaction.

reversible

• a chemical pathway that can proceed in both directions (forwards + backwards)

anabolic-

A process in which large molecules are built from small molecules. Requires energy.

enzyme-

Biological catalyst that speeds up reactions by lowering the activiation energy of that reaction.

catabolic

• A process in which large, complex molecules are broken down into smaller ones, releasing energy.

end product inhibition-

when the final product of a metabolic pathway builds up and shuts down its own production by blocking an enzyme earlier in the pathway.

control variable

-A variable that is kept constant during an experiment.

allosteric site-

A site on an enzyme other than the active site, to which a specific substance binds, thereby changing the shape and activity of the enzyme.

active site-

the specific region on an enzyme where substrate molecules bind and a chemical reaction takes place.

competitive inhibitor

-A substance that reduces the activity of an enzyme by binding to the enzyme's active site in place of the substrate.

Dependent variable

-a factor that you measure or record during an experiment

Non - Competitive inhibitor

-a molecule that reduces enzyme activity by binding to a site other than the active site (the allosteric site).

Irreversible

-a reaction that cannot be undone or reversed.

Pore-

a tiny opening or channel found through the cell membrane, where molecules cross the membrane by diffusion.

Activation energy-

the minimum amount of energy required to start a chemical reaction.

Affinity

-the chemical attraction between a substrate (or inhibitor) and an enzyme's active site.

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.

catalyst

-a substance that speeds up the rate of a chemical reaction without being changed or used up in the process.

protein

-a large molecule made up of amino acids linked together by peptide bonds.

denatured-

a permanent change in the shape of an enzyme, making it non-functional

pump

-protein in the cell membrane that uses energy to move molecules/ions against a concentration gradient.

substrate-

A specific reactant acted upon by an enzyme

independant variable

-variable that is changed in an experiment

orientation-

the specific physical direction, alignment, or positioning of an object or organism

reliable

-how consistent or repeatable the experimental results are

Phospholipid

-a type of lipid molecule that forms the main structural component of all cell membranes

diffusion

-Movement of molecules from an area of higher concentration to an area of lower concentration.

active transport

-the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.