2.6-2.7 : proteins and enzymes unit 1

activation energy

the minimum amount of energy needed for a reaction to happen

active site

a specific region on an enzyme where the substrate binds and the reaction takes place

amino acid

the monomers containing an amino group (NH2) a carboxyl group (COOH) and a variable R group that make up proteins

catalysis

increasing the rate of a chemical reaction via the reduction in activation energy

collagen

a type of fibrous protein that provides strength to many different cell types and makes up connective tissues

competitive inhibitors

a molecule which binds to the active site of an enzyme and prevents the substrate from binding

denaturation

upon exposure to high temperatures or extremes of pH, the permanent change in the tertiary structure of an enzyme and the shape of its active site, preventing it from carrying out its cellular function

enzyme product complex

the temporary complex formed after the enzyme has catalysed the reaction but before the products have left the active site of the enzyme

enzyme substrate complex

the temporary complex formed when the substrate binds to the active site of the enzyme

enzyme

a protein molecule that acts as a biological catalyst, reduces activation energy and increases the rate of biochemical reactions

extracellular enzyme

an enzyme which works outside of cells

fibrous protein

a class of long chain proteins that are generally insoluble in water and typically have structural roles

globular protein

a class of spherical shaped proteins that are generally water soluble and typically have metabolic roles

haemoglobin

a type of conjugated globular protein used to transport oxygen that is made up to four polypeptide chains each containing a haem prosthetic group

immobilised enzymes

enzymes which are attached to an inert, insoluble material over which the substrate passes and the reaction takes place

induced fit hypothesis

a model of enzyme action that describes how once a specific substrate binds to the active site, the enzyme undergoes subtle conformational changes to fit the substrate better

intracellular enzyme

an enzyme that works within cells

lock and key hypothesis

a model of enzyme action that describes how the enzyme will only fit a substrate that has the correct complementary shape to the active site

metabolism

the sum of all the enzyme controlled chemical reactions taking place in a cell

monohybrid inheritance

a genetic cross between two homozygous organisms

monomer

an individual unit that can be bonded to other identical monomers to make a polymer

non competitive inhibitors

and inhibitor which binds to a different part of an enzyme known as the allosteric site and prevents the enzyme from functioning

peptide bond

a bond formed between the carboxyl group of one amino acid and the amino group of another in a condensation reaction

pH

a measure of the acidity or alkalinity of a solution based inversely on the concentration of H* ions

polymer

a molecule made from many repeating monomers joined together

polypeptide

molecules formed by the condensation of many amino acids

primary structure

the individual sequence of amino acids in a protein

proteins

polymers of amino acids

rate of reaction

the change in concentration of reactants or products over time

secondary structure

the local interactions of the amino acids in the polypeptide chain

substrate specificity

the ability of an enzyme to catalyse only a specific reaction or set of reactions which have substrates complementary to the active site of the enzyme

substrate

the molecules that is acted upon by an enzyme

tertiary structure

the way that the whole protein folds to make a three dimensional structure