A Level Biology - Proteins

amino acids

An organic molecule containing a carboxyl group and an amino group; serves as the monomer of proteins.

peptide bond

The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction.

dipeptide

A combination of two amino acids united by means of a peptide bond.

polypeptide

A polymer (chain) of many amino acids linked together by peptide bonds.

disulfide bond

chemical side bonds that are formed when the sulfur atoms in two adjacent protein chains are joined together.

Globular protein

More 3-dimensional in shape and are mostly water soluble

Haemoglobin

a protein containing iron, found in red blood cells, which carries oxygen

Collagen

A protein fiber with a unique triple-helix that gives it great strength. Tissues with a lot of collagen fibers are typically very strong, e.g. bone, tendons, ligaments, etc.

Denaturation

A process in which a protein unravels, losing its specific structure and hence function; can be caused by changes in pH or salt concentration or by high temperature.

Protease

An enzyme that digests proteins by hydrolysis.

alpha helix

A spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure.

Tertiary structure

Irregular contortions of a protein molecule due to interactions of side chains involved in hydrophobic interactions, ionic bonds, hydrogen bonds, and disulfide bridges.