CAIE Biology IGCSE Topic 4: Biological Molecules

Vocabulary practice flashcards generated from CAIE Biology IGCSE Topic 4: Biological Molecules notes.

Active site

A specific region of an enzyme where the substrate binds and the reaction takes place.

Amino acids

Small molecules from which proteins are synthesised.

Antibodies

Proteins produced by lymphocytes in response to a specific antigen, triggering an immune response. Antibodies have binding sites complementary to a particular antigen.

Antigen

A unique chemical present on the surface of a cell that induces an immune response.

Benedict’s test

A chemical test used to test for reducing sugars that produces a different colour based on the amount of reducing sugar present.

Biuret test

A chemical test that produces a purple colour in the presence of protein.

Carbohydrate

A large molecule that is synthesised from simple sugars.

Cellulose

A type of carbohydrate made from many glucose molecules joined together. It is the main component of the cell wall in plants.

Complementary base pairing

Describes how cross-links form between complementary base pairs. A pairs with T and C pairs with G.

DCPIP test

A chemical test for vitamin C. Upon the addition of DCPIP, a colour change from blue to colourless indicates a positive test.

DNA

A double-stranded polymer of nucleotides, wound to form a double helix, that carries the genetic code.

Emulsion test

A chemical test that produces a cloudy emulsion when performed on lipids.

Fats

Lipids that are solid at room temperature.

Fatty acids

Small molecules from which fats are synthesised (along with glycerol). A molecule of fat contains three fatty acid molecules.

Glucose

A small molecule from which many carbohydrates (e.g. glycogen, starch, cellulose) are synthesised.

Glycerol

A component of fat molecules.

Glycogen

A type of carbohydrate made from many glucose molecules joined together. It serves as an energy store in animals.

Iodine test

A chemical test that produces a blue/black colour when iodine solution is added to a sample containing starch.

Lipids

A group of large molecules that are synthesised from fatty acids and glycerol.

Nucleotides

The monomers of DNA consisting of a five-carbon sugar, a phosphate group and one of four chemical bases (A, T, C, G) attached to the sugar.

Oils

Lipids that are liquid at room temperature.

Protein

A large molecule that is synthesised from amino acids.

Solvent

A substance which other solutes are dissolved in e.g. water.

Starch

A type of carbohydrate made from many glucose molecules joined together. It serves as an energy store in plants.