IGCSE - Biological Molecules

A sugar, such as sucrose or lactose, made up of two sugar units.

Any complex carbohydrate molecule that is a polymer of sugar units.

A storage molecule, such as starch, made of repeating sugar units.

The products of digestion of a polysaccharide.

glycogen

starch

glucose

cellulose

carbon

nitrogen

hydrogen

oxygen

To absorb water by osmosis

To absorb light energy

For cell membranes

For cell walls

Combined with magnesium ions from the roots, this substance is essential for the capture of the light energy in the chloroplasts.

Synthesised from glucose made by photosynthesis and nitrate and phosphate ions from the roots, this substance is an essential component of the nucleus.

Synthesised from glycerol and fatty acids made from the products of photosynthesis, this substance is used by plants for cell membranes and to store energy in seeds.

Synthesised from glucose made by photosynthesis, this substance is used by plants to store energy in leaves and in the roots.