A-Level Biology AQA 7402

1.2: Carbohydrates

#1.2.1

Monosaccharides are the monomers from which larger carbohydrates are made. Glucose, galactose and fructose are common monosaccharides.

#1.2.2

A condensation reaction between two monosaccharides forms a glycosidic bond.

#1.2.3

Disaccharides are formed by the condensation of two monosaccharides:

  • maltose is a disaccharide formed by condensation of two glucose molecules
  • sucrose is a disaccharide formed by condensation of a glucose molecule and a fructose molecule
  • lactose is a disaccharide formed by condensation of a glucose molecule and a galactose molecule.
#1.2.4

Glucose has two isomers, α-glucose and β-glucose, with structures:

mtaimg/images/sections/643/643-4-1.png/mtaimg

#1.2.5

Polysaccharides are formed by the condensation of many glucose units.

  • Glycogen and starch are formed by the condensation of α-glucose.
  • Cellulose is formed by the condensation of β-glucose.
#1.2.6

The basic structure and functions of glycogen, starch and cellulose. The relationship of structure to function of these substances in animal cells and plant cells.

#1.2.7

Biochemical tests using Benedict's solution for reducing sugars and non-reducing sugars and iodine/potassium iodide for starch.

1.1
Monomers and polymers
1.3
Lipids
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