AQA AS Biology

Revision Notes

1.1.4 Glucose

The Two Forms of Glucose

  • The most well-known carbohydrate monomer is glucose ATP
  • Glucose has the molecular formula C6H12O6
  • Glucose is the most common monosaccharide and is of central importance to most forms of life
  • There are different types of monosaccharide formed from molecules with varying numbers of carbon atom, for example:
    • Trioses (3C) eg. glyceraldehyde
    • Pentoses (5C) eg. ribose
    • Hexoses (6C) eg. glucose
  • Glucose exists in two structurally different forms – alpha (α) glucose and beta (β) glucose and is therefore known as an isomer
    • This structural variety results in different functions between carbohydrates

The Two Forms of Glucose, downloadable AS & A Level Biology revision notes

Straight chain and ring structural formula of alpha & beta glucose

  • Different polysaccharides are formed from the two isomers of glucose

Structure of Polysaccharides Table

Table 4 The two forms of glucose, downloadable AS & A Level Biology revision notes

Exam Tip

You must be able to recognise and draw the isomers of α and β glucose.

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While studying Biochemistry at Oxford University, Amelia started her own tutoring service, helping to connect Science tutors with students in her local area. Amelia has experience teaching the sciences and Maths at all levels to UK and international students and, as well as being our Biology Lead, designs revision resources for Chemistry.

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