A level Bio 1.1 Monomers and Polymers

Galacto-oligosaccharides (GOS) are polymers of galactose.

Explain why GOS are described as polysaccharides. (2)

Any two from:

1. Galactose is a monosaccharide/monomer

2. (Polysaccharide is a) carbohydrate polymer

3. (Several) monosaccharides/monomers/galactose joined by condensation reactions

Explain why amylase produced in the human digestive system does not digest GOS.(2)

Active site (only) complementary to starch (1)

Due to tertiary structure (1)

Prebiotics are foods used to promote good health in humans.

Prebiotics stimulate the growth of ‘healthy’ bacterial populations in the human digestive system.

The bacteria in these ‘healthy’ populations produce enzymes that hydrolyse GOS. Suggest how GOS can work as a prebiotic. (3)

Provides galactose/sugar/monosaccharide (1)

(Bacteria use the galactose/sugar) for respiration (1)

(Bacteria use the galactose/sugar) for binary fission (1)

Describe the chemical reactions involved in the conversion of polymers to monomers and monomers to polymers.

Give two named examples of polymers and their associated monomers to illustrate your answer. (5)

A condensation reaction joins monomers together and forms a (chemical) bond and releases water(1)

A Hydrolysis reaction breaks a (chemical) bond between monomers and uses water (1)

Suitable examples(2 points) : nucleotides and polynucleotide(phosphodiester bond) , Amino acid and polypeptide (peptide bond) , Beta glucose and cellulose (beta glycosidic bond)

Rf to a correct bond within a named polymer

What is a monomer?

(a monomer is a smaller / repeating) unit / molecule from which larger molecules / polymers are made