Synthetic and naturally occurring polymers (chemistry only)

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Question 5
Medium

This question is about biological molecules and the reactions that produce them.

a.

A student investigated the fermentation of glucose by yeast. Gas bubbles were collected as the yeast respired anaerobically.

Describe a chemical test to identify the gas collected and state the expected observation.

  • Test:
  • Result:
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b.

Glucose is a simple sugar (monomer). Name two naturally occurring polymers produced from glucose.

[2]
c.

Figure 1 shows the displayed structural formula of alanine, an amino acid.

Displayed structural formula of the amino acid alanine. A central carbon atom (C) is bonded to: a hydrogen atom (H) below, a methyl group (CH3) above, an amine group (NH2) to the left consisting of a nitrogen atom (N) bonded to two hydrogen atoms (H), and a carboxylic acid group (COOH) to the right consisting of a carbon atom (C) double-bonded to an oxygen atom (O) and single-bonded to an oxygen atom (O) which is bonded to a hydrogen atom (H).

How many functional groups are there in the alanine molecule shown in Figure 1?

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d.

Alanine molecules react by condensation polymerisation to form a polypeptide.

Name the other substance produced in this reaction.

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e.

Amino acids contain nitrogen, which is not present in glucose.

Which two gases from Earth's early atmosphere could have provided nitrogen to form amino acids in early organisms?

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f.

The synthesis of proteins in organisms is controlled by DNA.

Describe the shape and structure of a DNA molecule.

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Synthetic and naturally occurring polymers (chemistry only) Questions

  1. GCSE
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