7.13 Natural polymers: proteins, DNA, starch and cellulose
5 exam questions worth 10 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
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What is the monomer of starch?
Choose one answer.
Correct Not quite: the answer is Glucose
Mark scheme
D
Model answer
D: starch is a polymer of glucose.
Name the two functional groups in an amino acid.
Mark scheme
- amine / –NH2 (1)
- carboxylic acid / –COOH (1)
Model answer
An amine group (–NH2) and a carboxylic acid group (–COOH).
Higher tier.
Explain why the formation of a protein from amino acids is an example of condensation polymerisation.
Mark scheme
- amino acids join together in a long chain (1)
- a molecule of water is lost at each link (1)
Model answer
Amino acid monomers join into a long chain, and a molecule of water is released each time two amino acids join.
Describe the structure of DNA.
Mark scheme
- two polymer chains (1)
- in a double helix (1)
- made of nucleotides with four different bases (A, T, C, G) (1)
Model answer
DNA is made of two polymer chains of nucleotides twisted into a double helix, with four different bases: A, T, C and G.
Starch and cellulose are both made from glucose. Give the function of each in plants.
Mark scheme
- starch: energy store (1)
- cellulose: cell walls / strength (1)
Model answer
Starch stores energy, and cellulose strengthens plant cell walls.
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