Practise DNA and other naturally occurring polymers. 12 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Give the name of the shape of a DNA molecule.
Double helix
Starch and cellulose are also naturally occurring polymers. Name the monomer used to make both starch and cellulose.
Glucose (a sugar)
Name the monomers that join together to make proteins.
Amino acids
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
(a) What are the monomers of starch? Tick (✓) one box.[1]
Sugars (glucose)
Amino acids
Nucleotides
Alkenes
(b) What are the monomers of proteins? Tick (✓) one box.[1]
Sugars
Amino acids
Nucleotides
Esters
(c) What are the monomers of DNA? Tick (✓) one box.[1]
Sugars
Amino acids
Nucleotides
Alkanes
(d) Give the name of the shape of a DNA molecule.[1]
Show the answer and mark scheme
(a)Answer: Sugars (glucose)
(b)Answer: Amino acids
(c)Answer: Nucleotides
(d)Answer: Double helix
double helix
Question 2Medium5 marks
DNA (deoxyribonucleic acid) is a large molecule that is essential for life.
(a) Describe the structure of a DNA molecule.[3]
(b) What is the function of DNA?[1]
(c) Starch and cellulose are also naturally occurring polymers. Name the monomer used to make both starch and cellulose.[1]
Show the answer and mark scheme
(a)Answer: Two polymer chains made from four different nucleotides, twisted into a double helix.
two polymer chains
made from four different monomers called nucleotides
in the form of a double helix
(b)Answer: It encodes the genetic instructions for the development and functioning of living organisms and viruses.
it encodes genetic instructions (for the development and functioning of living organisms and viruses)
(c)Answer: Glucose (a sugar)
glucose / a sugar
Question 3Hard6 marks
Starch is a condensation polymer made from glucose, C6H12O6. One molecule of water is released for each glucose molecule that joins the chain. Relative formula masses (Mr): C6H12O6 = 180 H2O = 18
(a) Show that the relative formula mass of the repeating unit in starch is 162.[1]
(b) A starch molecule has a relative formula mass of 810 000. Estimate the number of glucose units in the molecule.[1]
(c) Calculate the mass of glucose formed when 16.2 g of starch is completely broken down into glucose.[2]
(d) Starch and cellulose are both made from a single type of monomer, but DNA is not. Explain this difference.[2]
Show the answer and mark scheme
(a)Answer: 180 − 18 = 162
180 − 18 = 162
(b)Answer: 5000
5000
(c)Answer: 18.0 g
16.2 ÷ 162 = 0.100 (mol of glucose units)
0.100 × 180 = 18.0 (g)
(d)Answer: Starch and cellulose are made only from glucose, but DNA is made from four different nucleotides.
starch and cellulose are made from only one type of monomer (glucose)
DNA is made from four different monomers (nucleotides)