4. The diagram shows the process of DNA replication.
[VISUALIZATION: Diagram showing a DNA double helix unwinding. One strand is labelled ‘Template strand’. Free nucleotides (A, T, C, G) are shown nearby. An enzyme (labelled DNA polymerase) is shown moving along the template strand, adding complementary nucleotides to form a new strand. Show base pairing A-T and C-G between the template and new strand. Indicate the direction of synthesis on the new strand with an arrow.]
(a) Identify the enzyme labelled DNA polymerase. [1]
(b) Explain the role of complementary base pairing in DNA replication. [3]
(c) Distinguish between DNA replication in prokaryotes and eukaryotes regarding the structure of the DNA molecule involved. [2]
Question
Identify the enzyme labelled DNA polymerase. [1]
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Look at the label on the enzyme in the diagram that is adding nucleotides.
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DNA polymerase
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Explain the role of complementary base pairing in DNA replication. [3]
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Think about how the sequence of one strand determines the sequence of the new strand. Which bases pair together?
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Ensures the new DNA strand is complementary to the template strand (A pairs with T, C pairs with G), maintaining the genetic code and resulting in identical DNA molecules.
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Distinguish between DNA replication in prokaryotes and eukaryotes regarding the structure of the DNA molecule involved. [2]
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Consider the shape of the DNA molecule and whether it is associated with proteins in each type of cell.
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Prokaryotic DNA is circular and typically lacks histone proteins (naked), while eukaryotic DNA is linear and associated with histone proteins.
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