Biology 9700 · AS & A Level · Structure of nucleic acids and replication of DNA

Structure of nucleic acids and replication of DNA — practice question

Fig. 1.1 shows a photomicrograph of one area of eukaryotic tissue. Several of the cells are at mitotic stages.
(a(i))[2]

Identify the mitosis stage shown in cell E and in cell F in Fig. 1.1.

(a(ii))[1]

Microtubules are found inside cells that are undergoing mitosis, but they cannot be seen in Fig. 1.1. State the function of microtubules in mitosis.

(a(iii))[1]

State, with a reason, whether Fig. 1.1 shows animal tissue or plant tissue.

(b(A))[1]

The DNA double helix unwinds and is split into two template strands when ................................................ bonds holding the two strands together are broken.

(b(B))[1]

One template strand of DNA is copied in fragments. The enzyme ................................................ is needed to join the fragments into one continuous strand.

(b(C))[1]

Complementary DNA nucleotides are added to the template strands, with the reaction catalysed by the enzyme ................................................ .

(b(D))[1]

................................................ are regions of repeating nucleotide sequences at the ends of chromosomes that make it possible for DNA to keep replicating without genes being lost.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: E = metaphase.

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