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

Structure of nucleic acids and replication of DNA — practice question

Fig. 6.1 presents photomicrographs of separate cells from the onion root tip, $\textit{Allium sp.}$, taken at different points in the mitotic cell cycle.
(a(i))[1]

Arrange the letters for the individual cells into the correct sequence of the mitotic cell cycle. The first letter has already been given.

(a(ii))[2]

Cell A in Fig. 6.1 is in one of the main stages of mitosis. Describe what happens during this main stage of mitosis.

(b)[3]

Complete Table 6.1 by giving the term that fits each description: - DNA region with repeated nucleotide sequences at chromosome ends - structure that organises microtubules to make the spindle in animal cells - site where two sister chromatids are joined

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: Sequence in order: B, E, F, D, A, C

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