Biology 9700 · AS & A Level · Testing for biological molecules

Testing for biological molecules — practice question

Meristematic tissue occurs in plant growth regions, such as root tips.
(a)

Fig. 4.1 shows a summary of the cell cycle in a meristematic cell from the root tip. The two phases of this cell cycle are: - interphase, split into the $G_1$, $S$ and $G_2$ stages - cell division, split into stages $1$-$5$

(a(i))[3]

In Fig. 4.1, stage $2$ is metaphase. The stages shown in Fig. 4.1 are listed below. Draw a circle around the stage in the cell cycle that is cytokinesis and describe what happens during this stage in the root tip meristematic cell.

(a(ii))[3]

The stages shown in Fig. 4.1 are listed below. Draw a circle around the stage in the cell cycle where the semi-conservative replication of DNA takes place and state what is meant by semi-conservative replication.

(b)[3]

Meristematic cells perform a role similar to that of stem cells in animals. Suggest the role of a meristematic cell and explain the features that enable it to carry out this role.

(c(i))[1]

Meristematic regions in the plant may sometimes be described as strong sinks. State what is meant by a sink.

(c(ii))[1]

Suggest the meaning of a strong sink.

(d)[4]

Describe and explain the process by which sucrose is loaded into phloem sieve tubes.

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