A diagrammatic representation of the cell cycle indicating the formation of two daughter cells from a parent cell is giVen above. Observe the diagram and answer the following questions.
(a) When does replication of DNA take place?
(b) The amount of DNA in G₁ phase is denoted as 2C and the chromosome number as 2n. Show
(i) the amount of DNA and
(ii) the chromosome number in prophase.
(c) Why is mitosis called equational division?

(a) Label the parts A, B, C and D in the diagram given above.
(b) Determine the stage and the event that is represented.

(a) Identify the stage and type of cell division.
(b) Write the two key features of this phase.
(c) Is it a plant cell or animal cell showing the process? Justify your answer.

Mitosis accomplishes not only the segregation of the duplicated chromosomes to daughter nuclei, but the cell itself divides into two daughter cells, by cytokinesis. In animal cells, cytokinesis occurs with the appearance of a furrow in the cell membrane that deepens and joins in the centre to divide the cell, but in plants it is different.
(a) Why cannot the plant cells divide the same way as animalcells?
(b) Name the precursor of cell walls in plant cells. What does it represent in the cell wall?
(c) What will be the consequence, if cytokinesis does not follow karyokinesis? Give an example.

Sexual reproduction involves fusion of two gametes, each with a complete haploid set of chromosomes. In animals, gametes are formed from specialised diploid cells. Meiosis ensures the production of haploid phase in the life cycle of sexually reproducing organisms and fertilisation restores the diploid phase.
(a) Mention the four key features of meiosis.
(b) Why does reduction in the number of chromosomes occur during meiosis?

Study the two stages of cell division in the given figure and answer the questions that follow:

(a) Identify the stage and the type of cell division in A and B.
(b) Write one major difference between the two.