Question

7. Draw a sexual life cycle. Explain how a typical plant life cycle is different from an animal life cycle. [4 marks) 8. Explain what happens when a molecule becomes phosphorylated. Give two examples of this process that we have discussed in class. [2 marks] 9. If a cell has 2 picograms of DNA at G1, then how much DNA will each of the daughter cells contain in metaphase Il of meiosis? Explain how you arrived at your answer. [2 marks]

Answer 1

7.Sexual life cycle of plant:

meiosis - sporophyle diploid (21) spoon Spores handloid (Syngamy) , haploid a zy gole excell Archegorienam Gametophyle hiyle male gamete An the rideum in An the rider (1h) Gamesto genesis)

Difference between animal and plant life cycle is in plant life cycle there is alternation of generation. In animal life cycle there is no alternation of generation.

In plants haploid gametophyte always alternates with diploid sporophyte stage.

In animals only the gametes are haploid. Once the two gamtes fuse a diploid zygote is formed which is diploid. The zygote formed may develop in to a diploid larva which may be free swimming. In some parasitic animal life cycles, there may be number of such free swimming forms till it reaches final host.

8. In G1 the DNA is 2 picograms. During S phase, the DNA becomes 4 pico grams. After first meiosis it becomes 2 picograms again because the daughter cells formed will have half the DNA content. When te daughter cell has entered in to meiosis 2 , in its metaphase, it will have 2 picograms in each cell.

2 picograms is the answer.