State Mendel’s law of independent assortment.

(i) A homozygous tall plant (T) bearing red (R) flowers is crossed with a homozygous dwarf plant (t) bearing white flowers (r):

1) Give the genotype and phenotype of the F1 generation.

2) Give the possible combinations of the gametes which can be obtained from the F1 hybrid.

3) Give the dihybrid ratio and the phenotype of the offspring of the F2 generation when two plants of the F1 generation above are crossed. 

52.

The diagram given below represents a stage during mitotic cell division in an animal cell. 

(i) Identify the stage. Give a reason to support your answer.

(ii) Name the parts labelled 1, 2 and 3.

(iii)What is the chromosome number of the cell?

(iv)Draw a neat, labelled diagram of the cell as it would appear in the next stage. Name the stage. 

Give reasons for the following:

(i) Plants begin to die when excess of soluble fertilisers are added to the soil.

(ii) Injury to the medulla oblongata results in death.

(iii)Gametes have a haploid number of chromosomes.

(iv)Green leaves are thin and broad.

(v) Lysosomes are termed suicidal bags of a cell.