Cambridge International A Level Biology Revision Guide

Cambridge International A Level Biology
7 Diagram 1 shows chromosomes in the nucleus of a diploid cell.
1
a Draw the nucleus of a gamete produced from this cell. [1]
b What type of nuclear division would be used in the production of the gamete? [1]
c Draw a diagram to show what the nucleus would look like in anaphase of mitosis. [3]
Diagrams 2 and 3 below show the same diploid nucleus as in diagram 1. However, the chromosomes
have been shaded.
2 3
394
d State what the different types of shading represent in each nucleus. [2]
e Draw a karyogram based on the diploid nucleus shown in all three diagrams. [3]
[Total: 10]
8 There is no crossing over during meiosis in male Drosophila. Assuming that no mutation occurs, the only source
of genetic variation is independent assortment. Given that the diploid (2n) chromosome number is 8, calculate
the number of genetically different spermatozoa that can be produced. [1]
9 Distinguish between the following pairs of terms.
a genotype and phenotype [2]
b homozygous and heterozygous [2]
[Total: 4]