Draw a short segment of a single polynucleotide strand, including at least three
nucleotides. Indicate the polarity of the strand by identifying the 5' end and the 3'
end.

The frequency of a recessive allele in a large randomly mating population is 0.2.
What is the frequency of:
(a) The dominant allele?
(b) The heterozygote?

What roles do the following play in cloning a DNA fragment?
(a) Restriction enzymes.
(b) Vectors.
(c) DNA ligase.
(d) Electroporation.

Use of twin studies.

In water melon, red fruit colour (R) is dominant over cream fruit colour (r). A water
melon plant homozygous for red fruits is crossed with a plant homozygous for
cream fruits. The F1 are intercrossed to produce F2.
(a) Give the genotypes and phenotypes of the parents, the F1, and the F2.
(b) Give the genotypes and phenotypes of the offspring of a backcross
between the F1, and the red fruit colour homozygous parent.
(c) Give the genotypes and phenotypes of a backcross between the F1, and the
cream fruit colour homozygous parent.

Describe the lac operon and how it controls the metabolism of lactose. Support
your answer with clear and well labelled diagrams.

Compare and contrast the following terms:
(a) Gene and allele.
(b) Genotype and phenotype.
(c) DNA and RNA.
(d) DNA and chromosome.
(e) Locus and allele.