genetics

Question 1

Explain what is meant by a recessive allele.

Question 2

Explain what is meant by codominant alleles.

Question 3

(i)
Explain one piece of evidence from the diagram which shows that the allele for Rhesus positive is dominant.

Question 4

Explain one piece of evidence from the diagram which shows that the gene is not on the X chromosome.

Question 5

What is meant by the term phenotype?

Question 6

A student investigated the monohybrid inheritance of eye shape in fruit flies. Two fruit flies with bar (narrow) eyes were crossed. Of the offspring, 1538 had bar eyes and 462 had round (normal) eyes.

(a) Using suitable symbols, give the genotypes of the parents. Explain your answer.

Question 7

The ratio of bar-eyed flies and round-eyed flies in the student’s results were not the same as the ratio she had expected.
What ratio of bar-eyed to round-eyed flies was the student expecting?

Question 8

Suggest two reasons why observed ratios are often not the same as expected ratios.

Question 9

The student wished to test her results with the ones she had expected.
Which statistical test should she use?