Genetics questions | form four Biology

Colour blindness is a sex linked character controlled by a recessive gene located on the X-chromosome. Only homozygous females suffer from this condition. It is more common to males. What percentage will the males suffering from colour blindness be if a normal male marries a colour blind female?.

If one parent was homozygous tall (TT) and the other homozygous short (tt) what will the
genotype of the offspring be? Illustrate your answer.

Define the following terms:
(i) Phenotype.
(ii) Recessive.
(iii) Heterozygous

Study the pedigree below (Figure 4) and then answer the questions that follow.

Open figures indicate normal phenotypes; black figures indicate colour blind individuals.
(i) What is the probable genotype of 1?
(ii) Is the answer to (i) above 100% certam? Explain.
( iii) What is the genotype of 5 and 9?
(iv) Justify your answer in (iii) above.
(v) If 3 marries a normal man, what are the chances that she will have a colour blind son? Illustrate your answer.

Observe the punnet square below (figure 4).

The possible gene combinations in square number 3 of figure 4 above is

1. bcBc
2. bbCc
3. BbCc
4. Bbcc
5. bbcc

The number of chromosomes in a fertilized egg in man that will grow into  a male of child isa.

1. 22 pairs + XX
2. 22 pair s + XY
3. 22 pairs + y
4. 22 + XY.

In an experiment, bean seeds having a smooth seed coat were crossed with beans having wrinkled seed coat. All the seeds obtained in the first filial generation (F​ 1​ ) had a smooth seed coat. Use genetic cross to find out the formation of (F​ 1​ ) individuals.

What is variation as applied to genetics?
A Differences among individuals of the related species.
B Differences among individuals of the same species.
C Differences among individuals of different species.
D Differences among individuals of unrelated species.
E Differences among individuals of the expected species.

Why is the study of genetics important in our daily life? Explain by giving four points.

A newly married couple expects a baby. Using a genetic cross, work out the probability of their first born child being a boy.