Formative Practice 11.1 (Form 5 Biology Textbook Exercise and Answer)

Question 1:
What is meant by purebreed?

Purebreed means that the organism genotype is homozygous; whether it is homozygous dominant or homozygous recessive. The organism carries two similar alleles for each characteristic.

Question 2:
In a fertilisation between two rats, B represents dominant allele for black fur, whereas b represents recessive allele for white fur. If the outcome of fertilisation is ¼ BB : ½ Bb : ¼ bb, what are the fur colours and genotypes of their parents?

Both parents have black fur with Bb genotype.

Question 3:
Assume that an allele for a tall trait is represented by symbol T and allele for a dwarf trait is represented by symbol t. What are the genotypes and phenotypes of offsprings from a fertilisation between a tall plant and a dwarf plant in which both are purebreed?

All offsprings are tall (genotype) with Tt genotype.

Leave a Comment