HEREDITY

Question 1

What is an allele?

Answer 1

Alleles are different forms of the same gene. They occupy the same relative positions on a pair of homologous chromosomes.

Question 2

What is a genotype?

Answer 2

A genotype is the genetic make up of an organism (i.e the combination of genes)
A dominant allele is denoted as a capital letter e.g T
A recessive allele is denoted as a small letter e.g t

Question 3

What are the three combinations of genotypes?

Answer 3

TT- homozygous dominant
Tt- heterozygous dominant
tt- homozygous recessive

Question 4

What are some chemical mutagens?

Answer 4

Tar/Formaldehyde/LSD

Question 5

What are some radiation mutagens?

Answer 5

Ultraviolet light/alpha-beta-gamma radiation

Question 6

How does genetic variation lead to the rise of a new species?

Answer 6

Mutation occurs, giving rise to (organism) with the gene for (specified trait [ST]), which is advantageous for the (specified environment [SE]).
In a SE, Nature selects the organism with the ST as they are more adapted to the changes in the environment. Organisms with ST will survive to reproductive age and pass on the favourable allele to their offspring. As a result, the frequency of (ST) will increase in the population. As a result, the region will have more organisms with (ST). That organism becomes dominant in that environment.