topic 3

Question 1

gamete

Answer 1

An organism’s reproductive cell (egg in female and sperm in males), which has half the number of chromosomes (23).

Question 2

chromosome

Answer 2

A structure found in the nucleus which is made up of a long strand of DNA.

Question 3

gene

Answer 3

A short section of DNA that codes for a protein, and therefore contribute to a characteristic.

Question 4

alleles

Answer 4

The different forms of the gene - humans have two alleles for each gene as they inherit one from each parent.

Question 5

recessive allele

Answer 5

Two copies are needed for it to be expressed and for the corresponding the phenotype to be observed.

Question 6

homozygous

Answer 6

When both inherited alleles are the same

Question 7

heterozygous

Answer 7

When one of the inherited alleles is dominant and the other is recessive.

Question 8

genotype

Answer 8

The combination of alleles an individual has, e.g. Aa

Question 9

phenotype

Answer 9

The physical characteristics that are observed in the individual, e.g. eye colour

Question 10

zygote

Answer 10

The stage of development immediately after fertilisation - a diploid (2n) cell formed from the fusion of two haploid gametes