Genetics

Vocabulary flashcards based on lecture notes about genetics.

Gamete

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

Chromosome

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

Gene

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

Alleles

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

Dominant allele

Only one (out of the two alleles) is needed for it to be expressed and for the corresponding phenotype to be observed.

Recessive allele

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

Homozygous

When both inherited alleles are the same (i.e. two dominant alleles or two recessive alleles).

Heterozygous

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

Genotype

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

Phenotype

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

Zygote

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