Genetics: overview

Question 1

Define genes

Answer 1

A gene is a unit of heredity, a region of DNA that encodes a specific trait or function, e.g. a gene for eye colour. (very big generalisation) approx. 20-25,000 genes

Question 2

Define alleles

Answer 2

Alleles are different forms of the genes

• Trait controlled by recessive alleles - only be expressed if all chromosomes in a pair has it.
• Trait controlled by a dominant allele will be expressed if at least one chromosome has it

Question 3

Define heredity

Answer 3

passing of physical and behavioural characteristics from one generation to the next

Question 4

Define genotype

Answer 4

actual set of genes, DNA that we have inherited (guide)

Question 5

Define phenotype

Answer 5

the way that our genes manifest in our appearance and behaviours (expression)