Heredity: Multiple Choice Vocabulary Test

The genes for certain characteristics are (0)       D       passed down from parents to children. For example, parents with brown eyes often (1)________ birth to children with brown eyes.

(2)________ now and again, though, this doesn't work and parents with brown eyes can have a blue-eyed baby. This is explained by a(n) (3)________ called segregation.

Hereditary traits are (4)________ by specific genes and each individual carries two genes for each trait, one from each parent. When an individual reproduces, the two genes (5)________ up or segregate into the two types of male and female cells that join (6)________ to make a new individual.

Inherited characteristics come from (7)________ genes. There is a different gene for each (8)________ characteristic. There is a gene for height, a gene for hair colour, a gene for eye colour and so on. Variations of the gene for the same trait are (9)________ alleles.

In each gene (10)________ one of the two genes is dominant over the other. The dominant allele will hide the recessive allele. For example, if, the father gives a brown allele of the eye colour gene, and the mother gives a blue allele, the child will have brown eyes. This is why brown eye colour is dominant and blue is recessive. Sometimes two genes are co-dominant, as in the (11)________ of skin colour, for example. The child of a dark skinned person and a pale skinned person, therefore, will be a (12)________ of the two.