Genetics Test

Segments of DNA that code for traits are called ....

• genes

• proteins

• alleles

The physical expression of a trait is called the ...

• genotype

• phenotype

Genotype: TT

• homozygous dominant

• homozygous recessive

• heterozygous dominant

Genotype: Aa

• homozygous dominant

• homozygous recessive

• heterozygous dominant

Cross 2 heterozygous tall pea plants. Tall (T) is dominant to short (t). What fraction of the offspring do you predict will be tall?

• 1/4

• 2/4

• 3/4

• 4/4

In pea plants, tall (T) is dominant over short (t). If two heterozygous tall pea plants are mated, what is the the expected genotypic ratio of their offspring?

• 3 tall : 1 short

• 1 TT : 2 Tt : 1 tt

The different forms or versions of a gene are called ...

• alleles

• gametes

Having freckles is a dominant trait in humans.  A girl has freckles, but her brother does not. What do we know for certain about the parents?

• both parents have at least one recessive allele

• both parents are heterozygous for freckles

• one of the parents does not have freckles

this image is an example of

• codominance
• dominance
• incomplete dominance

A breed of chicken shows codominance for feather color. One allele codes for black feathers, another codes for white feathers. The feathers of heterozygous chickens of this breed will be:

• all black
• all white
• all gray
• speckled black and white