Genetics

Genotype refers to the...

• physical expression of the genes.
• the possible combination of alleles in a gene.
• whether an allele is dominant or recessive.
• how an organism will appear.

What is a phenotype?

• The genetic code
• The physical trait

In a monohybrid cross an offspring will receive how many alleles from each parent to determine a specific trait?

• one
• two
• three
• five

Having two of the same genes for the trait (sometimes called purebred or true-breeding).

• homozygous
• hetrozygous
• protein
• chromosome

Having two different genes for a trait.

• hemizygous
• homozygous
• heterozygous
• genotype

y = green, Y = yellow
The genotype for a green plant is...

• YY
• Yy
• yy
• all of the choices result in yellow

Two heterozygous (Tt) tall pea plants are crossed. Which describes their offspring?

• 50% tall and 50% short
• 75%tall and 25% short
• 100%short
• 100% tall

Which answer best describes co-dominant alleles?

• Both are equally dominant
• Both are equally recessive
• Neither are dominant

A corn plant heterozygous for tall sprouts mates with a corn plant with short sprouts. If tall sprouts are dominant, how many different phenotypes are possible in the offspring?

• 1
• 2
• 3
• 4

If a heterozygous tall (Tt) pea plant is crossed with a short (tt) pea plant, what are the possible genotypes of the future offspring?

• 100% Tt
• 50% Tt, 50% tt
• 75%Tt, 25%tt
• 25%TT, 50%Tt, 25%tt