DNA and Genetics Review

B = brown eyes
b = blue eyes
What is true about these two brothers that have brown eyes?
One has genotype BB the other Bb.

• they have same phenotype and genotype
• they have different genotypes and phenotypes
• they have same phenotype but different genotypes
• they have same genotype but different phenotypes

If you have a parent who has GgBb as their genotype, what are the possible alleles they could donate to their gametes?

• GB, Gb, gB, gb
• GB, GB, gb, gb
• Gb, Gb, Gb, GB
• GG, BB, gg, bb

T4 - Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What percentage of the offspring of the cross BbTt x BBtt will have black fur and long tails?

• 0%
• 25%
• 50%
• 100%

T4 - What genotype is missing from this Punnett Square?

• RrYy
• RRYY
• rryy
• RrYY

In watermelons, green rinds (G) are dominant to striped rinds (g).  What is the genotype of a heterozygous green watermelon?

• GG
• Gg
• gg
• green

In cacti, long arms (A) are dominant to short arms (a).  Suppose 2 heterozygous cacti are crossed.  What percentage of their offspring are expected to have short arms?

• 0%
• 25%
• 75%
• 100%

A genotype is

• the listing of the alleles for the trait
• the physical appearance of the trait
• the separation of the chromosomes
• the letters seen on the outside of the Punnett square

When is a recessive gene expressed in the phenotype?

• when there are two different alleles of a gene

• when there are two identical alleles of a gene

• only in the absence of a dominant allele

• only in the absence of a recessive allele

A tomato plant has a genotype Wwgg. Select all possible genetic combinations that could be present in a single grain of pollen from this plant.

• wg

• WwGg

• Wg

• WG

• wwgg

E = brown eyes

e = blue eyes

What is true about these two brothers?

One has genotype Ee the other ee.

• they have same phenotype and genotype

• they have different genotypes and phenotypes

• they have same phenotype but different genotypes

• they have same genotype but different phenotypes