Punnett Square Practice

Multiple Choice

Letters B, b, BB, Bb, bb

• Homozygous

• Heterozygous

• Hybrid

• Alleles

Punnett Squares

Originally designed by Reginald Punnett

How to draw a Punnett Square...

• Find the genotype for each parent.

• Draw a 2 x 2 square

• The male parent goes at the top.

• The female parent goes along the left side.

• Bring the male letters down.

• Bring the female letters across.

Remember for a recessive trait to be expressed, both genes must be recessive.

All recessive traits would come from homozygous alleles.

Fill in the Blanks

Fill in the Blanks

Multiple Choice

What is the probability of heterozygous offspring?

• 0%

• 100%

• 50%

• 25%

Fill in the Blanks

Multiple Choice

A trait that covers up another trait, represented by capital letter--B

• Dominant

• Recessive

• Hybrid

• Allele

Multiple Choice

A trait that gets covered up, represented by a lower case letter--b

• Dominant

• Recessive

• Hybrid

• Allele

Multiple Choice

Genetic makeup of an organism, represented by letters--BB, Bb, bb

• Genotype

• Phenotype

• Dominant

• Recessive

Multiple Choice

Both letters are the same--BB, bb

• Homozygous

• Heterozygous

• Homozygous Dominant

• Homozygous Recessive

Multiple Choice

Different alleles for a trait--Bb

• Homozygous Dominant

• Homozygous Recessive

• Heterozygous

• Recessive

Multiple Choice

Physical appearance, how it looks--Black, brown

• Genotype

• Phenotype

• Dominant

• Recessive

Multiple Choice

What you see, or the physical appearance.

• Genotype
• Phenotype
• Homozygous
• Heterozygous

Multiple Choice

Each one of the boxes on the Punnett Square represents what probability of an offsprings' genotype?

• 25%
• 1%
• 10%
• 0%

Multiple Choice

B = brown fur b = white fur

In the Punnett square, what is the probability for white fur?

• 0%

• 25%

• 50%

• 75%

Multiple Choice

In a certain species of plant, the color purple (P) is dominant to the color white (p).

According to the Punnett Square, what is the probability of an offspring being purple?

• 25%

• 0%

• 100%

• 50%

Multiple Choice

Brown eyes are dominant (B). Blue eyes are recessive (b). If 2 siblings' genotypes are (BB) and (Bb), will they have the same eye color (phenotype)?

• Yes, because they have the same genotype

• Yes, because the dominant trait is always expressed

• No, because they have different genotypes

• No, because the recessive trait has to be expressed