Monohybrid Cross Practice (Punnett Squares)

Front

What is the genotype of a heterozygous green watermelon?

Back

Gg

Answer explanation

Correct! Heterozygous genotypes have one dominant and one recessive trait. In this case, that would be Gg.

Front

One of the two forms of a gene is called a(n)

Back

allele

Answer explanation

Correct! Alleles are a version of a gene. For example, if there was a gene that coded for hair color, versions (alleles) of that gene could be brown, black, red, blonde, etc

Front

When a person has two different alleles for a gene, they are said to be

Back

heterozygous

Front

Aa, DD, Bb, yy are all examples of

Back

genotypes

Answer explanation

Correct! Genotypes are the genes an organism has that help code for proteins giving the phenotype (physical expression of the trait)

Front

T - tall and t = short In the punnett square below, what belongs in the missing square Options: tt, Tt, Bb, TT

Back

TT

Answer explanation

Correct! One parent gives a t in their gamete, and the other parent does as well, giving the genotype tt in the offspring.

Front

Which of the following is a phenotype?
Options: Aa, red hair, heterozygous, DNA

Back

red hair

Answer explanation

Correct! Red hair is the physical expression of a gene. Aa is a genotype, while heterozygous is a word describing the genotype alleles. DNA is where genes are stored.

Front

Which of the following genotypes is homozygous dominant? Options: A, Aa, AA, aa

Back

AA

Answer explanation

Correct! Homozygous refers to alleles that are the same. But dominant tells us that the alleles are both the dominant trait (represented by a capital letter)

Front

Which of the following genotypes is heterozygous? Options: Bb, BB, bb, B

Back

Bb

Front

What are the possible genotypes for this cross?

Back

TT = 25% Tt= 50% tt=25%

Answer explanation

Correct!

For the offspring of two parents with genotypes Tt x Tt:

1/4 or 25% are TT

1/2 or 50% are Tt

1/4 or 25% are tt

Front

If a homozygous dominant allele (AA) is crossed with a homozygous recessive allele (aa), all of the resulting offspring will be

Back

Heterozygous

Answer explanation

Correct! Each parent only has one allele in their gametes to share (AA x aa) and as a result all offspring are heterozygous (Aa)