Monohybrid Cross Punnett Square

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

• GG

• Gg

• gg

• green

Answer explanation

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

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

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

• genotype

• allele

• hybrid

• trait

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

Tags

NGSS.HS-LS3-2

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

• heterozygous
• homozygous

Aa, DD, Bb, yy are all examples of

• genotypes

• phenotypes

Answer explanation

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

T - tall and t = short

In the punnett square below, what belongs in the missing square

• tt

• Tt

• Bb

• 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.

Tags

NGSS.HS-LS3-1

Which of the following is a phenotype?

• Aa

• red hair

• heterozygous

• DNA

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.

Which of the following genotypes is homozygous dominant?

• A

• Aa

• AA

• 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)

Which of the following genotypes is heterozygous?

• Bb
• BB
• bb
• B

What are the possible genotypes for this cross?

• TT = 25% Tt= 50% tt=25%

• all tall

• TT= 75% tt = 25%

• Tt = 100%

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

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

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

• Homozygous dominant

• Heterozygous

• Homozygous Recessive

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)

Tags

NGSS.HS-LS3-1