Genetics Review

Two brown eyed parents (Bb) have a baby. What is the chance the baby is blue eyed? (B=brown eyes and b=blue eyes)

• 0 %

• 25%

• 50%

• 75%

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-3

A red flower (Rr) is crossed with a white flower (rr). What is the genotypic ratio?

• 0 RR; 0 Rr: 4 rr

• 2 RR; 0 Rr: 2 rr

• 4 RR; 0 Rr: 0 rr

• 0 RR; 2 Rr: 2 rr

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Based on the results in the monohybrid punnett, what is the phenotypic ratio?

• 3:1

• 1:1

• 2:2

• 4:0

Tags

112.34.c.6.F

What ratio of the offspring from the cross shown will be recessive for the trait of tallness?

Dominant: AA or Aa

Recessive: aa

• 0 in 4

• 1 in 4

• 2 in 4

• 4 in 4

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

NGSS.HS-LS3-3

In guinea pigs, the allele for short hair is dominant. If all the guinea pigs are born short haired what are the possible genotypes of the parents? (There are two possible combinations.)

• Ss + Ss

• SS + SS

• SS + Ss

• ss + ss

Answer explanation

Correct! A cross of SS x SS would create babies with all SS genotypes and therefore all short haired.

A cross of SS x Ss would create babies that were 50% SS and 50% Ss, but all combinations have a dominant S trait, so they woulid still all have short hair!

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

The MC1R gene controls the color of melanin that the body produces. The gene shows dominant-recessive inheritance and typically has two alleles. The DOMINANT allele (E) produces animals with DARK FUR. The recessive allele (e) produces animals with red fur. A heterozygous dog (Ee) has eight black puppies. This means that the other parent was most likely... (a)  

• homozygous DOMINANT (EE)
• heterozygous (Ee)
• homozygous recessive (ee)

Tags

HS-LS3-3

Complete the following monohybrid punnett by labeling the each box with the correct genotype.

a

b

c

d

TT

Tt

tt

Tt

Tags

112.34.c.6.F

Select the boxes in the Punnett Square where you would find heterozygous offspring.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

Which box would represent homozygous recessive?

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2