In pea plants, tall plants (T) are dominant over short plants (t). If a heterozygous tall pea plant is crossed with a homozygous recessive short pea plant, what percentage of the offspring is expected to be tall.

Question

(HINT: use a Punnett square to help you with this question)

(1 point)
Responses

0%
0%

50%
50%

75%
75%

25%

Answer 1

To determine the expected percentage of tall offspring when a heterozygous tall pea plant (Tt) is crossed with a homozygous recessive short pea plant (tt), we can use a Punnett square.

Here’s how the cross looks:

• Parent 1 (heterozygous tall): Tt
• Parent 2 (homozygous recessive short): tt

The Punnett square would look like this:

        T      t
      ----------------
    t |   Tt   |   tt   |
      ----------------
    t |   Tt   |   tt   |
      ----------------

From the square, we can see the possible genotypes of the offspring:

• Tt (tall) = 2 instances
• tt (short) = 2 instances

Thus, the expected genotypic ratio is:

• 2 Tt : 2 tt, which simplifies to 1 Tt : 1 tt.

This means 50% of the offspring are expected to be tall (Tt).

Therefore, the answer is 50%.

Answer 2

If a black chicken (BB) is crossed with a white chicken (WW) and incomplete dominance is observed, what are the expected phenotypes of the offspring?(1 point)
Responses

All gray
All gray

All black
All black

All white
All white

All red

Answer 3

In the case of incomplete dominance, when a black chicken (BB) is crossed with a white chicken (WW), the resulting offspring will show a blended phenotype rather than one of the parents' phenotypes.

For this cross:

• BB (black)
• WW (white)

The offspring will all inherit one allele from each parent, resulting in the genotype BW. Because of incomplete dominance, the phenotype associated with this genotype will not be entirely black or entirely white; instead, it will be a blend of the two.

Therefore, the expected phenotype of the offspring will be gray.

So the answer is: All gray.

Answer 4

In cattle, coat color is controlled by codominant alleles. A red-coated cow (RR) is crossed with a white-coated bull (WW). What are the expected phenotypes of the offspring?(1 point)
Responses

All pink coat
All pink coat

Red and white coat
Red and white coat

All red coat
All red coat

All white coat

Answer 5

In cattle, if coat color is controlled by codominant alleles, this means that both alleles are expressed equally in the phenotype when present together.

In the given scenario:

• A red-coated cow has the genotype RR.
• A white-coated bull has the genotype WW.

When these two are crossed (RR × WW), the resulting offspring will have the genotype RW.

In codominance, the offspring (RW) will display both traits distinctly. Therefore, the expected phenotypes of the offspring will be red and white coat colors.

So the answer is: Red and white coat.

Answer 6

Complete the mRNA sequence that will be formed from the DNA sequence below, then identify the amino acids using the codon chart provided above.

(6 points)
Put responses in the correct input to answer the question. Select a response, navigate to the desired input and insert the response. Responses can be selected and inserted using the space bar, enter key, left mouse button or touchpad. Responses can also be moved by dragging with a mouse.
TAC CGC CCC
mRNA Response area Response area Response area
Amino Acid Response area Response area Response area

Answer 7

To transcribe the DNA sequence into mRNA, you need to replace each DNA base with its complementary RNA base:

• Adenine (A) in DNA pairs with Uracil (U) in RNA.
• Thymine (T) in DNA pairs with Adenine (A) in RNA.
• Cytosine (C) in DNA pairs with Guanine (G) in RNA.
• Guanine (G) in DNA pairs with Cytosine (C) in RNA.

Given the DNA sequence:

• TAC CGC CCC

The corresponding mRNA sequence will be:

• AUG GCG GGG

Next, to identify the amino acids using the codon chart based on the mRNA sequence:

1. AUG - Methionine (Met) (this is often a start codon)
2. GCG - Alanine (Ala)
3. GGG - Glycine (Gly)

Final Responses:

mRNA:

• AUG
• GCG
• GGG

Amino Acids:

• Met
• Ala
• Gly

Feel free to fill in the responses in the designated response areas!

Answer 8

Use the codon chart below to determine the bases that will code for the amino acid Methionine (Met).

(1 point)
Uracil Cytosine Adenine Guanine
First Base

Second Base

Third Base

Answer 9

Methionine (Met) is coded by the codon AUG in mRNA. To determine the bases that correspond to each position of the codon, we can break it down as follows:

• First Base: A (Adenine)
• Second Base: U (Uracil)
• Third Base: G (Guanine)

So, using the codon chart to code for Methionine (Met), we have:

1. First Base: A
2. Second Base: U
3. Third Base: G

This corresponds to the mRNA codon AUG, which codes for Methionine.