Question

question 18 of 25

in banded snails, shell color is controlled by a gene with a dominant allele for brown color, \\(b\\), and a recessive allele for yellow color, \\(b\\). the presence of bands is controlled by a gene with a dominant allele that produces no bands, \\(u\\), and a recessive allele that produces five bands, \\(u\\). the two genes do not occur on the same chromosome. snails with the following genotypes are crossed:

\\(bbuu \times bbuu\\)

what is the probability that the offspring will have the \\(bbuu\\) genotype?

a. 0.25
b. 0.00
c. 0.50
d. 1.00

Explanation:

<pre_analysis>
{
"quality": "clear",
"question_count": 1,
"skills_matched": [
"step_cot",
"multiple_choice_formatter",
"explain_then_answer",
"tutor",
"mastery_adaptive_brevity"
],
"needs_drawing": false,
"concepts_used": [
"Dihybrid Cross",
"Independent Assortment"
],
"new_concepts": [],
"current_concepts": [
"Dihybrid Cross",
"Independent Assortment",
"Mendelian Genetics"
]
}
</pre_analysis>

<reasoning>

Analyze the parental genotypes

Using the Dihybrid Cross knowledge point
\[
\text{Parent 1: } BBUU \quad \times \quad \text{Parent 2: } Bbuu
\]

Determine allele segregation for the B gene

Using the Independent Assortment knowledge point
\[

$$\begin{aligned} &\text{Cross: } BB \times Bb \\ &\text{Offspring genotypes: } \frac{1}{2} BB, \ \frac{1}{2} Bb \\ &P(BB) = 0.50 \end{aligned}$$

\]

Determine allele segregation for the U gene

Using the Independent Assortment knowledge point
\[

$$\begin{aligned} &\text{Cross: } UU \times uu \\ &\text{Offspring genotypes: } 100\% \ Uu \\ &P(UU) = 0.00 \end{aligned}$$

\]

Calculate the probability of the BBUU genotype

Using the Independent Assortment and Dihybrid Cross knowledge points
\[

$$\begin{aligned} P(BBUU) &= P(BB) \times P(UU) \\ P(BBUU) &= 0.50 \times 0.00 = 0.00 \end{aligned}$$

\]
</reasoning>

<answer>
<mcq-option>A. 0.25</mcq-option>
<mcq-correct>B. 0.00</mcq-correct>
<mcq-option>C. 0.50</mcq-option>
<mcq-option>D. 1.00</mcq-option>
</answer>

<post_analysis>
{
"subject": "Natural Science",
"question_type": "Multiple Choice",
"knowledge_point": [
"Natural Science",
"Biology",
"Mendelian Genetics"
]
}
</post_analysis>

Answer:

<pre_analysis>
{
"quality": "clear",
"question_count": 1,
"skills_matched": [
"step_cot",
"multiple_choice_formatter",
"explain_then_answer",
"tutor",
"mastery_adaptive_brevity"
],
"needs_drawing": false,
"concepts_used": [
"Dihybrid Cross",
"Independent Assortment"
],
"new_concepts": [],
"current_concepts": [
"Dihybrid Cross",
"Independent Assortment",
"Mendelian Genetics"
]
}
</pre_analysis>

<reasoning>

Analyze the parental genotypes

Using the Dihybrid Cross knowledge point
\[
\text{Parent 1: } BBUU \quad \times \quad \text{Parent 2: } Bbuu
\]

Determine allele segregation for the B gene

Using the Independent Assortment knowledge point
\[

$$\begin{aligned} &\text{Cross: } BB \times Bb \\ &\text{Offspring genotypes: } \frac{1}{2} BB, \ \frac{1}{2} Bb \\ &P(BB) = 0.50 \end{aligned}$$

\]

Determine allele segregation for the U gene

Using the Independent Assortment knowledge point
\[

$$\begin{aligned} &\text{Cross: } UU \times uu \\ &\text{Offspring genotypes: } 100\% \ Uu \\ &P(UU) = 0.00 \end{aligned}$$

\]

Calculate the probability of the BBUU genotype

Using the Independent Assortment and Dihybrid Cross knowledge points
\[

$$\begin{aligned} P(BBUU) &= P(BB) \times P(UU) \\ P(BBUU) &= 0.50 \times 0.00 = 0.00 \end{aligned}$$

\]
</reasoning>

<answer>
<mcq-option>A. 0.25</mcq-option>
<mcq-correct>B. 0.00</mcq-correct>
<mcq-option>C. 0.50</mcq-option>
<mcq-option>D. 1.00</mcq-option>
</answer>

<post_analysis>
{
"subject": "Natural Science",
"question_type": "Multiple Choice",
"knowledge_point": [
"Natural Science",
"Biology",
"Mendelian Genetics"
]
}
</post_analysis>