Q: In a pod with 8 seeds from a $$Gg \times Gg$$ cross, what is the probability of finding exactly 4 green seeds? (Assume $$p = \frac{3}{4}$$ for yellow, $$q = \frac{1}{4}$$ for green)

$$70 \times (\frac{3}{4})^4$ \times (\frac{1}{4})^4$

Question 1

In a dihybrid cross between two heterozygous pea plants (RrYy x RrYy), what is the probability that an offspring will be homozygous recessive for both traits?

Accepted Answer

$$\frac{1}{16}$$

Question 2

Which of the following best describes Mendel’s Law of Independent Assortment?

Accepted Answer

Alleles for different traits segregate independently during gamete formation.

Question 3

In chickens, the dominant allele $$Cr$$ produces the creeper phenotype, but $$CrCr is $$lethal. If two creepers ($$Crcr) $$are mated, what proportion of the living progeny will be creepers?

Accepted Answer

$$\frac{2}{3}$$

Question 4

A plant with genotype $$ssYy is $$crossed with a plant with genotype $$SsYy. $$What is the probability that an offspring will be heterozygous for both traits?

Accepted Answer

$$\frac{1}{4}$$

Question 5

Which rule of probability should be used to calculate the probability of two independent events both occurring?

Accepted Answer

Product rule

Question 6

In a cross between two $$BbCc$$ dogs, what fraction of the offspring will have black coat color and straight fur? ($$B = $$black, $$b = $$yellow, $$C = $$straight, $$c = $$curly)

Accepted Answer

$$\frac{9}{16}$$

Question 7

If you flip a fair coin three times, what is the probability of getting exactly two heads?

Accepted Answer

$$\frac{3}{8}$$

Question 8

For the cross $$Gg 	imes Gg$$, what is the probability that a yellow-seeded progeny is heterozygous?

Accepted Answer

$$\frac{2}{3}$$

Question 9

In a pod with 8 seeds from a $$Gg 	imes Gg$$ cross, what is the probability of finding exactly 4 green seeds? (Assume $$p = \frac{3}{4}$$ for yellow, $$q = \frac{1}{4}$$ for green)

Accepted Answer

$$70 	imes (\frac{3}{4})^4$ 	imes (\frac{1}{4})^4$

Question 10

Which formula represents the binomial probability of getting exactly $$k$$ successes in $$n$$ trials, where $$p is $$the probability of success?

Accepted Answer

$$P = \frac{n!}{k!(n-k)!} p^k q$$^{n-k}$$

Question 11

A family wants exactly 3 girls and 2 boys in 5 children. What is the probability of this outcome, assuming equal probability for each sex?

Accepted Answer

$$\frac{10}{32}$$

Question 12

Which of the following is true about the chi-square ($$\$$chi^2$$) test in genetics?

Accepted Answer

It evaluates whether observed data fit expected Mendelian ratios.

Question 13

Given the observed and expected values for a genetic cross, which formula is used to calculate the chi-square statistic?

Accepted Answer

$$\$$chi^2$$ = \sum \frac{(O - E)^2$}{E}$$

Question 14

In a pedigree analysis, which of the following is a prediction for an autosomal dominant trait?

Accepted Answer

Affected offspring must have at least one affected parent.

Question 15

If two individuals affected by an autosomal dominant trait have an unaffected child, what must be true about their genotypes?

Accepted Answer

Both parents are heterozygotes.

Question 16

Which of the following is NOT a prediction for an autosomal recessive trait in pedigree analysis?

Accepted Answer

Affected offspring must have at least one affected parent.

Question 17

In a chi-square test with 4 outcome classes, what are the degrees of freedom?

Accepted Answer

3

Question 18

A cross between $$RrGg x$$ $$RrGg$$ pea plants produces F2 offspring. What is the expected phenotypic ratio for round yellow : round green : wrinkled yellow : wrinkled green seeds?

Accepted Answer

9:3:3:1

Question 19

If the observed chi-square value for a genetic cross is much greater than the critical value for $$p = 0.05$$, what does this indicate?

Accepted Answer

The observed results are significantly different from the expected results.

Mendelian Inheritance: Dihybrid Crosses, Probability, and Pedigree Analysis

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