Q: A couple are both carriers for cystic fibrosis (genotype Ff). What is the probability that, in four children, exactly three will be unaffected and one will be affected? Use the binomial theorem.

$$\left( \frac{3}{4} \$$right)^3$$ \times \left( \frac{1}{4} \right) \times 4 = 0.105$$

Question 1

Which of the following best describes the outcome of mitosis in terms of chromosome number?

Accepted Answer

It produces two diploid cells from one diploid cell.

Question 2

In Mendel’s monohybrid cross between true-breeding purple-flowered and white-flowered pea plants, what was the phenotypic ratio observed in the F2 generation?

Accepted Answer

$$3:1$$

Question 3

Which of the following statements about Mendel’s Law of Segregation is correct?

Accepted Answer

Each gamete receives only one allele from each gene pair, and which one is received is random.

Question 4

A couple are both carriers for cystic fibrosis (genotype Ff). What is the probability that, in four children, exactly three will be unaffected and one will be affected? Use the binomial theorem.

Accepted Answer

$$\left( \frac{3}{4} \$$right)^3$$ 	imes \left( \frac{1}{4} ight) 	imes 4 = 0.105$$

Question 5

Which of the following is NOT a reason why Mendel’s choice of pea plants was ideal for his experiments?

Accepted Answer

They have a long generation time.

Question 6

If a plant with genotype Ww (purple flowers) is test-crossed with a plant with genotype ww (white flowers), what is the expected phenotypic ratio among the offspring?

Accepted Answer

$$1$$ purple : $$1$$ white

Question 7

Which of the following best explains the Law of Independent Assortment?

Accepted Answer

Alleles for different genes assort independently if they are on different chromosomes.

Question 8

A dihybrid cross between two heterozygous pea plants (YyRr x YyRr) produces which phenotypic ratio in the F2 generation?

Accepted Answer

$$9:3:3:1$$

Question 9

Which of the following is the correct formula for the probability of obtaining exactly $$k$$ successes in $$n$$ independent trials, each with probability $$p of $$success (binomial theorem)?

Accepted Answer

$$P = \frac{n!}{k!(n-k)!} p^k (1-p$$)^{n-k}$$

Question 10

In a chi-square test, what does a p-value greater than 0.05 indicate about the null hypothesis?

Accepted Answer

The observed deviation is likely due to chance, so the null hypothesis is not rejected.

Question 11

Which of the following is a key feature of autosomal recessive inheritance in a pedigree?

Accepted Answer

The trait often skips generations and appears equally in both sexes.

Question 12

A couple, both heterozygous for albinism (Aa), have a child. What is the probability that the child will be albino (aa)?

Accepted Answer

$$1/4$$

Question 13

Which of the following best describes the difference between spermatogenesis and oogenesis?

Accepted Answer

Spermatogenesis produces four spermatids; oogenesis produces one oocyte and two polar bodies.

Question 14

If the observed data from a monohybrid cross are 760 dominant and 240 recessive individuals (total 1000), what are the expected numbers for a 3:1 ratio?

Accepted Answer

Dominant: 750, Recessive: 250

Question 15

Which of the following is true regarding the product law (multiplication rule) in probability?

Accepted Answer

It is used when two events must both occur together.

Question 16

In a trihybrid cross (AaBbCc x AaBbCc), how many different phenotypes are expected in the F2 generation, assuming simple dominance?

Accepted Answer

8

Question 17

Which of the following best explains why loss-of-function alleles are often recessive?

Accepted Answer

One functional allele is usually sufficient to produce the normal phenotype.

Question 18

A pedigree shows a trait that appears in every generation and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 19

If the probability of a child being male is $$1/2$$, what is the probability that in a family of three children, exactly one will be male and two will be female?

Accepted Answer

$$3/8$$

Mendelian Genetics: Principles, Probability, and Pedigree Analysis

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