Question 1

According to Mendel’s model, what is the expected phenotypic ratio in the F2 generation when two heterozygous pea plants (RrYy) are crossed, assuming independent assortment for seed shape (R = round, r = wrinkled) and seed color (Y = yellow, y = green)?

Accepted Answer

$$9:3:3:1 (9 $$round yellow : 3 round green : 3 wrinkled yellow : 1 wrinkled green)

Question 2

Which of the following best explains why genes located close together on the same chromosome tend to be inherited together?

Accepted Answer

They are linked and less likely to be separated by crossing over during meiosis.

Question 3

A woman with blood type AB ($$I^A I^B) $$and a man with blood type O ($$ii) $$have children. What are the possible blood types of their offspring?

Accepted Answer

A or B

Question 4

In a cross between a red-flowered four-o’clock plant ($$RR) $$and a white-flowered plant ($$rr$$), all F1 offspring have pink flowers. What type of inheritance does this demonstrate?

Accepted Answer

Incomplete dominance

Question 5

A pedigree shows a trait that appears in every generation, affects males and females equally, and unaffected individuals do not transmit the trait. What is the most likely mode of inheritance?

Accepted Answer

Autosomal dominant

Question 6

Which experimental result from the Hershey-Chase experiment provided evidence that DNA, not protein, is the genetic material?

Accepted Answer

Radioactive DNA was found inside the bacterial cells, while radioactive protein remained outside.

Question 7

If a carrier female for an X-linked recessive trait (e.g., red-green color blindness) has children with a normal male, what proportion of their sons are expected to be affected?

Accepted Answer

$$\frac{1}{2}$$

Question 8

Which of the following statements about semiconservative DNA replication is correct?

Accepted Answer

Each new DNA molecule consists of one parental strand and one newly synthesized strand.

Question 9

A geneticist observes that two genes in fruit flies recombine with a frequency of 36%. What does this indicate about the physical distance between these genes?

Accepted Answer

They are relatively far apart on the same chromosome.

Question 10

Which of the following best describes a multigenic (polygenic) trait?

Accepted Answer

A trait influenced by multiple genes, often showing continuous variation (e.g., human height).

Question 11

A man with type A blood ($$I^A i) $$and a woman with type B blood ($$I^B i) $$have a child. What is the probability that their child will have type O blood?

Accepted Answer

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

Question 12

Which of the following is a key feature of X-linked dominant inheritance?

Accepted Answer

All daughters of an affected father are affected, but no sons.

Question 13

If a gene is located on the X chromosome and is recessive, which of the following is true about its inheritance?

Accepted Answer

Males are more likely to express the trait because they have only one X chromosome.

Question 14

Which of the following best describes the principle of segregation as proposed by Mendel?

Accepted Answer

Each gamete receives only one allele of each gene.

Question 15

A cross between two heterozygous pea plants ($$Rr) $$results in which genotypic ratio among the offspring?

Accepted Answer

$$1:2:1 (RR$$ : Rr : rr)

Question 16

Which of the following is an example of codominance?

Accepted Answer

AB blood type, where both $$I^A$$ and $$I^B$$ alleles are expressed equally.

Question 17

Which of the following is NOT a claim made by Mendel in his model of inheritance?

Accepted Answer

Genes are always inherited in groups and never separate.

Question 18

If a trait is autosomal recessive, what is the probability that two carrier parents will have an affected child?

Accepted Answer

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

Question 19

Which of the following best explains why the actual distribution of human height approximates a bell-shaped curve?

Accepted Answer

Height is a polygenic trait influenced by multiple genes and environmental factors.

Mendelian Genetics and Extensions: Principles, Patterns, and Human Applications

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