Question 1

Which of the following best describes the molecular structure of B-DNA as shown in the central model of the first image?

Accepted Answer

A right-handed double helix with 10 base pairs per turn and major and minor grooves.

Question 2

In the context of the chromosome diagram (second image), where would you most likely find highly repetitive DNA sequences?

Accepted Answer

At the telomeres and centromere.

Question 3

A woman with normal color vision has a father who is red-green colorblind (an X-linked recessive trait). If she has children with a man who also has normal color vision, what is the probability that their sons will be colorblind?

Accepted Answer

$$0.5$$

Question 4

Which of the following statements about the major and minor grooves of DNA is correct?

Accepted Answer

They are important because DNA-binding proteins often recognize specific base sequences by interacting with the major groove.

Question 5

If two pink-flowered 4 o’clock plants (incomplete dominance, $$R_1R_2) $$are crossed, what is the expected phenotypic ratio among 100 offspring?

Accepted Answer

25 red : 50 pink : 25 white

Question 6

Which of the following best explains why Y0 individuals (with only a Y chromosome) are never encountered in humans?

Accepted Answer

The Y chromosome lacks essential genes required for survival.

Question 7

A mating between two sphinx cats (KTR(hr)/KTR(hr)) is performed. What phenotypes can their offspring have?

Accepted Answer

All offspring will be sphinx.

Question 8

Which of the following is a loss-of-function mutation?

Accepted Answer

A mutation that results in a nonfunctional protein product.

Question 9

If two Manx cats (M/m) are bred, what is the expected phenotypic ratio among their kittens?

Accepted Answer

$$2$$ Manx : $$1$$ normal tail

Question 10

Which of the following best describes the genome of a typical eukaryotic cell?

Accepted Answer

DNA, double stranded, antiparallel, $$(A+G)/(T+C) = 1.0$$

Question 11

Which virus from the following base composition data most likely has a double-stranded DNA genome?

Accepted Answer

Herpes simplex: C = 33.4%, A = 16.3%, G = 33.6%, T = 16.7%

Question 12

Which of the following is true about the arrangement of genes A and B if they are on the same chromosome but assort independently?

Accepted Answer

They are far apart on the chromosome, allowing for frequent crossing over.

Question 13

What would be the complementary DNA sequence (5' to 3') for the following template: 5'-CCTTAAGG-3'?

Accepted Answer

Question 14

Which chromosomal feature is most directly impacted by the deletion of all MARs (matrix attachment regions)?

Accepted Answer

The formation of chromatin loops and higher-order chromosomal condensation.

Question 15

Which of the following best describes a nucleosome?

Accepted Answer

A segment of DNA wrapped around a core of histone proteins.

Question 16

Which of the following statements about intergenic regions is incorrect?

Accepted Answer

They are just spacers with no function between genes.

Question 17

A child has type B blood. The mother is type A and the alleged father is type O. What is the most likely explanation?

Accepted Answer

The alleged father cannot be the biological father of the child.

Question 18

Which of the following best describes a pseudoautosomal allele?

Accepted Answer

An allele located in a region of the sex chromosomes that can recombine with the homologous region on the other sex chromosome.

Question 19

Which of the following is a real-world example of a holandric gene?

Accepted Answer

A gene located on the Y chromosome that determines male-specific traits.

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