Question 1

Which of the following best describes the principle underlying chromosomal mapping?

Accepted Answer

Crossing over frequency

Question 2

If two genes are 10 map units apart on a chromosome, what does this indicate?

Accepted Answer

There is a less chance of recombination between them

Question 3

The SRY gene, which is crucial for male development in humans, is located on which chromosome?

Accepted Answer

Y chromosome

Question 4

In Drosophila, sex determination depends on which of the following?

Accepted Answer

Ratio of X chromosomes to sets of autosomes

Question 5

Which of the following statements about crossing over during meiosis is correct?

Accepted Answer

Crossing over occurs between non-sister chromatids

Question 6

A paracentric inversion differs from a pericentric inversion in that:

Accepted Answer

It does not include the centromere

Question 7

Which chromosomal mutation is most likely to result in a gene dosage effect due to extra copies of a gene?

Accepted Answer

Duplication

Question 8

A human cell with 47 chromosomes, including three copies of chromosome 21, is best described as:

Accepted Answer

Trisomic

Question 9

Which of the following is a likely consequence of a terminal deletion on a chromosome?

Accepted Answer

Loss of essential genes at the end of the chromosome

Question 10

Which chromosomal abnormality is most commonly associated with Chronic Myelogenous Leukemia (CML)?

Accepted Answer

Translocation between chromosomes 9 and 22

Question 11

Which of the following best describes aneuploidy?

Accepted Answer

A cell with one or more missing or extra chromosomes

Question 12

Polyploidy is most commonly observed in which group of organisms, and what is a typical consequence?

Accepted Answer

Plants; larger fruit size

Question 13

Which of the following is NOT a structural chromosomal mutation?

Accepted Answer

Aneuploidy

Question 14

A patient is diagnosed with Turner syndrome. Which chromosomal constitution is most likely?

Accepted Answer

$$45,X$$

Question 15

Which of the following best explains why most human autosomal monosomies are lethal?

Accepted Answer

The embryo has too low a dosage of essential gene products

Question 16

Which of the following is a likely result of nondisjunction during meiosis II in humans?

Accepted Answer

Half the gametes are normal, one is disomic, and one is nullisomic

Question 17

A plant species has a diploid number of $$2n=14. A $$tetraploid individual of this species would have how many chromosomes?

Accepted Answer

$$28$$

Question 18

Which of the following environmental factors is most likely to cause chromosomal breakage leading to mutations?

Accepted Answer

X-rays

Question 19

A geneticist observes a chromosome with a segment that has been reversed in orientation but does not include the centromere. What type of mutation is this?

Accepted Answer

Paracentric inversion

Question 20

Which of the following best describes the notation $$t(9;22)(q34;q11) in $$the context of CML?

Accepted Answer

A translocation between chromosome 9 at q34 and chromosome 22 at q11

Chromosome Mutations: Variation in Number and Arrangement

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