Question 1

Which of the following best describes a paracentric inversion?

Accepted Answer

An inversion that does not include the centromere.

Question 2

A diploid plant species has $$2n = 14$$ chromosomes. How many chromosomes would you expect in a trisomic individual of this species?

Accepted Answer

$$15$$

Question 3

Which of the following is a likely consequence of a chromosome deletion that removes the centromere?

Accepted Answer

The chromosome will be lost during cell division.

Question 4

A patient is diagnosed with Charcot-Marie-Tooth disease, which is associated with a duplication of the PMP22 gene. What is the most likely molecular mechanism underlying this disease?

Accepted Answer

An increase in gene dosage resulting in abnormal myelin sheath formation.

Question 5

Which of the following chromosomal mutations is most likely to result in pseudodominance?

Accepted Answer

Deletion

Question 6

A chromosome with the segments $$AB\cdot CDEFG is $$mutated to $$AB\cdot CDEFDEFG. $$Which type of chromosomal rearrangement has occurred?

Accepted Answer

Displaced duplication

Question 7

Which of the following statements about Robertsonian translocations is correct?

Accepted Answer

They result from the exchange of segments between two acrocentric chromosomes, producing one large metacentric chromosome and a small fragment.

Question 8

A human cell is found to have 47 chromosomes, including three copies of chromosome 21. Which condition does this describe?

Accepted Answer

Down syndrome (trisomy 21)

Question 9

Which of the following is NOT a typical effect of chromosomal duplications?

Accepted Answer

Loss of the duplicated region during meiosis.

Question 10

A plant breeder wants to create a new variety of wheat with increased chromosome sets for greater yield. Which chromosomal variation is most likely being utilized?

Accepted Answer

Polyploidy

Question 11

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

Accepted Answer

Monosomy leads to gene dosage imbalance and unmasking of deleterious recessive alleles.

Question 12

A chromosome with two centromeres is called a:

Accepted Answer

Dicentric chromatid

Question 13

Which of the following is a common cause of aneuploidy in humans?

Accepted Answer

Nondisjunction during meiosis

Question 14

A diploid organism has $$2n = 56$$ chromosomes. How many chromosomes would be present in a tetrasomic individual?

Accepted Answer

$$58$$

Question 15

Which of the following is a real-world example of a beneficial polyploidy event in agriculture?

Accepted Answer

The creation of seedless watermelons (triploid)

Question 16

Which of the following is NOT a possible effect of a chromosomal translocation?

Accepted Answer

Increase in the number of centromeres per chromosome

Question 17

A plant species I is diploid with $$2n = 4 ($$AABB), and species II is diploid with $$2n = 6 ($$MMNN). What would be the chromosome number in an allotetraploid formed from both species?

Accepted Answer

$$2n = 10$$

Question 18

Which of the following best describes the difference between autopolyploidy and allopolyploidy?

Accepted Answer

Autopolyploidy involves chromosome sets from a single species, while allopolyploidy involves chromosome sets from two or more species.

Question 19

Which of the following is NOT a way that deletions can cause abnormal phenotypes?

Accepted Answer

Haploinsufficient genes can result because too much gene product is produced.

Question 20

A strawberry plant is octoploid ($$8n). If $$the base chromosome number is $$n = 7$$, how many chromosomes are present in a somatic cell?

Accepted Answer

$$56$$

Chromosomal Variation: Rearrangements, Aneuploidy, and Polyploidy

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