Question 1

Which of the following best describes aneuploidy?

Accepted Answer

A condition in which one or more chromosomes are present in abnormal numbers, but not entire sets.

Question 2

A human cell with a karyotype of 2n-1 is best described as:

Accepted Answer

Monosomic

Question 3

Which of the following is the most common human autosomal aneuploidy that survives to birth?

Accepted Answer

Trisomy 21

Question 4

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

Accepted Answer

$$28$$

Question 5

Which of the following statements about polyploidy is TRUE?

Accepted Answer

Polyploidy is usually lethal in animals but often tolerated in plants.

Question 6

A person with Turner syndrome has a karyotype of 45,X. This is an example of:

Accepted Answer

Monosomy

Question 7

Which of the following best explains why even-numbered polyploids are more likely to be fertile than odd-numbered polyploids?

Accepted Answer

They can form homologous pairs during meiosis, allowing for balanced gametes.

Question 8

Which of the following is a likely consequence of nondisjunction during meiosis I in humans?

Accepted Answer

Half the gametes will have an extra chromosome, and half will be missing one.

Question 9

A Robertsonian translocation involves:

Accepted Answer

The fusion of two acrocentric chromosomes to form a single chromosome.

Question 10

Which of the following best defines endopolyploidy?

Accepted Answer

A condition in which only certain cells in an otherwise diploid organism are polyploid.

Question 11

Which of the following is a direct result of aneuploidy in humans?

Accepted Answer

Down syndrome

Question 12

If a wheat species is hexaploid (6N) and has a base chromosome number of 7, how many chromosomes are present in its somatic cells?

Accepted Answer

$$42$$

Question 13

Which of the following is NOT a typical consequence of polyploidy in plants?

Accepted Answer

Decreased genetic diversity

Question 14

A diploid organism has a chromosome number of $$2n = 16. If a $$nondisjunction event occurs during meiosis II, what is the possible chromosome number in the resulting gametes?

Accepted Answer

$$9 or$$ $$7$$

Question 15

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

Accepted Answer

Autopolyploidy involves duplication of chromosomes from a single species, while allopolyploidy involves combining chromosomes from different species.

Question 16

Which of the following is a reason why trisomy is more common than monosomy in live births?

Accepted Answer

Trisomy is less likely to disrupt gene balance than monosomy.

Question 17

A plant breeder crosses two diploid species (2n=14 and 2n=16) and then doubles the chromosome number in the hybrid. What is the chromosome number of the resulting allopolyploid?

Accepted Answer

$$30$$

Question 18

Which of the following is a likely outcome of a translocation involving chromosome 21 in a human carrier?

Accepted Answer

Increased risk of producing offspring with Down syndrome

Question 19

Which of the following best describes a sexually sterile polyploid?

Accepted Answer

Incapable of producing gametes with a complete set of chromosomes

Question 20

Which of the following is a common feature of Down syndrome, Turner syndrome, and Klinefelter syndrome?

Accepted Answer

All are forms of aneuploidy

Chromosomal Variations and Aneuploidy in Genetics

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