Question 1

Which of the following best describes aneuploidy?

Accepted Answer

A condition in which an organism has an abnormal number of a particular chromosome.

Question 2

A human cell with 47 chromosomes due to an extra chromosome 21 is an example of which chromosomal abnormality?

Accepted Answer

Trisomy

Question 3

Which chromosomal alteration is most likely to result in a gene dosage imbalance, potentially causing severe developmental disorders?

Accepted Answer

Duplication

Question 4

If a gamete with $$n+1$$ chromosomes fuses with a normal gamete, what will be the chromosome number of the resulting zygote?

Accepted Answer

$$2n+1$$

Question 5

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

Accepted Answer

One gamete will have an extra chromosome, one will be missing one, and two will be normal.

Question 6

Which chromosomal disorder is characterized by the karyotype 47,XXY?

Accepted Answer

Klinefelter syndrome

Question 7

A deletion occurs on chromosome 5, resulting in a syndrome characterized by intellectual disability and a cat-like cry in infants. What is this syndrome called?

Accepted Answer

Cri du chat syndrome

Question 8

Which of the following best explains why individuals with Down syndrome have characteristic facial features and developmental delays?

Accepted Answer

They have three copies of chromosome 21, leading to gene dosage imbalance.

Question 9

Which chromosomal abnormality is most commonly associated with chronic myelogenous leukemia (CML)?

Accepted Answer

A reciprocal translocation between chromosomes 9 and 22

Question 10

Polyploidy is more common in plants than in animals. Which of the following best explains why polyploidy can be advantageous in plants?

Accepted Answer

It increases genetic variation and can lead to new species.

Question 11

A patient is diagnosed with Turner syndrome. Which of the following karyotypes would you expect to find in this individual?

Accepted Answer

45,X

Question 12

Which of the following chromosomal changes is LEAST likely to affect the phenotype of an organism?

Accepted Answer

A reciprocal translocation that does not disrupt any gene

Question 13

If a human zygote is monosomic for chromosome 7, how many total chromosomes does it have?

Accepted Answer

45

Question 14

Which of the following best describes a translocation?

Accepted Answer

A segment of one chromosome breaks off and attaches to a nonhomologous chromosome.

Question 15

A woman is found to have a karyotype of 47,XXX. Which of the following statements is most accurate regarding her phenotype?

Accepted Answer

She will be female and may be taller than average, but is often phenotypically normal.

Question 16

Which of the following is a possible consequence of a chromosomal inversion?

Accepted Answer

Altered gene expression due to position effects

Question 17

A plant species is found to have $$4n$$ chromosomes in its somatic cells. What is the term for this condition?

Accepted Answer

Tetraploidy

Question 18

Which of the following scenarios is most likely to result in a viable human offspring?

Accepted Answer

Trisomy 21

Question 19

Which of the following best explains why extra copies of the Y chromosome have relatively mild effects compared to extra copies of the X chromosome?

Accepted Answer

The Y chromosome carries relatively few genes.

Chromosomal Basis of Inheritance and Human Chromosomal Disorders

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