,BIOD 210 Module 6 Exam | Q&A | 2026/2027 | Genetics | Portage
Learning
1. A chromosomal aberration is best defined as:
A) A change in the DNA sequence of a single gene
B) An alteration to the chromosome that results in a change to the total
number of chromosomes, deletions or additions to the chromosome, or
complete rearrangement of chromosomal segments
C) A mutation that occurs in the mitochondrial DNA
D) A change in the expression of a gene without changing the DNA sequence
Correct Answer: An alteration to the chromosome that results in a change to
the total number of chromosomes, deletions or additions to the chromosome,
or complete rearrangement of chromosomal segments
Rationale: "Chromosomal aberration" is a broad term that includes numerical
changes (aneuploidy, polyploidy) and structural changes (deletions,
insertions, duplications, translocations). All of these alter chromosome
number or structure compared with the normal karyotype.
2. True or False: Sex chromosomes occur in pairs in all organisms.
A) True
B) False
Correct Answer: False
Rationale: In humans, many individuals do have paired sex chromosomes
(XX or XY), but this is not universally true across species or even across all
viable human karyotypes (e.g., XO, XXX, XXY). Because the statement is
absolute ("occur in pairs"), it is considered false when viewed in a broader
genetic context.
,3. Which of the following is NOT a type of structural chromosomal
aberration?
A) Deletion
B) Duplication
C) Trisomy
D) Translocation
Correct Answer: Trisomy
Rationale: Trisomy is a numerical chromosomal abnormality (aneuploidy), not
a structural aberration. Structural aberrations include deletions, duplications,
insertions, inversions, and translocations.
4. A deletion is best described as:
A) The addition of a chromosomal segment
B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
D) The movement of a chromosomal segment to a non-homologous
chromosome
Correct Answer: The loss of a chromosomal segment
Rationale: A deletion is the loss of a chromosomal segment, which can result
in the loss of important genes. This is one of the main classes of structural
chromosome changes that alter gene dosage and can lead to recognizable
syndromes.
5. A duplication is best described as:
A) The addition of a chromosomal segment
, B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
D) The movement of a chromosomal segment to a non-homologous
chromosome
Correct Answer: The repeat of a chromosomal segment
Rationale: A duplication is the repeat of a chromosomal segment, resulting in
extra copies of genes. This can disrupt gene function due to altered gene
dosage.
6. An insertion is best described as:
A) The addition of a chromosomal segment
B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
D) The movement of a chromosomal segment to a non-homologous
chromosome
Correct Answer: The addition of a chromosomal segment
Rationale: An insertion is the addition of a chromosomal segment, which may
come from another chromosome or from within the same chromosome. This
can disrupt gene function.
7. A translocation is best described as:
A) The addition of a chromosomal segment
B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
Learning
1. A chromosomal aberration is best defined as:
A) A change in the DNA sequence of a single gene
B) An alteration to the chromosome that results in a change to the total
number of chromosomes, deletions or additions to the chromosome, or
complete rearrangement of chromosomal segments
C) A mutation that occurs in the mitochondrial DNA
D) A change in the expression of a gene without changing the DNA sequence
Correct Answer: An alteration to the chromosome that results in a change to
the total number of chromosomes, deletions or additions to the chromosome,
or complete rearrangement of chromosomal segments
Rationale: "Chromosomal aberration" is a broad term that includes numerical
changes (aneuploidy, polyploidy) and structural changes (deletions,
insertions, duplications, translocations). All of these alter chromosome
number or structure compared with the normal karyotype.
2. True or False: Sex chromosomes occur in pairs in all organisms.
A) True
B) False
Correct Answer: False
Rationale: In humans, many individuals do have paired sex chromosomes
(XX or XY), but this is not universally true across species or even across all
viable human karyotypes (e.g., XO, XXX, XXY). Because the statement is
absolute ("occur in pairs"), it is considered false when viewed in a broader
genetic context.
,3. Which of the following is NOT a type of structural chromosomal
aberration?
A) Deletion
B) Duplication
C) Trisomy
D) Translocation
Correct Answer: Trisomy
Rationale: Trisomy is a numerical chromosomal abnormality (aneuploidy), not
a structural aberration. Structural aberrations include deletions, duplications,
insertions, inversions, and translocations.
4. A deletion is best described as:
A) The addition of a chromosomal segment
B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
D) The movement of a chromosomal segment to a non-homologous
chromosome
Correct Answer: The loss of a chromosomal segment
Rationale: A deletion is the loss of a chromosomal segment, which can result
in the loss of important genes. This is one of the main classes of structural
chromosome changes that alter gene dosage and can lead to recognizable
syndromes.
5. A duplication is best described as:
A) The addition of a chromosomal segment
, B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
D) The movement of a chromosomal segment to a non-homologous
chromosome
Correct Answer: The repeat of a chromosomal segment
Rationale: A duplication is the repeat of a chromosomal segment, resulting in
extra copies of genes. This can disrupt gene function due to altered gene
dosage.
6. An insertion is best described as:
A) The addition of a chromosomal segment
B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
D) The movement of a chromosomal segment to a non-homologous
chromosome
Correct Answer: The addition of a chromosomal segment
Rationale: An insertion is the addition of a chromosomal segment, which may
come from another chromosome or from within the same chromosome. This
can disrupt gene function.
7. A translocation is best described as:
A) The addition of a chromosomal segment
B) The loss of a chromosomal segment
C) The repeat of a chromosomal segment
