BIOD 210 Module 6 Exam – Genetics (Portage Learning) (2026/2027) Actual Questions with Verified Answers | Take & Pass the Exam

BIOD 210 Module 6 Exam – Genetics (Portage Learning) (2026/2027)
Actual Questions with Verified Answers | Take & Pass the Exam

Questions 1–200+


1. Which of the following best defines a chromosomal aberration?
A) A change in a single nucleotide within a 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 change in the DNA sequence that does not affect chromosome structure
D) A mutation that only affects mitochondrial DNA
Answer 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
Rationale: Chromosomal aberration is a broad term that includes numerical changes (aneuploidy,
polyploidy) and structural changes (deletions, insertions, duplications, translocations).




2. True or False: Sex chromosomes occur in pairs in all organisms.
A) True
B) False
Answer B: False
Rationale: While many humans have paired sex chromosomes (XX or XY), this is not universally true across
species or all viable human karyotypes (e.g., XO, XXX, XXY).




3. True or False: Trisomy and monosomy in autosomal chromosomes are generally tolerated better
in animals than in plants.
A) True
B) False
Answer B: False

,Rationale: Plants generally tolerate changes in chromosome number (aneuploidy and polyploidy) better
than animals. Autosomal trisomies or monosomies in animals are often lethal.




4. The region of chromosome 21 responsible for the phenotype of Down syndrome is the:
A) DSCR (Down Syndrome Critical Region)
B) DSTT
C) T21DS
D) DSRR
Answer A: DSCR (Down Syndrome Critical Region)
Rationale: The Down Syndrome Critical Region on chromosome 21 contains genes thought to be responsible
for the characteristic phenotype of trisomy 21.




5. Which of the following is an example of aneuploidy?
A) Triploidy (3n)
B) Trisomy 21 (Down syndrome)
C) Tetraploidy (4n)
D) Polyploidy in plants
Answer B: Trisomy 21 (Down syndrome)
Rationale: Aneuploidy refers to an abnormal number of chromosomes, such as trisomy (three copies of a
chromosome). Polyploidy involves whole sets of chromosomes.




6. Which of the following chromosomal abnormalities results in a female with a single X chromosome
(XO)?
A) Klinefelter syndrome
B) Turner syndrome
C) Triple X syndrome
D) Down syndrome
Answer B: Turner syndrome
Rationale: Turner syndrome (45,X) is caused by monosomy of the X chromosome, resulting in a female
phenotype with ovarian dysgenesis.

,7. Which of the following chromosomal abnormalities results in a male with an extra X chromosome
(XXY)?
A) Turner syndrome
B) Klinefelter syndrome
C) Triple X syndrome
D) Jacobsen syndrome
Answer B: Klinefelter syndrome
Rationale: Klinefelter syndrome (47,XXY) results from nondisjunction, leading to male hypogonadism and
infertility.




8. Cri-du-chat syndrome is caused by a:
A) Trisomy of chromosome 21
B) Deletion on the short arm of chromosome 5
C) Duplication of chromosome 15
D) Translocation between chromosomes 9 and 22
Answer B: Deletion on the short arm of chromosome 5
Rationale: Cri-du-chat syndrome results from a terminal deletion of chromosome 5p, characterized by a cat-
like cry in infancy.




9. What is an intercalary deletion?
A) A deletion that occurs at the end of a chromosome
B) A deletion that occurs within a chromosome (not at the end)
C) A deletion that removes the centromere
D) A duplication of a chromosome segment
Answer B: A deletion that occurs within a chromosome (not at the end)
Rationale: An intercalary deletion occurs within a chromosome, whereas a terminal deletion occurs at the
end.




10. What is a terminal deletion?
A) A deletion that occurs at the end of a chromosome
B) A deletion that occurs within a chromosome
C) A deletion that removes the centromere
D) A duplication of a chromosome segment

, Answer A: A deletion that occurs at the end of a chromosome
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




Rationale: A terminal deletion occurs at the end of a chromosome, while an intercalary deletion occurs
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




j0 within.




11. Which of the following describes a Robertsonian translocation?
j0 j0 j0 j0 j0 j0 j0 j0




A) Exchange of segments between non-homologous chromosomes
j0 j0 j0 j0 j0 j0




B) Fusion of two acrocentric chromosomes at their centromeres
j0 j0 j0 j0 j0 j0 j0 j0




C) Inversion of a chromosome segment
j0 j0 j0 j0 j0




D) Duplication of a chromosome segment
j0 j0 j0 j0 j0




Answer B: Fusion of two acrocentric chromosomes at their centromeres
j0 j0 j0 j0 j0 j0 j0 j0 j0




Rationale: Robertsonian translocations involve the fusion of two acrocentric chromosomes, often resulting
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




j0 in a balanced carrier state.
j0 j0 j0 j0




12. The Philadelphia chromosome is an example of a:
j0 j0 j0 j0 j0 j0 j0 j0




A) Deletion
j0




B) Duplication
j0




C) Translocation
j0




D) Inversion
j0




Answer C: Translocation j0 j0




Rationale: The Philadelphia chromosome results from a reciprocal translocation between chromosomes 9
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




j0 and 22, creating the BCR-ABL fusion gene.
j0 j0 j0 j0 j0 j0




13. Which of the following is a characteristic of mitochondrial DNA (mtDNA)?
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




A) It is inherited from both parents
j0 j0 j0 j0 j0 j0




B) It is inherited maternally
j0 j0 j0 j0




C) It is linear and located in the nucleus
j0 j0 j0 j0 j0 j0 j0 j0




D) It contains genes for all cellular proteins
j0 j0 j0 j0 j0 j0 j0




Answer B: It is inherited maternally
j0 j0 j0 j0 j0




Rationale: Mitochondrial DNA is inherited exclusively from the mother because sperm mitochondria are
j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0 j0




j0 destroyed after fertilization. j0 j0




14. Mitochondrial disorders are typically inherited in which pattern?
j0 j0 j0 j0 j0 j0 j0 j0