BIOD 210 Module 4 Exam – Genetics (Portage Learning) (2026) Actual Questions with Verified Answers | Take & Pass the Exam

BIOD 210 Module 4 Exam – Genetics (Portage Learning) (2026) Actual Questions with Verified Answers |
Take & Pass the Exam


Questions 1–250
Section 1: Mutation Definitions and Classifications (Questions 1–50)


1. What is the broadest definition of a mutation?
A) A change in the amino acid sequence of a protein
B) A heritable change in the nucleotide sequence of DNA
C) A change in the phenotype of an organism
D) An alteration in chromosome number
Answer B: A heritable change in the nucleotide sequence of DNA
Rationale: A mutation is any heritable change in the DNA sequence, ranging from point mutations to
chromosomal rearrangements.




2. A mutation that occurs in a gamete is classified as:
A) Somatic mutation
B) Germline mutation
C) Induced mutation
D) Spontaneous mutation
Answer B: Germline mutation
Rationale: Germline mutations occur in cells that produce gametes and can be passed to offspring.




3. Which of the following is an example of a spontaneous mutation?
A) Mutation caused by UV radiation
B) Mutation caused by a chemical mutagen
C) Mutation due to replication error
D) Mutation induced by X-rays
Answer C: Mutation due to replication error
Rationale: Spontaneous mutations arise naturally from DNA replication errors, depurination, deamination,
or oxidative damage.

,4. A point mutation that changes a single nucleotide but does not change the amino acid is called:
A) Missense mutation
B) Nonsense mutation
C) Silent mutation
D) Frameshift mutation
Answer C: Silent mutation
Rationale: Silent mutations do not alter the amino acid due to the degeneracy of the genetic code.




5. A mutation that changes a codon from UAC (tyrosine) to UAG (stop codon) is an example of:
A) Missense mutation
B) Nonsense mutation
C) Silent mutation
D) Frameshift mutation
Answer B: Nonsense mutation
Rationale: A nonsense mutation creates a premature stop codon, leading to a truncated protein.




6. A mutation that substitutes a purine for a pyrimidine (e.g., A to C) is called a:
A) Transition
B) Transversion
C) Inversion
D) Deletion
Answer B: Transversion
Rationale: A transversion changes a purine to a pyrimidine or vice versa.




7. Which type of mutation results from the insertion or deletion of nucleotides in a coding region,
altering the reading frame?
A) Point mutation
B) Frameshift mutation
C) Nonsense mutation
D) Missense mutation
Answer B: Frameshift mutation

,Rationale: Insertions or deletions not in multiples of 3 shift the reading frame, altering all downstream
amino acids.




8. The β-globin mutation responsible for sickle cell anemia is a:
A) Silent mutation
B) Missense mutation
C) Nonsense mutation
D) Frameshift mutation
Answer B: Missense mutation
Rationale: Sickle cell anemia results from a missense mutation changing glutamic acid to valine.




9. A transition mutation involves the substitution of:
A) A purine for a pyrimidine
B) A purine for another purine or a pyrimidine for another pyrimidine
C) A nucleotide for an amino acid
D) A base for a sugar
Answer B: A purine for another purine or a pyrimidine for another pyrimidine
Rationale: Transitions are A↔G (purine to purine) or C↔T (pyrimidine to pyrimidine).




10. Which of the following mutagens causes thymine dimers?
A) X-rays
B) UV radiation
C) Base analogs
D) Intercalating agents
Answer B: UV radiation
Rationale: UV radiation causes the formation of covalent bonds between adjacent thymines, creating
thymine dimers.




11. An auxotroph is a bacterium that:
A) Can grow on minimal medium
B) Requires additional nutrients for growth
C) Cannot grow on any medium

, D) Grows only in the presence of antibiotics
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Answer B: Requires additional nutrients for growth
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Rationale: Auxotrophs have mutations in biosynthetic pathways and require supplemented media.
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12. A prototroph is a bacterium that:
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A) Can grow on minimal medium
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B) Requires additional nutrients for growth
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C) Cannot grow on minimal medium
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D) Is resistant to antibiotics
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Answer A: Can grow on minimal medium
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Rationale: Prototrophs can synthesize all essential compounds from minimal nutrients.
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13. A bacterium that can grow well on minimal medium is an example of a:
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A) Auxotroph
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B) Prototroph
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C) Mutant
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D) Transductant
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Answer B: Prototroph j0 j0




Rationale: Prototrophs do not require any additional supplements beyond minimal medium.
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14. Which type of mutation results from exposure to a chemical that alters base pairing?
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A) Spontaneous mutation
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B) Induced mutation
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C) Germline mutation
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D) Silent mutation
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Answer B: Induced mutation j0 j0 j0




Rationale: Induced mutations are caused by external agents (mutagens).
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15. Base analogs such as 5-bromouracil cause mutations by:
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A) Incorporating into DNA and mispairing
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B) Removing amino groups from bases
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C) Inserting between DNA bases
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