BIOD 210 Module 5 Exam (2026) | Portage Learning Genetics – Complete PDF Q&A with Verified Answers & Rationales

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,BIOD 210 Module 5 Exam | (2026) Genetics Exam


Questions | Portage (PDF)



1. The central dogma of molecular biology states that

genetic information flows from:

a) Protein → RNA → DNA

b) DNA → Protein → RNA

c) DNA → RNA → Protein

d) RNA → DNA → Protein

Answer: c

Rationale: The central dogma is DNA transcribed to RNA,

then RNA translated to protein. Reverse transcription

(RNA to DNA) is an exception in retroviruses, not the

standard flow.

2. Which enzyme synthesizes RNA from a DNA template

during transcription?

a) DNA polymerase

b) RNA primase



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,c) RNA polymerase

d) Ligase

Answer: c

Rationale: RNA polymerase catalyzes the formation of

phosphodiester bonds between ribonucleotides, using one

DNA strand as a template.

3. In prokaryotes, the RNA polymerase holoenzyme

consists of the core enzyme plus which subunit necessary

for initiation?

a) α

b) β

c) β '

d) σ (sigma)

Answer: d

Rationale: The sigma factor recognizes the promoter

consensus sequences (-10 and -35 boxes) and directs

RNA polymerase to the correct transcription start site.




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, 4. Which DNA strand is used as a template for

transcription?

a) The coding strand

b) The sense strand

c) The antisense strand

d) Both strands equally

Answer: c

Rationale: The antisense (template) strand is

complementary to the RNA transcript. The coding (sense)

strand has the same sequence as the RNA (except T→U).

5. A mutation that changes a promoter’s -10 box from

TATAAT to TATAAC would most likely:

a) Increase translation efficiency

b) Decrease transcription initiation

c) Have no effect

d) Alter RNA splicing

Answer: b

Rationale: The -10 box (Pribnow box) is critical for RNA

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