BIO 235 - Final Exam Study Guide
2024/2025 Exam Questions and
Corresponding Answers with Surety of
100% Pass Mark
The Central Dogma of molecular biology states that, in cells, biological
information _______.
A. Can be transmitted either from DNA to RNA or from RNA to DNA
B. Moves from DNA to RNA to protein
C. Moves from protein to RNA to DNA
D. Moves from DNA to RNA only if encoded by certain viruses
E. Moves from protein to RNA only if encoded by certain viruses -
🧠ANSWER ✔✔B
What is the exception to the Central Dogma rule? - 🧠ANSWER
✔✔RETROVIRUSES (process goes from RNA to DNA using reverse
transcriptase enzymes)
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,What do retroviruses have that allows them to go from RNA to DNA? -
🧠ANSWER ✔✔Reverse transcriptase enzymes
What category of transposable elements use an RNA copy of their genome
in the process of transposition?
A. Cut-and-paste transposons
B. Composite bacterial transposons
C. Bacterial insertion sequences
D. Retrotransposons
E. Multiple drug resistance plasmids - 🧠ANSWER ✔✔D
Copy-and-paste transposons a.k.a. replicative transposition - 🧠ANSWER
✔✔A new copy of the transposable element is introduced at a new site
while the old copy remains behind at the original site (so the number of
copies of the transposable element increases)
Transposons a.k.a. transposable elements - 🧠ANSWER ✔✔Sequences
that can move about in the genome and are often a cause of mutations
Are direct repeats part of a transposon? - 🧠ANSWER ✔✔NO
Are inverted repeats part of a transposon? - 🧠ANSWER ✔✔YES
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STATEMENT. ALL RIGHTS RESERVED
,Transposition - 🧠ANSWER ✔✔The movement of a transposon
Cut-and-paste transposons a.k.a. nonreplicative transposition - 🧠ANSWER
✔✔Transposable element excises from the old site and inserts at a new
site WITHOUT any increase in the number of its copies
Retrotransposons - 🧠ANSWER ✔✔Elements that transpose through an
RNA intermediate
Mutagenic compounds that fit and "get stuck" between nucleotides of DNA
molecules are called ________, whereas mutagenic compounds that cause
the covalent attachment of a methyl or an ethyl group to bases of DNA are
called ______.
A. De-aminating agents; reactive oxygen molecules
B. Oxidizing agents; glycosylases
C. Intercalating agents; alkylating agents
D. Hydrolases; base analogs
E. Catalytic converters; organic solvents - 🧠ANSWER ✔✔C
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STATEMENT. ALL RIGHTS RESERVED
, Base analogs - 🧠ANSWER ✔✔Chemicals with structures similar to that of
any of the four standard bases of DNA (DNA polymerase canNOT
distinguish these analogs from the standard bases)
Alkylating agents - 🧠ANSWER ✔✔Chemicals that donate alkyl groups like
methyl and ethyl groups
Deamination - 🧠ANSWER ✔✔Removing an amino group
Intercalating agents - 🧠ANSWER ✔✔Produce mutations by sandwiching
themselves (intercalating) between adjacent bases in DNA, distorting the
three-dimensional structure of the helix and causing single-nucleotide
insertions and deletions in replication
What form of radiation causes double-strand breaks in DNA? - 🧠ANSWER
✔✔X-rays (ionizing radiation)
What form of radiation forms pyrimidine dimers (or thymine dimers)? -
🧠ANSWER ✔✔UV rays
Pyrimidine dimers - 🧠ANSWER ✔✔Formation of a chemical bond between
adjacent pyrimidine molecules on the same strand of DNA
Depurination - 🧠ANSWER ✔✔The loss of a purine base from a nucleotide
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
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STATEMENT. ALL RIGHTS RESERVED
2024/2025 Exam Questions and
Corresponding Answers with Surety of
100% Pass Mark
The Central Dogma of molecular biology states that, in cells, biological
information _______.
A. Can be transmitted either from DNA to RNA or from RNA to DNA
B. Moves from DNA to RNA to protein
C. Moves from protein to RNA to DNA
D. Moves from DNA to RNA only if encoded by certain viruses
E. Moves from protein to RNA only if encoded by certain viruses -
🧠ANSWER ✔✔B
What is the exception to the Central Dogma rule? - 🧠ANSWER
✔✔RETROVIRUSES (process goes from RNA to DNA using reverse
transcriptase enzymes)
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
1
STATEMENT. ALL RIGHTS RESERVED
,What do retroviruses have that allows them to go from RNA to DNA? -
🧠ANSWER ✔✔Reverse transcriptase enzymes
What category of transposable elements use an RNA copy of their genome
in the process of transposition?
A. Cut-and-paste transposons
B. Composite bacterial transposons
C. Bacterial insertion sequences
D. Retrotransposons
E. Multiple drug resistance plasmids - 🧠ANSWER ✔✔D
Copy-and-paste transposons a.k.a. replicative transposition - 🧠ANSWER
✔✔A new copy of the transposable element is introduced at a new site
while the old copy remains behind at the original site (so the number of
copies of the transposable element increases)
Transposons a.k.a. transposable elements - 🧠ANSWER ✔✔Sequences
that can move about in the genome and are often a cause of mutations
Are direct repeats part of a transposon? - 🧠ANSWER ✔✔NO
Are inverted repeats part of a transposon? - 🧠ANSWER ✔✔YES
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
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STATEMENT. ALL RIGHTS RESERVED
,Transposition - 🧠ANSWER ✔✔The movement of a transposon
Cut-and-paste transposons a.k.a. nonreplicative transposition - 🧠ANSWER
✔✔Transposable element excises from the old site and inserts at a new
site WITHOUT any increase in the number of its copies
Retrotransposons - 🧠ANSWER ✔✔Elements that transpose through an
RNA intermediate
Mutagenic compounds that fit and "get stuck" between nucleotides of DNA
molecules are called ________, whereas mutagenic compounds that cause
the covalent attachment of a methyl or an ethyl group to bases of DNA are
called ______.
A. De-aminating agents; reactive oxygen molecules
B. Oxidizing agents; glycosylases
C. Intercalating agents; alkylating agents
D. Hydrolases; base analogs
E. Catalytic converters; organic solvents - 🧠ANSWER ✔✔C
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
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STATEMENT. ALL RIGHTS RESERVED
, Base analogs - 🧠ANSWER ✔✔Chemicals with structures similar to that of
any of the four standard bases of DNA (DNA polymerase canNOT
distinguish these analogs from the standard bases)
Alkylating agents - 🧠ANSWER ✔✔Chemicals that donate alkyl groups like
methyl and ethyl groups
Deamination - 🧠ANSWER ✔✔Removing an amino group
Intercalating agents - 🧠ANSWER ✔✔Produce mutations by sandwiching
themselves (intercalating) between adjacent bases in DNA, distorting the
three-dimensional structure of the helix and causing single-nucleotide
insertions and deletions in replication
What form of radiation causes double-strand breaks in DNA? - 🧠ANSWER
✔✔X-rays (ionizing radiation)
What form of radiation forms pyrimidine dimers (or thymine dimers)? -
🧠ANSWER ✔✔UV rays
Pyrimidine dimers - 🧠ANSWER ✔✔Formation of a chemical bond between
adjacent pyrimidine molecules on the same strand of DNA
Depurination - 🧠ANSWER ✔✔The loss of a purine base from a nucleotide
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
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STATEMENT. ALL RIGHTS RESERVED
