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Portage BIOD 210 Genetics - Module 5
Exam | Questions with Correct Verified
Answers | Latest 2026/2027 Update
Guaranteed Pass
Exam Structure:
Subject: Genetics
Source: BIOD 210 Module 5 Exam
Format: Q & A with Rationales
1. DNA pentose sugar is called:
A. 2-deoxyribose
Correct Answer: 2-deoxyribose
Rationale:
1. The sugar in DNA is 2-deoxyribose, which lacks a hydroxyl group at
the 2' carbon compared to ribose.
2. This chemical difference makes DNA more stable and less prone to
hydrolysis than RNA.
3. This is a fundamental distinction between DNA and RNA structure.
2. RNA pentose sugar is called:
A. Ribose
Correct Answer: Ribose
Rationale:
1. The sugar in RNA is ribose, which has a hydroxyl group at both the 2'
and 3' carbons.
2. The presence of the 2'-OH makes RNA more reactive and less
chemically stable than DNA.
3. This structural difference underlies the different biological roles of
DNA (storage) and RNA (transmission, catalysis).
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3. Define nucleoside.
A. Base + sugar (missing phosphate group)
Correct Answer: Base + sugar (missing phosphate group)
Rationale:
1. A nucleoside consists of a nitrogenous base covalently attached to a
pentose sugar (ribose or deoxyribose) but lacks a phosphate group.
2. Examples include adenosine, guanosine, cytidine, thymidine, and
uridine.
3. Nucleosides are the building blocks of nucleotides.
4. Define nucleotide.
A. Base + sugar + phosphate group
Correct Answer: Base + sugar + phosphate group
Rationale:
1. A nucleotide is a nucleoside with one or more phosphate groups
attached to the sugar's 5' carbon.
2. Nucleotides are the monomers that polymerize to form nucleic acids
(DNA and RNA).
3. They also serve as energy carriers (e.g., ATP) and signaling molecules
(e.g., cAMP).
5. G binds to:
A. C with 3 hydrogen bonds
Correct Answer: C with 3 hydrogen bonds
Rationale:
1. Guanine (G) and cytosine (C) form three hydrogen bonds in DNA and
RNA.
2. This triple-bond pairing is stronger than the A-T/U pairing,
contributing to the stability of GC-rich regions of DNA.
3. This principle is key to understanding DNA melting temperature and
replication fidelity.
6. A binds to:
A. T with 2 hydrogen bonds (or U in RNA)
Correct Answer: T with 2 hydrogen bonds (or U in RNA)
Rationale:
Portage BIOD 210 Genetics - Module 5
Exam | Questions with Correct Verified
Answers | Latest 2026/2027 Update
Guaranteed Pass
Exam Structure:
Subject: Genetics
Source: BIOD 210 Module 5 Exam
Format: Q & A with Rationales
1. DNA pentose sugar is called:
A. 2-deoxyribose
Correct Answer: 2-deoxyribose
Rationale:
1. The sugar in DNA is 2-deoxyribose, which lacks a hydroxyl group at
the 2' carbon compared to ribose.
2. This chemical difference makes DNA more stable and less prone to
hydrolysis than RNA.
3. This is a fundamental distinction between DNA and RNA structure.
2. RNA pentose sugar is called:
A. Ribose
Correct Answer: Ribose
Rationale:
1. The sugar in RNA is ribose, which has a hydroxyl group at both the 2'
and 3' carbons.
2. The presence of the 2'-OH makes RNA more reactive and less
chemically stable than DNA.
3. This structural difference underlies the different biological roles of
DNA (storage) and RNA (transmission, catalysis).
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3. Define nucleoside.
A. Base + sugar (missing phosphate group)
Correct Answer: Base + sugar (missing phosphate group)
Rationale:
1. A nucleoside consists of a nitrogenous base covalently attached to a
pentose sugar (ribose or deoxyribose) but lacks a phosphate group.
2. Examples include adenosine, guanosine, cytidine, thymidine, and
uridine.
3. Nucleosides are the building blocks of nucleotides.
4. Define nucleotide.
A. Base + sugar + phosphate group
Correct Answer: Base + sugar + phosphate group
Rationale:
1. A nucleotide is a nucleoside with one or more phosphate groups
attached to the sugar's 5' carbon.
2. Nucleotides are the monomers that polymerize to form nucleic acids
(DNA and RNA).
3. They also serve as energy carriers (e.g., ATP) and signaling molecules
(e.g., cAMP).
5. G binds to:
A. C with 3 hydrogen bonds
Correct Answer: C with 3 hydrogen bonds
Rationale:
1. Guanine (G) and cytosine (C) form three hydrogen bonds in DNA and
RNA.
2. This triple-bond pairing is stronger than the A-T/U pairing,
contributing to the stability of GC-rich regions of DNA.
3. This principle is key to understanding DNA melting temperature and
replication fidelity.
6. A binds to:
A. T with 2 hydrogen bonds (or U in RNA)
Correct Answer: T with 2 hydrogen bonds (or U in RNA)
Rationale:
