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BIOL180 – UNIT TEST 5: DNA, RNA, AND PROTEIN
SYNTHESIS – PRACTICE EXAM 2026/2027 COMPLETE
CURRENT TESTING QUESTIONS AND CORRECT
ANSWERS WITH DETAILED RATIONALES.
BIOL
Prepare for the BIOL180 Unit Test 5 – DNA, RNA, and Protein Synthesis Exam with this
focused practice resource designed to reinforce essential molecular biology
concepts. Use it to review DNA structure, RNA functions, genetic information,
transcription, translation, and the process of protein synthesis. This resource can help
strengthen your understanding, identify areas that may require additional study, and
improve your test readiness. It provides a structured supplement to your coursework
and supports a more confident approach to the BIOL180 assessment.
MULTIPLE CHOICE.
Section 1: DNA Structure & Function (Q1–Q25)
1. Which statement best describes the primary function of DNA in living
organisms?
A. DNA directly produces energy for cellular activities
B. DNA stores hereditary information that directs cellular functions and
inheritance
C. DNA transports amino acids during protein synthesis
D. DNA breaks down glucose during cellular respiration
Answer: B
Rationale: DNA contains genetic instructions encoded in nucleotide
sequences that determine inherited traits and provide information for
making proteins necessary for cellular activities .
2. Which nitrogenous base is found in RNA but not in DNA?
A. Adenine
B. Cytosine
C. Guanine
D. Uracil
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Answer: D
Rationale: RNA contains uracil (U) instead of thymine (T). During
transcription, uracil pairs with adenine to form RNA molecules .
3. Which of the following correctly lists the complementary DNA base
pairs?
A. A–C and G–T
B. A–T and C–G
C. A–U and C–G
D. A–G and T–C
Answer: B
Rationale: In DNA, adenine always pairs with thymine, while cytosine
pairs with guanine through hydrogen bonds, maintaining the double-helix
structure .
4. Which scientist's experiments provided evidence that DNA is the
transforming principle responsible for heredity?
A. Gregor Mendel
B. Frederick Griffith
C. Thomas Hunt Morgan
D. Charles Darwin
Answer: B
Rationale: Frederick Griffith discovered bacterial transformation, showing
that a hereditary factor could transfer between bacterial cells, although
he did not identify DNA as that factor .
5. Which experiment conclusively demonstrated that DNA, rather than
protein, is the genetic material?
A. Hershey-Chase bacteriophage experiment
B. Meselson-Stahl experiment
C. Franklin's X-ray diffraction experiment
D. Avery's enzyme experiment
Answer: A
Rationale: Hershey and Chase used radioactive labeling to show that DNA
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entered bacterial cells during viral infection while protein did not, proving
DNA carries genetic information .
6. What structural feature makes DNA capable of storing large amounts of
genetic information?
A. The number of phosphate groups
B. The sequence of nitrogenous bases
C. The arrangement of ribose sugars
D. The number of hydrogen bonds between nucleotides
Answer: B
Rationale: The sequence of nitrogenous bases along the DNA strand
encodes genetic information, much like letters forming words and
sentences .
7. Which of the following correctly compares DNA and RNA?
A. DNA contains ribose sugar.
B. RNA is always double-stranded.
C. DNA contains deoxyribose, while RNA contains ribose.
D. Both contain thymine instead of uracil.
Answer: C
Rationale: DNA contains deoxyribose sugar and thymine, whereas RNA
contains ribose sugar and uracil .
8. A sequence of DNA that codes for a functional product is called a:
A. Codon
B. Gene
C. Chromosome
D. Centromere
Answer: B
Rationale: A gene is a segment of DNA containing instructions for
producing a functional product, typically a protein .
9. The structure of DNA is best described as a:
A. Single strand of nucleotides
B. Double helix formed by two complementary strands
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C. Triple helix
D. Circular loop
Answer: B
Rationale: DNA is a double helix formed by two strands of nucleotides
held together by hydrogen bonds between complementary base pairs.
10. Which of the following is NOT a component of a DNA nucleotide?
A. Deoxyribose sugar
B. Phosphate group
C. Nitrogenous base
D. Ribose sugar
Answer: D
Rationale: DNA nucleotides contain deoxyribose sugar, a phosphate
group, and a nitrogenous base. Ribose sugar is found in RNA, not DNA.
11. In DNA, the two strands run in opposite directions. This is referred to
as:
A. Parallel orientation
B. Antiparallel orientation
C. Semiparallel orientation
D. Perpendicular orientation
Answer: B
Rationale: The two strands of DNA run antiparallel to each other, meaning
one strand runs 5' to 3' and the other runs 3' to 5' .
12. Which bond holds the two strands of DNA together?
A. Peptide bond
B. Hydrogen bond
C. Phosphodiester bond
D. Glycosidic bond
Answer: B
Rationale: Hydrogen bonds between complementary base pairs hold the
two DNA strands together. Phosphodiester bonds link nucleotides within
a single strand.
BIOL180 – UNIT TEST 5: DNA, RNA, AND PROTEIN
SYNTHESIS – PRACTICE EXAM 2026/2027 COMPLETE
CURRENT TESTING QUESTIONS AND CORRECT
ANSWERS WITH DETAILED RATIONALES.
BIOL
Prepare for the BIOL180 Unit Test 5 – DNA, RNA, and Protein Synthesis Exam with this
focused practice resource designed to reinforce essential molecular biology
concepts. Use it to review DNA structure, RNA functions, genetic information,
transcription, translation, and the process of protein synthesis. This resource can help
strengthen your understanding, identify areas that may require additional study, and
improve your test readiness. It provides a structured supplement to your coursework
and supports a more confident approach to the BIOL180 assessment.
MULTIPLE CHOICE.
Section 1: DNA Structure & Function (Q1–Q25)
1. Which statement best describes the primary function of DNA in living
organisms?
A. DNA directly produces energy for cellular activities
B. DNA stores hereditary information that directs cellular functions and
inheritance
C. DNA transports amino acids during protein synthesis
D. DNA breaks down glucose during cellular respiration
Answer: B
Rationale: DNA contains genetic instructions encoded in nucleotide
sequences that determine inherited traits and provide information for
making proteins necessary for cellular activities .
2. Which nitrogenous base is found in RNA but not in DNA?
A. Adenine
B. Cytosine
C. Guanine
D. Uracil
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Answer: D
Rationale: RNA contains uracil (U) instead of thymine (T). During
transcription, uracil pairs with adenine to form RNA molecules .
3. Which of the following correctly lists the complementary DNA base
pairs?
A. A–C and G–T
B. A–T and C–G
C. A–U and C–G
D. A–G and T–C
Answer: B
Rationale: In DNA, adenine always pairs with thymine, while cytosine
pairs with guanine through hydrogen bonds, maintaining the double-helix
structure .
4. Which scientist's experiments provided evidence that DNA is the
transforming principle responsible for heredity?
A. Gregor Mendel
B. Frederick Griffith
C. Thomas Hunt Morgan
D. Charles Darwin
Answer: B
Rationale: Frederick Griffith discovered bacterial transformation, showing
that a hereditary factor could transfer between bacterial cells, although
he did not identify DNA as that factor .
5. Which experiment conclusively demonstrated that DNA, rather than
protein, is the genetic material?
A. Hershey-Chase bacteriophage experiment
B. Meselson-Stahl experiment
C. Franklin's X-ray diffraction experiment
D. Avery's enzyme experiment
Answer: A
Rationale: Hershey and Chase used radioactive labeling to show that DNA
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entered bacterial cells during viral infection while protein did not, proving
DNA carries genetic information .
6. What structural feature makes DNA capable of storing large amounts of
genetic information?
A. The number of phosphate groups
B. The sequence of nitrogenous bases
C. The arrangement of ribose sugars
D. The number of hydrogen bonds between nucleotides
Answer: B
Rationale: The sequence of nitrogenous bases along the DNA strand
encodes genetic information, much like letters forming words and
sentences .
7. Which of the following correctly compares DNA and RNA?
A. DNA contains ribose sugar.
B. RNA is always double-stranded.
C. DNA contains deoxyribose, while RNA contains ribose.
D. Both contain thymine instead of uracil.
Answer: C
Rationale: DNA contains deoxyribose sugar and thymine, whereas RNA
contains ribose sugar and uracil .
8. A sequence of DNA that codes for a functional product is called a:
A. Codon
B. Gene
C. Chromosome
D. Centromere
Answer: B
Rationale: A gene is a segment of DNA containing instructions for
producing a functional product, typically a protein .
9. The structure of DNA is best described as a:
A. Single strand of nucleotides
B. Double helix formed by two complementary strands
, Page 4 of 34
C. Triple helix
D. Circular loop
Answer: B
Rationale: DNA is a double helix formed by two strands of nucleotides
held together by hydrogen bonds between complementary base pairs.
10. Which of the following is NOT a component of a DNA nucleotide?
A. Deoxyribose sugar
B. Phosphate group
C. Nitrogenous base
D. Ribose sugar
Answer: D
Rationale: DNA nucleotides contain deoxyribose sugar, a phosphate
group, and a nitrogenous base. Ribose sugar is found in RNA, not DNA.
11. In DNA, the two strands run in opposite directions. This is referred to
as:
A. Parallel orientation
B. Antiparallel orientation
C. Semiparallel orientation
D. Perpendicular orientation
Answer: B
Rationale: The two strands of DNA run antiparallel to each other, meaning
one strand runs 5' to 3' and the other runs 3' to 5' .
12. Which bond holds the two strands of DNA together?
A. Peptide bond
B. Hydrogen bond
C. Phosphodiester bond
D. Glycosidic bond
Answer: B
Rationale: Hydrogen bonds between complementary base pairs hold the
two DNA strands together. Phosphodiester bonds link nucleotides within
a single strand.
