BIOL 101 Week 7 Quiz V1 | BIOL 101 Principles of
Biology | Actual Q&A with Rationale (BIOL101
Week 7 Quiz) | Liberty University
1. In the structure of a DNA molecule, the ‘rungs’ of the twisted ladder are composed of
which components?
A. Sugar and phosphate groups
B. Nitrogenous base pairs
C. Amino acid chains
D. Lipid bilayers
Correct Answer: B
Explanation: The DNA double helix is often compared to a twisted ladder where the side
rails are the sugar-phosphate backbones. The internal steps or rungs consist of nitrogenous
bases held together by hydrogen bonds. This molecular architecture allows the genetic
code to be stored securely within the interior of the molecule.
2. Which enzyme is responsible for unwinding the DNA double helix during the process of
replication?
A. Helicase
B. RNA primase
C. DNA ligase
,D. DNA polymerase
Correct Answer: A
Explanation: Helicase functions by breaking the hydrogen bonds between the
complementary nitrogenous bases. This action creates the replication fork, allowing other
enzymes to access the single strands. The mechanical separation of strands is a vital
prerequisite for the synthesis of a new DNA strand.
3. According to the Central Dogma of Molecular Biology, what is the correct flow of genetic
information?
A. RNA to DNA to Protein
B. Protein to RNA to DNA
C. DNA to RNA to Protein
D. DNA to Protein to RNA
Correct Answer: C
Explanation: The flow of genetic information typically begins with the transcription of
DNA into messenger RNA. Subsequently, this RNA transcript is translated by ribosomes
into a functional polypeptide or protein. This sequence is universal across nearly all known
life forms and defines the primary pathway of gene expression.
4. What is the primary function of transfer RNA (tRNA) during the process of translation?
A. It carries the genetic code from the nucleus to the cytoplasm.
, B. It serves as the structural component of the ribosome.
C. It catalyzes the formation of the phosphodiester backbone.
D. It brings the correct amino acid to the ribosome based on the mRNA codon.
Correct Answer: D
Explanation: tRNA molecules act as adaptors that bridge the gap between nucleic acids
and proteins. Each tRNA carries a specific amino acid and possesses an anticodon that
matches the mRNA sequence. This precise interaction ensures that the amino acid
sequence matches the genetic instructions encoded in the mRNA.
5. A sequence of three nucleotides on an mRNA molecule that codes for a specific amino acid
is known as a:
A. Anticodon
B. Codon
C. Promoter
D. Exon
Correct Answer: B
Explanation: The genetic code is read in discrete units called codons, each consisting of
three nitrogenous bases. There are 64 possible codons, most of which specify one of the 20
standard amino acids. The discovery of the triplet nature of the code was a landmark
achievement in understanding biological information processing.
Biology | Actual Q&A with Rationale (BIOL101
Week 7 Quiz) | Liberty University
1. In the structure of a DNA molecule, the ‘rungs’ of the twisted ladder are composed of
which components?
A. Sugar and phosphate groups
B. Nitrogenous base pairs
C. Amino acid chains
D. Lipid bilayers
Correct Answer: B
Explanation: The DNA double helix is often compared to a twisted ladder where the side
rails are the sugar-phosphate backbones. The internal steps or rungs consist of nitrogenous
bases held together by hydrogen bonds. This molecular architecture allows the genetic
code to be stored securely within the interior of the molecule.
2. Which enzyme is responsible for unwinding the DNA double helix during the process of
replication?
A. Helicase
B. RNA primase
C. DNA ligase
,D. DNA polymerase
Correct Answer: A
Explanation: Helicase functions by breaking the hydrogen bonds between the
complementary nitrogenous bases. This action creates the replication fork, allowing other
enzymes to access the single strands. The mechanical separation of strands is a vital
prerequisite for the synthesis of a new DNA strand.
3. According to the Central Dogma of Molecular Biology, what is the correct flow of genetic
information?
A. RNA to DNA to Protein
B. Protein to RNA to DNA
C. DNA to RNA to Protein
D. DNA to Protein to RNA
Correct Answer: C
Explanation: The flow of genetic information typically begins with the transcription of
DNA into messenger RNA. Subsequently, this RNA transcript is translated by ribosomes
into a functional polypeptide or protein. This sequence is universal across nearly all known
life forms and defines the primary pathway of gene expression.
4. What is the primary function of transfer RNA (tRNA) during the process of translation?
A. It carries the genetic code from the nucleus to the cytoplasm.
, B. It serves as the structural component of the ribosome.
C. It catalyzes the formation of the phosphodiester backbone.
D. It brings the correct amino acid to the ribosome based on the mRNA codon.
Correct Answer: D
Explanation: tRNA molecules act as adaptors that bridge the gap between nucleic acids
and proteins. Each tRNA carries a specific amino acid and possesses an anticodon that
matches the mRNA sequence. This precise interaction ensures that the amino acid
sequence matches the genetic instructions encoded in the mRNA.
5. A sequence of three nucleotides on an mRNA molecule that codes for a specific amino acid
is known as a:
A. Anticodon
B. Codon
C. Promoter
D. Exon
Correct Answer: B
Explanation: The genetic code is read in discrete units called codons, each consisting of
three nitrogenous bases. There are 64 possible codons, most of which specify one of the 20
standard amino acids. The discovery of the triplet nature of the code was a landmark
achievement in understanding biological information processing.
