Honors Biology Semester 2 Final Exam
with Complete Solutions
What is the role of helicase in DNA replication?
✔✔ Helicase unwinds the DNA double helix by breaking hydrogen bonds between base pairs,
allowing replication to begin.
How does complementary base pairing ensure accuracy during DNA replication?
✔✔ Complementary base pairing (A with T, C with G) ensures that each new strand is an exact
copy of the original template.
What is a codon, and how is it related to DNA?
✔✔ A codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino
acid or stop signal during translation.
What is the significance of the 5' and 3' ends in DNA structure?
✔✔ The 5' and 3' ends refer to the orientation of the sugar-phosphate backbone, and DNA
replication occurs in the 5' to 3' direction.
1
, How does RNA polymerase contribute to transcription?
✔✔ RNA polymerase binds to DNA and synthesizes mRNA by adding RNA nucleotides
complementary to the DNA template.
What is the purpose of introns and exons in genes?
✔✔ Exons code for proteins, while introns are non-coding regions that are spliced out during
RNA processing.
How do mutations in DNA affect protein synthesis?
✔✔ Mutations can lead to changes in the mRNA sequence, potentially altering the amino acid
sequence and the resulting protein's function.
What is the role of ribosomal RNA (rRNA) in translation?
✔✔ rRNA is a key component of ribosomes, where it helps assemble amino acids into proteins
based on the mRNA sequence.
Why is DNA described as a "universal genetic code"?
✔✔ DNA is considered universal because the genetic code is the same in almost all organisms,
using the same nucleotide sequences to specify amino acids.
2
with Complete Solutions
What is the role of helicase in DNA replication?
✔✔ Helicase unwinds the DNA double helix by breaking hydrogen bonds between base pairs,
allowing replication to begin.
How does complementary base pairing ensure accuracy during DNA replication?
✔✔ Complementary base pairing (A with T, C with G) ensures that each new strand is an exact
copy of the original template.
What is a codon, and how is it related to DNA?
✔✔ A codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino
acid or stop signal during translation.
What is the significance of the 5' and 3' ends in DNA structure?
✔✔ The 5' and 3' ends refer to the orientation of the sugar-phosphate backbone, and DNA
replication occurs in the 5' to 3' direction.
1
, How does RNA polymerase contribute to transcription?
✔✔ RNA polymerase binds to DNA and synthesizes mRNA by adding RNA nucleotides
complementary to the DNA template.
What is the purpose of introns and exons in genes?
✔✔ Exons code for proteins, while introns are non-coding regions that are spliced out during
RNA processing.
How do mutations in DNA affect protein synthesis?
✔✔ Mutations can lead to changes in the mRNA sequence, potentially altering the amino acid
sequence and the resulting protein's function.
What is the role of ribosomal RNA (rRNA) in translation?
✔✔ rRNA is a key component of ribosomes, where it helps assemble amino acids into proteins
based on the mRNA sequence.
Why is DNA described as a "universal genetic code"?
✔✔ DNA is considered universal because the genetic code is the same in almost all organisms,
using the same nucleotide sequences to specify amino acids.
2
