Molecular Biology Concepts

What is the primary difference between DNA replication and transcription?

• DNA replication occurs in the cytoplasm; transcription occurs in the nucleus.

• DNA replication involves RNA polymerase; transcription involves DNA polymerase.

• DNA replication copies the entire DNA; transcription synthesizes RNA from a specific DNA segment.

• DNA replication produces proteins; transcription produces lipids.

Which enzyme is responsible for unwinding the DNA double helix during replication?

• nuclease

• ligase

• helicase

• polymerase

What role does RNA polymerase play in transcription?

• RNA polymerase replicates DNA before transcription.

• RNA polymerase breaks down RNA during transcription.

• RNA polymerase synthesizes RNA from a DNA template during transcription.

• RNA polymerase transports amino acids to the ribosome.

Define a point mutation and provide an example.

• A point mutation involves changes in multiple nucleotides simultaneously.

• An example of a point mutation is the deletion of an entire gene.

• Point mutations only occur in RNA, not in DNA.

• A point mutation is a change in a single nucleotide in the DNA sequence, such as the substitution of adenine with thymine in the hemoglobin gene.

What is the significance of codons in protein synthesis?

• Codons are crucial for translating genetic information into proteins by specifying the sequence of amino acids.

• Codons are responsible for DNA replication.

• Codons are involved in the formation of ribosomes.

• Codons determine the structure of RNA molecules.

How do silent mutations affect the protein produced?

• Silent mutations result in a shorter protein.

• Silent mutations do not affect the protein produced.

• Silent mutations cause a loss of protein function.

• Silent mutations lead to a completely different protein.

What is the function of a promoter in gene expression?

• To bind ribosomes during translation

• To enhance the stability of mRNA

• To regulate protein folding

• The function of a promoter in gene expression is to initiate transcription of a gene.

Explain the difference between a missense mutation and a nonsense mutation.

• A missense mutation affects the DNA sequence, while a nonsense mutation does not.

• A missense mutation creates a premature stop codon, while a nonsense mutation changes one amino acid.

• A missense mutation changes one amino acid in a protein, while a nonsense mutation creates a premature stop codon.

• A missense mutation results in a longer protein, while a nonsense mutation shortens the protein.

How does the orientation of a gene affect its transcription?

• The orientation of a gene has no effect on transcription.

• Gene orientation only influences protein folding, not transcription.

• Transcription occurs in both directions regardless of gene orientation.

• The orientation of a gene affects its transcription by determining the direction of RNA synthesis and which DNA strand is used as the template.

What enzyme is involved in the synthesis of new DNA strands during replication?

• Helicase

• RNA polymerase

• DNA polymerase

• Ligase