Question

what is a codon?
a. a type of rna that carries genetic information
b. a protein that assists in dna replication
c. a sequence of three nucleotides on mrna that specifies an amino acid
d. an enzyme that synthesizes rna

what is the function of rna polymerase during transcription?
a. synthesizes dna from an mrna template
b. translates mrna into proteins
c. forms peptide bonds during translation
d. synthesizes mrna from a dna template

what is the key difference between dna and mrna?
a. dna is found in the cytoplasm, while mrna is in the nucleus.
b. mrna is double-stranded, while dna is single-stranded.
c. dna contains uracil, while mrna contains thymine.
d. mrna is single-stranded, while dna is double-stranded.

Explanation:

First Question: What is a codon?

• Option a: The type of RNA carrying genetic info is mRNA, not a codon. Eliminate a.
• Option b: Proteins assisting DNA replication (e.g., helicase) are not codons. Eliminate b.
• Option c: A codon is defined as a three - nucleotide sequence on mRNA that codes for an amino acid. This matches the definition.
• Option d: The enzyme that synthesizes RNA is RNA polymerase, not a codon. Eliminate d.

• Option a: Synthesizing DNA from mRNA is reverse transcription (done by reverse transcriptase), not RNA polymerase's function. Eliminate a.
• Option b: Translating mRNA into proteins is done by ribosomes, not RNA polymerase. Eliminate b.
• Option c: Forming peptide bonds during translation is done by ribosomes, not RNA polymerase. Eliminate c.
• Option d: During transcription, RNA polymerase synthesizes mRNA using a DNA template. This is the correct function.

• Option a: DNA is in the nucleus (and some in mitochondria/chloroplasts), mRNA is made in the nucleus and moves to the cytoplasm. So this is incorrect. Eliminate a.
• Option b: mRNA is single - stranded, DNA is double - stranded. So this is incorrect. Eliminate b.
• Option c: DNA contains thymine, mRNA contains uracil. So this is incorrect. Eliminate c.
• Option d: mRNA is single - stranded, while DNA is double - stranded. This is a key structural difference.

Answer:

c. A sequence of three nucleotides on mRNA that specifies an amino acid

Second Question: What is the function of RNA polymerase during transcription?