How is the mRNA molecule formed?

How is the mRNA molecule formed?

• A. One DNA strand serves as a template for transcription; RNA nucleotides bind by base pairing; the backbone is formed; RNA polymerase catalyzes synthesis.
• B. RNA is formed by translating DNA into protein.
• C. RNA polymerase uses protein templates to build RNA.
• D. RNA is copied from proteins in the cytoplasm.

Answer: (A)

Transcription is how mRNA is formed. RNA polymerase reads a DNA template strand and joins RNA nucleotides in a sequence complementary to that template. Each incoming ribonucleotide pairs with the DNA base (A with U in RNA, T with A, C with G, G with C), and the sugar-phosphate backbone is built by phosphodiester bonds as the chain grows in the 5' to 3' direction. The resulting mRNA is complementary to the template strand and nearly identical to the coding (non-template) strand, except that uracil replaces thymine. This description fits the process: one DNA strand serves as a template for transcription; RNA nucleotides bind by base pairing; the backbone is formed; RNA polymerase catalyzes synthesis. The other statements mix up the steps or templates involved: transcription, not translation, creates RNA; RNA polymerase uses DNA as a template, not proteins; and RNA isn’t copied from proteins.

Transcription is how mRNA is formed. RNA polymerase reads a DNA template strand and joins RNA nucleotides in a sequence complementary to that template. Each incoming ribonucleotide pairs with the DNA base (A with U in RNA, T with A, C with G, G with C), and the sugar-phosphate backbone is built by phosphodiester bonds as the chain grows in the 5' to 3' direction. The resulting mRNA is complementary to the template strand and nearly identical to the coding (non-template) strand, except that uracil replaces thymine. This description fits the process: one DNA strand serves as a template for transcription; RNA nucleotides bind by base pairing; the backbone is formed; RNA polymerase catalyzes synthesis. The other statements mix up the steps or templates involved: transcription, not translation, creates RNA; RNA polymerase uses DNA as a template, not proteins; and RNA isn’t copied from proteins.