91Ó°ÊÓ

Draw a structural formula for each nucleotide. (a) \(2^{\prime}\)-Deoxythymidine \(5^{\prime}\)-monophosphate (b) \(2^{\prime}\)-Deoxythymidine \(3^{\prime}\)-monophosphate

Draw a structural formula for the section of DNA that contains the base sequence CTG and is phosphorylated at the \(3^{\prime}\) end only.

$$ \text { Write the complementary DNA base sequence for } 5^{\prime}-\mathrm{CCGTACGA}-3^{\prime} \text {. } $$

Here is a portion of the nucleotide sequence in phenylalanine tRNA. $$ \text { 3'-ACCACCUGCUCAGGCCUU-5' } $$ Write the nucleotide sequence of its DNA complement.

The following section of DNA codes for oxytocin, a polypeptide hormone. $$ \text { 3'ACG-ATA-TAA-GTT-TTA-ACG-GGA-GAA-CCA-ACT-5' } $$ (a) Write the base sequence of the mRNA synthesized from this section of DNA. (b) Given the sequence of bases in part (a), write the primary structure of oxytocin.

Draw a structural formula for a nucleoside composed of the following. (a) \(\alpha\)-D-Ribose and adenine (b) \(\beta\)-2-Deoxy-D-ribose and cytosine

Nucleosides are stable in water and in dilute base. In dilute acid, however, the glycosidic bond of a nucleoside undergoes hydrolysis to give a pentose and a heterocyclic aromatic amine base. Propose a mechanism for this acid- catalyzed hydrolysis.

Explain the difference in structure between a nucleoside and a nucleotide.

Draw a structural formula for each nucleotide, and estimate its net charge at \(\mathrm{pH} 7.4\), the \(\mathrm{pH}\) of blood plasma. (a) \(2^{\prime}\)-Deoxyadenosine \(5^{\prime}\)-triphosphate (dATP) (b) Guanosine \(3^{\prime}\)-monophosphate (GMP) (c) \(2^{\prime}\)-Deoxyguanosine \(5^{\prime}\)-diphosphate (dGDP)

Why are deoxyribonucleic acids called acids? What are the acidic groups in their structure?