BJU Biochemistry I: DNA/RNA Quiz

Adenine (purine)

What molecule is this?

Guanine (purine)

What molecule is this?

Cytosine (pyrimidine)

What molecule is this?

Thymine (pyrimidine)

What molecule is this?

Uracil (pyrimidine)

What molecule is this?

5-Methylcytosine

What molecule is this?

Thymine is uracil with an extra methyl group

5-methycytosine is a cytosine with an extra methyl group

What molecule is simply a different molecule with a methyl group added on the 5th carbon?

Adenosine (nucleoside)

What molecule is this?

Guanosine (nucleoside)

What molecule is this?

Cytidine (nucleoside)

What molecule is this?

Uridine (nucleoside)

What molecule is this?

Adenosine 5’-monophosphate (AMP) (nucleotide)

What molecule is this?

Guanosine 5’-monophosphate (GMP) (nucleotide)

What molecule is this?

Cytidine 5’-monophosphate (CMP) (nucleotide)

What molecule is this?

Uridine 5’-monophosphate (UMP) (nucleotide)

What molecule is this?

Nucleosides are coupled with a ribose/deoxyribose to a base

Nucleotides have a ribose/deoxyribose, base, and a 5’-monophosphate group

What is the primary difference between nucleosides and nucleotides?

glycosidic bond

What type of bond links a base to the ribose/deoxyribose?

Most effected to least effected:

• Nucleotides (base + sugar + phosphate(s)): the base plus phosphate groups are the most pH sensitive. The phosphate groups are strongly ionizable and as pH increases, the phosphate becomes increasingly deprotonated and negatively charged

• Nucleosides (base + sugar): the base still has the same ionizable groups, so pH can affect it just as it does with bases alone, but while the sugar has -OH groups, they tend to not change protonation significantly.

• Bases (purines/pyrimidines): contain N atoms that can lose/gain H+ depending on pH. At higher pH’s, certain acidic groups can lose H+

Structurally, what would happen to each group if pH was changed (ex: structurally, what will be more affect by a pH change?)