Purines, pyrimidines- Properties and synthesis

Question 1

Nucleus

Answer 1

BASIC COMPOUNDS
arginine and lysine rich
\+ charge= polymers of amino acids, proteins (histones)
ACIDIC COMPOUNDS
- charge=polymers of nucleotides 
nucleic acids

Question 2

mRNA

Answer 2

carries info encoded in genes to sites of protein synthesis

Question 3

nucleotides

Answer 3

ROLES:
metabolic
storage
cofactors- NAD+
cell signalling- cyclic AMP

Nitrogenous base + pentose monosaccharide + phosphate

Pyrimidine- add ending idine
Purine- add ending osine

Question 4

Phosphate

Answer 4

Net charge of -2

pKA=2.12

Question 5

Pentose

Answer 5

5 carbon atoms
Ribose exists as a straight chain
Ring is not planar- can occur in a variety of conformations

4/5 atoms are in the same plane

Question 6

Nitrogenous bases

Answer 6

Heterocyclic aromatic amines - fundamental to coding information of nucleic acids

Pyrimidine– 6 membered ring with two N (N1 bonds to pentose) AG
Purine– pyrimidine fused to imidazole ring (N9 bonds to pentose) CUT

Question 7

Purines and pyrimidine

Answer 7

Hydrophobic and insoluble in water

Can undergo ketones/enol tautomerism
Keto (lactam) form predominates at pH7
Decrease pH the enrol (lactim) form predominates

Double bonds–result in bases being highly conjugated

Resonance makes the ring more stable, absorb 260nm UV light
compared to 280nm for proteins

Question 8

Bond between ribose and base

Answer 8

B-Glycosidic linkage

=nucleoside, add phosphate to get nucleotide

Question 9

Nucleoside

Answer 9

Base + sugar
Pyrimidine- add ending idylate
Purine- add ending late