Nucleic Acids Flashcards
name the 2 types of base substituents
Pyrimidines
Purines
Are pyrimidines monocyclic or bicyclic?
monocyclic
Are purines monocyclic or bicyclic?
bicyclic
Define tautomerism
Any reaction involving the intramolecular transfer of a proton
Give the 2 purines
Adenine
Guanine
Give the 2 pyrimidines
Thymine
Cytosine
Whats the tautomerism for adenine?
Amine –> imine
Whats the tautomerism for Cytosine?
amino –> imino
Whats the tautomerism for Guanine?
keto –> enol
Whats the tautomerism for Thymine?
keto –> enol
What do nucleotides contain, which nucleosides don’t?
Phosphate bound to 3’ or 5’, or the 2’ in RNA
The nucleosides point of attachment to the base is the ____ position of pyrimidines and is the ____ position of purines.
N-1
N-9
What is the functional difference of the 2’ R group between DNA and RNA?
The 2’ group of RNA is OH
The 2’ group of DNA is H
Why is RNA more reactive than DNA?
The lone pair on the OH acts as a nucleophile
Define polymerisation
Linking nucleotides together by phosphodiester bonds
What is the most common helical form of DNA
B form - 10 bp per turn
In DNA, the negatively charged sugar-phosphate backbone is on the outside protecting the ____ on the inside.
bases
The 2 strands are antiparallel to each other due to the ____ bonding between the ____ - _____ base pairs
Hydrogen
Purine - pyrimidine
Watson and crick base pairing says that oppositely/same charged regions attract together by _____ bonding
oppositely
hydrogen
The double helix provides a chemically stable/unstable environment that protects and stores/releases genetic information
stable
stores
DNA can be induced to form the A - form under _____ humidity
low
How does the A- form of DNA differ from the B - form?
A - form has a wider, more compressed structure and the base pairs are tilted lying slightly of the axis.
What is the helical repeat of A-form?
11 bp per turn
Give an example of a prokaryotic genome
E.coli
