DNA Chemistry Flashcards
(26 cards)
What 4 nitrogenous bases are used in DNA?
Adenine, guanine, cytosine, and thymine
What 4 nitrogenous bases are used in RNA?
Adenine, guanine, cytosine, and uracil
What is the shape of a purine base?
Double ring
What is the shape of a pyrimidine base?
single ring
What does acid form when hydrolyzing DNA and RNA?
purine bases, pyrimidine nucleosides, sugar moiety, and phosphates
What does base hydrolysis form with DNA and RNA?
DNA is resistant to base hydrolysis.
RNA forms nucleoside monophosphate
What direction are the DNA double helixes?
Right
Where are polar groups in the DNA helix?
Phosphates project outward to interact with proteins. Negatively charged phosphates make complex with Na, Ca, and K to stabilize the helix
Where are non-polar groups in the DNA helix?
The interior of the molecule because they are extremely hydrophobic
What force contributes greatly to helix stability due to the closeness of the nitrogen bases
Van der Waals
What base pairing has a stronger bond: AT or GC?
GC due to the double bonds
What is the distance for (1) one complete turn and (2) between stacked nitrogenous bases?
1) 3.4nm
2) 0.34 nm
How many bases are in each conformation of DNA?
A—11 (tilted bases relative to long axis)
B—10
C—9 (probably doesn’t occur in vivo)
Z—12 (is a left helix)
Hypochromic effect
Tightly stacked bases are less likely to be altered by UV rays
Southern Blotting
DNA sample, used for gene structure/complexity
Northern Blotting
RNA sample, used to measure mRNA levels
Western Blotting
Protein sample
What is necessary to create a DNA library
Vectors
Ligation
Joining of DNA via phosphodiester bonds
What allows DNA to be packaged into a bacteriophage protein coat?
COSmids
Non repetitive DNA sequence frequency
Usually where transcription takes place
Why are histones base proteins?
Have high levels of arginine and lysine
Octamer
The core of 8 histones that DNA wraps around
From which histone are solenoid structures formed?
Histone 1
