Lecture 2 - DNA & RNA Structure Flashcards
1
Q
A
Adenine
2
Q
A
Guanine
3
Q
A
Cytosine
4
Q
A
Thymine
5
Q
A
Uracil
6
Q
What gives DNA such a long half-life?
A
Phosphodiester linkages
RNA is much less stable because of 2’ -OH
7
Q
What are the stabilizing factors in duplex DNA?
A
- Stacking interactions due to pi-bond overlaps between bases (most important).
- Hydrophobic effect (hydrophobic bases on inside and negatively charged phosphates on outside of helix.
- Hydrogen bonding (provides for specificity and stability).
8
Q
Three types of DNA helices
A
A
B - predominant in nature
Z - left-handed helix
9
Q
Types of repeats
A
Inverted - responsible for cruciform structure in DNA
Mirror
Direct
10
Q
Type of base-pairing responsible for triple helices
A
Hoogsteen
11
Q
Hereditary persistence of fetal hemoglobin (HPFH)
A
Genetic mutation prevents triple helix that acts as a brake for expression of fetal hemoglobin
12
Q
Most prevelant type of cellular RNA
A
rRNA (80%)
mRNA (5%)
tRNA (15%)
13
Q
What are ribosomes primarily made of?
A
rRNA
catalytic center is all RNA
