BGM1002/L14 DNA Structure Flashcards
What was the Franklin and Wilkins experiment (1952)?
X-ray fibre diffraction crystallography
How can the structure of a molecule be calculated from the Franklin and Wilkins experiment (1952)?
Using distances and diffraction
What did ‘Plate 51’ suggest in the Franklin and Wilkins experiment (1952)?
Symmetry and double helix structure of DNA
What did the angle between two arms of 60 represent in the Franklin and Wilkins experiment (1952)?
10 repeating units for 34A spacing
Helical radius of 10A
Give 3 features of DNA discovered from the Watson & Crick experiment.
Double-helical
Right-handed
Two anti-parallel strands 5’-3’ & 3’-5’
Backbone on outside of helix
Hydrogen bonds between base pairs
Give 2 features of DNA that contribute to its structural stability.
Hydrophobic effect
Base pair hydrogen bonds
Base pair stacking
Cooperativity
Give 3 features of the major groove.
22A wide
Information-rich
Can be read without unwinding
Exploited by transcription factors
Tx factor c-Myc-Max binds
Give 2 features of the minor groove.
Information-poor
Less frequenty used for sequence recognition
Binding typically alters DNA architecture
Give the 3 models of DNA replication.
Semiconservative
Conservative
Dispersive
Name 4 requirements for DNA replication.
dNTP precursors
DNA polymerases
Primers
Buffer
Which way is DNA synthesised?
5’-3’
How are mismatched nucleotides removed from newly synthesised DNA?
3’-5’ exonucleases
What is DnaB helicase recuited by?
DnaA
What is DnaB helicase loaded around?
ssDNA
What is DnaB helicase translocation dependent on?
ATPase
