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Flashcards in Exam II Deck (8)
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1

What is the UV absorbance of a protein?

280nm: π-π* transition of aromatic AAs (incl. Trp, Tyr)
210nm: peptide bond

2

What is the UV absorbance of a nucleic acid?

~260nm: π-π* transition of bases

3

What method is used to assess purity of nucleic acid samples?

A260/A280 ratio
Ratios significantly lower than ~1.8 (DNA) or ~2.0 (RNA) may indicate protein contamination

4

What method is used to assess purity of nucleic acid samples?

A260/A280 ratio
Ratios significantly lower than ~1.8 (DNA) or ~2.0 (RNA) may indicate protein contamination

5

What can be said about a molecule that differentially absorbs left or right circularly polarised light?

The molecule is optically active or chiral

6

Enantiomers are identical except for what two exceptions?

They way they interact with circularly polarised light and with other chiral molecules

7

What does FRET require?

a) Spectral overlap (between emission spectra of donor and excitation spectra of acceptor)
b) Distance <10nm (generally between 2-10nm)
c) Correct orientation

8

Why is FRET a sensitive method for distance measurements?

It's sensitivity is proportional to the inverse sixth power of the separation between the donor and the acceptor