Practical 1 - Spectrophotometry and Electrophoresis Flashcards Preview

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Flashcards in Practical 1 - Spectrophotometry and Electrophoresis Deck (10):
1

Define electrophoresis

Method of analysing molecules based on charge, by measuring their migration in an electric field.

2

Define spectrophotometry

Method of analysing molecules based on their spectral properties

3

What is absorbance?

Fraction of incident light absorbed by a solution which is measured.

Absorbance = log10 (light transmitted through blank solution/light transmitted through test solution)

4

At which wavelength is there maximum haemoglobin absorption?

540nm. Light is green at this wavelength

5

What does addition of sodium dithionite do to haemoglobin?

Removes oxygen

6

What does oxygen binding grant Hb?

Altered e- resonance, so different absorption spectrum to other proteins

7

Methaemoglobin?

Hb with Fe3+ instead of fe2+, caused by oxidation.

This is what gives dried blood its brown colour.

8

What is the Beer-Lambert Law?

A = E x c x I

Absorbance = Extinction coefficient x concentration x path length.

Basically says that the absorbance of a solution is proportional to the concentration of the absorbing solute and to the distance travelled by light through the sample.

It can be used to determine Hb conc in a sample using spectrophotometry results

9

Which is more negatively charged. HbA or HbS?

HbA is more negative

10

What causes the HbS mutation?

Single change of AA at position 6 in the protein from GLUTAMATE to VALINE (uncharged).

Occurs in beta chain