FT IR Spectroscopy – Section 1

1. Which of the following is the basis of the first dimension of separation for two-dimensional electrophoresis?

A. Molecular mass
B. Solubility
C. Isoelectric point
D. Folding

Correct Answer: C. Isoelectric point

2. What is meant by the rotating frame of reference?

A. That the sample is spun rapidly in the applied field
B. If the laboratory itself is imagined to be rotated at the Larmor frequency, viewing that individual magnetic moment vectors are fixed in space
C. That the detector rotates around the sample
D. None of the above

Correct Answer: B. If the laboratory itself is imagined to be rotated at the Larmor frequency, viewing that individual magnetic moment vectors are fixed in space

3. The sequence of amino acids in proteins can be determined by means of

A. identification of the -NH2 terminal amino acids
B. identification of the -COOH terminal amino acids
C. partial cleavage of the original polypeptide into smaller polypeptides
D. all of the above

Correct Answer: D. all of the above

4. Why is it advantageous to record many FID signals from the same sample and then add them together?

A. To ensure that all target nuclei in the sample have been excited
B. To remove inaccuracies caused by fluctuations in the applied magnetic field
C. To increase sensitivity
D. None of the above

Correct Answer: C. To increase sensitivity

5. In FT-NMR, how are nuclei excited?

A. By radio-frequency radiation whose frequency is swept across a predetermined range
B. By an intense pulse of radiation which contains a wide range of frequencies
C. By an intense pressure
D. None of the above

Correct Answer: A. By radio-frequency radiation whose frequency is swept across a predetermined range

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