16.16 If three small beakers of water are lined up between the poles of a magnetic field,
explain what signals would be observed for a homogeneous field compared with an
inhomogeneous field.
16.17 How can MRI be used to reveal head trauma resulting from an accident?
16.18Calculate the resonance frequency of a free electron in a magnetic field poised at (a) 0.4 T
and (b) 0.3 T.
16.19 An EPR signal is observed at 0.3 T magnetic field for a 9 GHz microwave frequency. Calculate
the g-factor.
16.20 Explain quantitatively why radiofrequencies are used in NMR experiments, whereas
microwaves are used in EPR experiments.
16.21 An EPR spectrum is observed to be split into three equally spaced lines. What is the reason
for this splitting?
16.22 How does an EPR signal from an unpaired electron change due to coupling to a proton?
16.23How is the EPR spectrum of iron in a protein related to the oxidation state and coordination?
16.24 For Fe^2 +what is the value of the high-spin state?
16.25 For Fe^3 +what is the value of the low-spin state?
16.26 What EPR signals are observed from cytochromes?
16.27How is the EPR spectrum of iron in a protein related to the oxidation state and coordination?
16.28 What EPR signals are expected for an amino acid radical?
16.29 Ferredoxins are proteins that serve as electron carriers in cells. Ferredoxins contain a Fe 2 S 2
cofactor that is in a square configuration and coordinated to the protein by cysteine residues.
Predict what the EPR spectrum would look like.
16.30 Explain the origin of the EPR spectrum of ribonucleotide reductase.
16.31 Briefly explain the basic mechanism for the ribonucleotide reductase and the role of amino
acid radicals.
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(singke)
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