Discussion Questions — Part F 587 



around the critical point. What is the advantage of this ? What types of 

 results are obtained by this method ? Cite specific examples. 



11. Describe the replica method for the preparation of electron microscope 

 samples. Give examples of its use. 



12. The analog computer X-RAC was referred to in Chapter 31. Des- 

 cribe this computer briefly, including an indication of the theoretical basis 

 and of analogies used. 



13. Electron spin resonance was described in Chapter 28. Proton spin 

 resonance is also used for biological studies. Describe one of these. 



14. Describe the preparation and use of radioactive sodium isotopes. Give 

 specific examples of their use in biological studies. 



15. Describe the preparation and use of a radioactive isotope of sulfur. 

 Give specific examples of its use in biological studies. 



16. What are Raman spectra? How can they be observed? What 

 applications do they have to biological problems? 



17. What is meant by the term "fluorescence?" Describe the necessary 

 apparatus for observing it quantitatively. Cite several examples where this 

 type of observation has been used in biological studies. 



18. What is the nature of the evidence for free radicals in laccase reactions ? 



19. Outline the mathematical theory necessary to find molecular orbitals 

 for tetrapyrrole ring structures. 



20. Describe the technique of column chromatography. What is its 

 physical basis? 



