CHEM-342 Introduction to Biochemistry                     Group Members________________________
Mid-term Examination - Group Part
Wednesday, 27 March 2002
H. B. White - Instructor

Important - Please read this before you turn the page.

1. (9 Points) Zinoffsky carefully determined the empirical formula for horse hemoglobin in 1886. From that formula, one can calculate a minimum molecular weight of 16,700, a number mentioned both by Conant and by Svedberg and Fåhraeus in the mid 1920's. Knowing what is now known about hemoglobin structure, would it have been possible for anyone to get an empirical formula that matched the molecular formula for hemoglobin using the methods of Zinoffsky? Explain your reasoning.

2. (8 Points) Draw a diagram depicting the forces acting on a hemoglobin molecule spinning in Svedberg's centrifuge. Describe your diagram in words and formulas as needed.

3. (8 Points) In his electrochemical titrations, Conant observed that that the oxidation-reduction potential he calculated for hemoglobin varied as a function of pH within certain ranges and depended on whether oxygen, carbon monoxide, or no ligand was attached to the iron. Conceptually, why does pH or ligand binding have any effect on the reduction potential of hemoglobin?

(5 Point Bonus) The arterial blood of a typical college student contains about 16g of oxyhemoglobin per 100ml. Estimate how many ml of oxygen per 100ml of blood does that represent at standard temperature and pressure? (Note: Estimation does not require a calculator. Any answer within a factor of 2 is correct. Show work for credit.)

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Last updated: 28 March  2002 by Hal White
Copyright 2002, Department of Chemistry and Biochemistry, University of Delaware