Comparing curves for simple versus cooperative binding
1. Hemoglobin is a conjugated protein, while myoglobin is not. True or False
2. The T and R conformations of Hb: ______________ (write letters of all that apply on the line provided above)
a. are in equilibrium with deoxy-Hb
b. interconvert in response to the binding and release of oxygen
c. interconvert in a sequential manner
d. are each stabilized by specific weak interactions between a and b chains
e. have different affinities for oxygen
3. Depletion of 2,3-bisphosphoglycerate from red blood cells would result in oxygen starvation due to :____ (write letter of best choice on the line provided)
a. impaired binding of oxygen by Hb in the lungs
b. impaired binding of oxygen by Mb in muscle tissue
c. impaired release of oxygen by Hb in the peripheral tissues
d. Acceleration of glycolysis
Functions and phases
Cigarette smoking introduces nicotine into the body, which in turn leads to raised internal levels of dopamine, a chemical linked to addictive behaviors. Recent studies found that an enzyme important in the degradation of dopamine (called monoamine oxidase B, MAO B) was 40% less active in smokers. (Scientific American, May 1996)
1. Assuming that MAO B is a regulated, multisubunit protein, nicotine is thus a ______________ effector in dopamine metabolism, specifically, the _____________ pathway.
2. If nicotine were also a positive effector in dopamine synthesis, draw a metabolic pathway for dopamine, including the effects of nicotine.
Triose phosphate isomerase catalyzes the conversion of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate. The standard free energy change for this reaction is +7.6 kJ/mol. However, the observed free energy change for this reaction in erythrocytes is +2.4 kJ/mol.
1. Calculate the ratio of [DHAP]/[G-3-P] in erythrocytes from DG.
2. If [DHAP] = 0.2 mM, what is [G-3-P]?
History and overview of the10 steps
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