BMSC 200 Module 5 Protein Function
Exam Questions and Answers
Heme prosthetic group - ANSWER-consists of protoporphyrin and an iron (II) ion.
carbon monoxide - ANSWER--similar molecular structure as O2
- exerts deadly effects by competing with oxygen for binding to heme
- CO binds heme with 200 times greater affinity than O2
myoglobin structure - ANSWER-- teriary structure
- single sub-unit
- with single heme group, can bind one oxygen molecule
- small globular protein consisting of a single polypeptide of 153 residues arranged in
8 alpha-helicies
hemoglobin structure - ANSWER--4 subunits
-quarternary structure
- with four heme groups, can bind four oxygen molecules
- each subgroup closely resembles myoglobin
myoglobin oxygen binding - ANSWER-- higher affinity for oxygen than hemoglobin
- has a hyperbolic curve of oxygen binding, indicating single O2 binding constant
- amount of )2 required to half saturate the protein is quantified by P50 (3 torr)
hemoglobin oxygen binding - ANSWER-- binding of oxygen by hemoglobin displays
sigmoidal behavior
- indicates coopertivity of oxygen binding
myoglobin fraction saturation - ANSWER-fraction of myoglobin saturated with
oxygen at a given partial pressure of oxygen is calculated by:
theta = [pO2] / ([pO2] + [P50])
hemoglobin oxygen transport - ANSWER-- hemoglobin contained within erythrocytes
(red blood cells)
- hemoglobin is an allosteric protein whose oxygen affinity is regulated through
various physiological signals
allosteric proteins have __ and __ forms - ANSWER-T (inactive) and R (active)
- these T and R forms are in rapid equilibrium
a protein with ____ oxygen binding affinity would saturate effectively with O2 in lungs
but not release to tissues - ANSWER-high
Exam Questions and Answers
Heme prosthetic group - ANSWER-consists of protoporphyrin and an iron (II) ion.
carbon monoxide - ANSWER--similar molecular structure as O2
- exerts deadly effects by competing with oxygen for binding to heme
- CO binds heme with 200 times greater affinity than O2
myoglobin structure - ANSWER-- teriary structure
- single sub-unit
- with single heme group, can bind one oxygen molecule
- small globular protein consisting of a single polypeptide of 153 residues arranged in
8 alpha-helicies
hemoglobin structure - ANSWER--4 subunits
-quarternary structure
- with four heme groups, can bind four oxygen molecules
- each subgroup closely resembles myoglobin
myoglobin oxygen binding - ANSWER-- higher affinity for oxygen than hemoglobin
- has a hyperbolic curve of oxygen binding, indicating single O2 binding constant
- amount of )2 required to half saturate the protein is quantified by P50 (3 torr)
hemoglobin oxygen binding - ANSWER-- binding of oxygen by hemoglobin displays
sigmoidal behavior
- indicates coopertivity of oxygen binding
myoglobin fraction saturation - ANSWER-fraction of myoglobin saturated with
oxygen at a given partial pressure of oxygen is calculated by:
theta = [pO2] / ([pO2] + [P50])
hemoglobin oxygen transport - ANSWER-- hemoglobin contained within erythrocytes
(red blood cells)
- hemoglobin is an allosteric protein whose oxygen affinity is regulated through
various physiological signals
allosteric proteins have __ and __ forms - ANSWER-T (inactive) and R (active)
- these T and R forms are in rapid equilibrium
a protein with ____ oxygen binding affinity would saturate effectively with O2 in lungs
but not release to tissues - ANSWER-high
