Chapter 7 Review Flashcards
In terrestrial animals, myoglobin…
- Increases O2 solubility
- Promotes O2 diffusion into tissue
In marine animals, myoglobin…
- Promotes O2 diffusion
- 10x amount of Mb present
- Functions in O2 storage
Structure of the Sperm Whale myoglobin was discovered by ___________. It was the first _____ of a protein.
John Kudrow (1959) ; protein crystallography
Myoglobin is known for two important jobs
1) Binding and releasing O2
2) Helps diffuse CO2 throughout the body
Sperm Whale myoglobin is a ___ protein. It has a total of _________. Heme (protoporphyrin 9). Fe(II) is the metal in the middle. Contains ________ and _________.
Pyroles and histidine residues
What is the proximal histidine?
The histidine attached to the Fe atom
Can Fe (II) convert to Fe (III)?
Yes, when Fe(II) becomes Fe(III), this means that an e- is lost. Once Fe (III) is formed, it can’t bind to oxygen and myoglobin is not useful anymore.
The protein _________the heme _______ and non-oxygen things.
protects ; from oxidation
Ka is __________ to Kd.
inversely proportional
Why do partial pressure values matter?
Pressure helps dissolve O2 into the blood.
YO2 = (PO2)/(Kd+pO2)
Dalton’s Law of Partial Pressure
YO2 vs. PO2 hyperbolic curve means
myoglobin binding
The greater the partial pressure, the ________ the solubility.
greater
Fraction bond is equal to _____.
Dissociation constant
Lower affinity for oxygen on a myoglobin partial pressure graph will cause the graph to
move to the right and become more shallow
The quaternary structure of hemoglobin is ________.
heterodimer
Oxygenation of a heme group means
oxygen is binding to the heme group
When Fe(II)-heme complex is oxygenated
- The electronic state is altered
- The color changes from dark purple to red.
Define fractional saturation
the O2 dissociation of myoglobin. The fraction of O2-binding sites occupied by O2. (Value ranges from 0 ,or no O2 bound, to 1, or all the binding sites of all the myoglobin molecules are occupied)
low pO2 of myoglobin means
little O2 binds to the myoglobin
high pO2 of myoglobin means
virtually all O@_BINDING SITES ARE OCCUPIED> Myoglobin is saturated with O2.
As pO2 of myoglobin increases, ______ O2 binds to the myoglobin.
more
p50
the oxygen pressure at which myoglobin is 50% saturated
p50 of myoglobin
2.8 torr
Myoglobin brings oxygen to the ________ of ________ cells.
capillaries ; muscle
Hemoglobin is a _____. It has ____ C2 symmetry and ____ symmetry.
α2β2 tetramer ; exact ; pseudo-D symmetry
Hemoglobin has a _______ quaternary structure.
heterodimer
Hemoglobin is made of _____ subunits: 2 _ and 2 _
4 ; α ; β
When oxygen binds to hemoglobin, the ______ of hemoglobin changes.
structure
T-State
Deoxy hemoglobin, low affinity for oxygen
R-State
Oxy hemoglobin, high affinity for oxygen
_____ degree rotation causes R-state to go back to T-state.
15
Hemoglobin partial pressure curve is ______.
Sigmoidal
Define cooperativity.
- The proteins “work” together.
Define allosteric effect
A small molecule whose binding to a protein affects the function of another site on the protein.
In hemoglobin, _____ prevents the release of oxygen.
cooperativity
____________ transports the oxygen from the hemoglobin to the cell.
myoglobin
What prevents veins busting from the built up pressure from CO2 when exercising?
carbonic anhydrase promotes the forward reaction of CO2 + H2O H+ + HCO3-
At higher pH, hemoglobin _______ its oxygen
releases
What is Allostery?
Communication between subunits.
Symmetry Model of Allosterism
- T-state and R-state are always talking back and forth. They are in the same state.
- A model of allosteric behavior in which all subunits of an oligomeric protein are constrained to change conformation in a concerted manner so as to maintain the symmetry of the oligomer.
Sequential Model of Allosterism
- T-state goes to R-state and reverse.
- A model of allosteric behavior in which the subunits of an oligomeric protein change conformation in a stepwise manner as the number of bound ligands increases.
A normal RBC has Pro-Glu-Glu. A sickle-cell RBC will have the mutation __________.
Pro-Val-Glu
Vaccines stimulate _____.
T-cells
Antibody response is part of the _______ immune response.
humoral
Antibodies (aka immunoglobins) have ________ bonds. ___ C-termini. 2 _____chains and 2 _______ chains.
Disulfide bonds ; 4 ; heavy and light
Fab
“Arms” of the antibody. Antigen binding; variable binding region (antigen coded by hypermutatable region.
What is Neutralization in immunology?
Antibodies surround the antigen to prevent the virus from binding to the host cell.
