Shared Flashcard Set

Details

Hemoglobin Part 1
BioChem Fall 2016
40
Biochemistry
Undergraduate 3
10/07/2016

Additional Biochemistry Flashcards

 


 

Cards

Term
Describe 15. Does 2,3 BPG shift hemoglobin's curve to left or right?the nature of the peptide bond.
Definition
Short polymer of amino acids
Term
By convention, how do we always write proteins?
Definition
Left to right,
Begin w/ free -NH group and end w/ free -CO2 group
Term
1. What is the largest amino acid?
Definition
Tryptophan
Term
What is the smallest amino acid?
Definition
Glycine
Term
Which 9 amino acids can participate in H bonds? ( DONOR OR ACCEPTOR)
Definition
a. Tyrosine
b. Tryptophan
c. Arginine
d. Histidine
e. Glutamic Acid
f. Aspartic Acid
g. Serine
h. Threonine
i. Glutamine/Asparginine
Term
What five amino acids can participate in ionic bonds?
Definition
a. Aspartic Acid
b. Glutamic Acid
c. Lysine
d. Arginine
e. Histidine
Term
Which seven amino acids are considered to be completely nonpolar/hydrophobic?
Definition
a. Glycine
b. Alanine
c. Valine
d. Isoleucine
e. Leucine
f. Proline
g. Methionine
h. Phenylalanine
i. Tryptophan
Term
What is the only covalent bond that participates in tertiary/quaternary structure? What amino acid forms it? Under what conditions?
Definition
Disulfide bonds, formed by cysteine groups that are oxidized into one group.
Term
What force “causes” a protein to fold?
Definition
The Hhydrophobic effect
Term
What are domains?
Definition
independent functional units of the protein 100–200 amino acids long - encoded by a specific DNA sequence (exon)
Term
What is the difference between homotypic and heterotypic quaternary structures?
Definition
a. Homotypic- identical subunits
b. Heterotypic- association between subunits of different structures
Term
What are domains?
Definition
independent functional units of the protein 100–200 amino acids long - encoded by a specific DNA sequence (exon)
Term
What is the difference between homotypic and heterotypic quaternary structures?
Definition
a. Homotypic- identical subunits
b. Heterotypic- association between subunits of different structures
Term
Can any R group of the 20 a.a bind O2
Definition
Nope
Term
What metal do we use to bind oxygen?
Definition
Iron
Term
What redox state does iron have to be to bind oxygen?
Definition
Fe+2, ferrous, binds 02 reversibly
Term
Why isnt it advantageous to have free iron in our blood to bind oxygen?
Definition
Hydroxyl radicals(damaging to cell membranes and DNA
Term
What do we callmyoglobin that has iron in the incorrect redox state?
Definition
Ferric (+3)
Term
How many interactions does Fe make with heme?
Definition
6
Term
What is the function of myoglobin?
Definition
Oxygen storage of protein muscle
Term
12. What is meant by proximal vs distal Histidine when referring to myoglobin?
Definition
Proximal histidine has an Imidazole Nitrogen that is close enough to bond directly to the Fe2+ atom
b. Distal histidine is important for allowing binding of O2 to the Fe2+ atom
Term
What are the names of the subunits of hemoglobin?
Definition
a. Alpha
b. Beta
Term
2. Are the closest contacts between the two alpha or two beta subunits in hemoglobin, or between an alpha and beta subunit?
Definition
a. Alpha + beta
Term
3. Draw the oxygen dissociation curve for hemoglobin. What is its shape? What are the units on the axis?
Definition
[image]

b. More S- shaped sigmoidal
c. Read R to L because we are talking about how much Oxygen we are giving up
d. Read thru the tissues to see how much Oxygen has been delivered.
Term
How much more oxygen is released by hemoglobin to the tissues under exercise conditions compared to rest?
Definition
Rest:20-25%\
Excercise: 60-100%
Term
Define cooperative binding in terms of oxygen binding to hemoglobin
Definition
a. filling of the first O2 site increases the affinity of the remaining sites for O2 or losing a few O2’s makes it easier to lose more.
Term
What is the R state of hemoglobin? Does it have less or greater affinity for oxygen?
Definition
a. (relaxed) state corresponds to oxygenated form
b. Higher Affinity
Term
What is the T state of hemoglobin? Does it have less or greater affinity for oxygen?
Definition
a. T (tense) state corresponds to deoxy form, stablilizes increased O2 binding
b. Lower Affinity
Term
11. How does oxygen binding alter the state (T or R) of hemoglobin?
Definition
a. It changes from T to R thus increasing the O2 affinity
Term
[image]20. The partial pressure of oxygen in the venous blood of a human at rest at sea level is 40 torrs (40 mm).
a. What percentage of the oxygen originally bound to hemoglobin in the lungs remains unreleased? (use dissociation curve to read)
Definition
a. 70%
Term
b. Is the residual oxygen bound to hemoglobin under these conditions of any benefit? Explain
Definition
a. Yes, it is there to ensure if our metabolic rate changes immediately we still have O available to give up to that tissue.
Term
What are allosteric effectors?
Definition
a. Small molecules which bind to the protein at sites that are spatially distinct from the ligand binding site and exert either a positive or negative effect on ligand binding
Term
Does a drop in pH shift the curve to left or right?
Definition
Right
Term
Does an increase in pH shift the curve to left or right?
Definition
Left
Term
Where does CO2 bind on hemoglobin?
Definition
N- terminus amino groups
Term
9. How many CO2’s can bind to hemoglobin?
Definition
4via covalent attachment, nonenzymatic it can come on and off, binds @ the N terminus
Term
Do carbamate groups stabilize T or R state?
Definition
R state
Term
11. Does an increase in CO2 shift the curve to left or right?
Definition
Right
Term
13. What is 2,3 BPG?
Definition
a. Negative heterotropic effector
Term
Does 2,3 BPG shift hemoglobin's curve to left or right?
Definition
Right
Supporting users have an ad free experience!