Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CP Test 3 > B4-024 Myoglobin and Hemoglobin in Medicine > Flashcards

B4-024 Myoglobin and Hemoglobin in Medicine Flashcards

1
Q

what is myoglobins quaternary structure?

A

monomer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is hemoglobins quaternary structure?

A

tetramer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

myoglobin and hemoglobin moonlight in the conversion of

A

nitric oxide to nitrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

prosthetic group shared by both

A

heme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

why does the heme prosthetic group need to be bound to proteins?

2 reasons

A
  1. free heme binds CO more tightly than O2
  2. O2 oxidizes the iron in free heme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

the observed binding curve of hemoglobin is sigmoidal, indicating

A

cooperativity and multiple binding sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

RBCs have a high concentration of […] allowing for the binding of many hemoglobin molecules

A

BPG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

excess BPG shifts the equilibrium to

A

deoxyHb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

excess O2 shifts the equilibirum to

A

OxyHb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

BPG preferentially binds to

A

deoxyHb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

the Bohr effect

A

as pH decreases O2 affinity lowers

excess H+ and CO2 signal tissues need more oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

H+ ions […] O2 binding

A

weaken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Co2 […] O2 affinity

A

lowers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

CO2 binds covalently and reversibly at

A

N terminal amines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

without BPG, what happens to Hb curve?

A

cooperativity is lost

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

BPG is upregulated with

A

hypoxia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

BPG is lost during the

A

shelf life of blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how does increased BPG affect the binding curve?

A

shifts right

  • decreased affinity
  • allows oxygen to release more readily to tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

BPG does not bind well to fetal hemoglobin, What’s the benefit of this?

A
  • increased affinity for O2
  • easier for fetus to get oxygen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how do high altitudes alter binding affinity?

A

decreased

curve shifts to right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

some OTC topical anesthetics oxidize

A

Fe2+ to Fe3+

cannot bind oxygen, maybe cause of SIDS

22
Q

effects of metheoglobinemia on binding curve?

A

cannot reach saturation

  • limits oxygen able to carry
  • doesn’t affect midpoint
23
Q

antidote for methemoglobinemia

A

methylene blue

24
Q

CO has an [….] affinity for heme

A

extremely high

25
Q

substoichiometric effects of CO on Hb

A

1 CO molecule takes up 1 binding site and increases affinity for O2

  • can’t carry as much O2
  • can’t release O2
26
Q

loss of a Hb subunit, results in aggregation of abnormal proteins and anemia

A

thalassemia

27
Q

How does Hb Kansas affect the binding curve?

A
  • decreased cooperativity
  • decreased affinity
  • shifts midpoint right
28
Q

this hemoglobinopathy results in an unstable protein that dissociates, reducing the amount of Hb available for transport

A

Hb Kansas

29
Q

mutation causing Hb Kansas

A

beta Asn102Thr

30
Q

free Hb can cause extreme vasocontriction via

A

consumption of NO converting it to nitrate

31
Q

dimerization of free Hb causes

A

kidney damage

32
Q

oxidation of free heme causes

A

increased ROS

33
Q
  • synthetic Hb from cross-linked human Hb
  • trialed in trauma setting
  • raised ethical concerns
A

polyheme

34
Q
  • synthetic Hb made from cow Hb
  • KUMC used this successfully to treat Jehova’s witness
A

hemopure

35
Q

normal adult Hb is composed of

A

2 alpha
2 beta subunits

36
Q

oxygenated Hb has a […] affinity for O2

A

high

37
Q

deoxygenated Hb has a […] affinity for O2

A

low

promotes release/unloading

38
Q

the protein component of Hb acts as a buffer for

A

H+ ions

39
Q

myoglobin has a […] affinity for oxygen than Hb

A

higher

40
Q

myoglobin is composed of

A

a single polypeptide chain with one heme group

41
Q

Hb substitutes need to reduce the […] that leads to a blood pressure spike

A

NO di-oxygenation reaction

decrease affinity for NO, increase Kd for NO

42
Q

the relationship between Kd and affinity is

A

inverse

43
Q

reduced affinity shifts the curve

A

right

44
Q

increased affinity shifts the curve

A

left

45
Q

BPG allosterically […] the affinity of Hb for O2

A

lowers

46
Q

proton binding […] the affinity and [….] pH

A

lowers
lowers

47
Q

what causes methemoglobinemia?

A

nitrates

oxidize the Hb iron to Fe3+

48
Q

a left shifted O2 binding curve indicates

A

increased affinity

49
Q

allosteric mechanisms for lowering O2 binding affinity

2

A
  • Bohr effect
  • CO2 toxicity
50
Q

BPG preferentially binds the

A

deoxy Hb

allows more oxygen to tissues

CP Test 3 (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions