Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Hemoglobin, Myoglobin and oxygen transport > Flashcards

Hemoglobin, Myoglobin and oxygen transport Flashcards

1
Q

Functions of globular proteins (5)

A

Storage of ions and other molecules
Transport of Ions and molecules
Defense against pathogens
Muscle contraction
Biological catalyst

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

Do proteins bind with ligands through irreversible reactions or reversible?

A

Reversible

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

Are binding sites specific to each ligand?

A

Yes

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

What is ligand binding coupled to conformational changes called?

A

Induced fit

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

What is it called when conformational changes in one subunit can affect the others

A

Cooperativity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Are the interactions in binding sites with ligand covalent bonds?

A

No, the bonds are non covalent

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

Do ligands typically bind on the surface of a protein?

A

No they typically find their binding sites in cavities

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

Model of specificity ligand binding?

A

Lock and key model
Induced fit

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

What are the 4 characteristics of complementarity of the ligand and binding site?

A

Size
Shape
Charge
Hydrophobic/hydrophilic character

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

What is induced fit?

A

When ligand bind to protein there is a conformational change

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

What is lock and key?

A

Protein and ligand fit together perfectly

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

What are interactions between ligand and protein mediated by?

A

Induced fit

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

What can interactions between ligand and proteins regulated by?

A

Activator or inhibitor

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

What are things that induce change in protein conformation called?

A

They are allosteric

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

Can ligands help each other change the shape?

A

Yes it is comparitivity

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

How many subunit are myoglobin?

A

1

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

How many subunits are haemoglobin?

A

4

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

How many alpha subunits in haemoglobin?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How many beta subunits in haemoglobin?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Do alpha and beta subunit in haemoglobin interact which each other across both alpha and beta and beta and beta and alpha and alpha?

A

They across with each other all permutations with different surfaces

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

What is a dalton?

A

The weight of a hydrogen atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the kilodalton?

A

The standard unit used to represent the weight of large molecules such as proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Where does haemoglobin have to pick up oxygen?

A

In a place with high partial pressure of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Where does haemoglobin have to release oxygen?

A

In a place with low partial pressure of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the prostetic group of haemoglobin?

A

Heme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Do protein have a naturally affinity for oxygen?

A

No the need the prosthetic group heme to do so

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does myoglobin do?

A

Store oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Where is myoglobin found?

A

In the muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

How many helixes in myoglobin?

A

9 (labelled a-h)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Is Heme a ligand?

A

No it is a prosthetic group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is responsible for the conformational change when the oxygen is bound? (haemoglobin and myoglobin)

A

The proximal and distal histidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the two important histidines in haemoglobin and myoglobin? and what do they bind with?

A

Distal bind with oxygen and proximal bind with Iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What part of the heme holds the central iron ion?

A

The porphyrin ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Would the protein function without the prosthetic group?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What are the two confirmation of the heme?

A

Tense state and relaxed state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

When is the tense state of heme?

A

No oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

When is the relaxed state of heme?

A

With oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Does the other subunits change conformation when oxygen binds to one?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What happens to iron when oxygen bind?

A

Its pushed into the plane of the heme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Could myoglobin transport oxygen?

A

No it wouldn’t be good because the partial pressure would have to be very low… So it would have problems releasing it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Does myoglobin bind well to oxygen at low partial pressure?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Where is CO2 bound in haemoglobin?

A

On the protein chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Does pH change the affinity of binding with oxygen?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is carbon monoxide for a heme?

A

Almost irreversible ligand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Does heme have a higher affinity for oxygen or carbon monoxide?

A

Carbon monoxide by A LOT (carbon monoxide poisoning)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Why can the affinity for oxygen change?

A

It’s a multiple binding site and they interact with each other because of positive cooperativity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is the main difference between fetal and adult haemoglobin?

A

Has higher affinity for oxygen because the nature of the exchange between mother and fetal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

How many coordination bonds does iron have?

A

6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Does the magnetic properties change when the heme iron moves into the plane of the protoporphyrin?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Where does biphosphoglycerate come from?

A

Glycolosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Where is the 2,3-bisphosphoglycerate found?

A

In the central cavity of haemoglobin

52
Q

What is the Bohr effect?

A

When blood plasma pH decreases the haemoglobin has less affinity for O2

53
Q

Which binds better to heme O2 or CO?

A

CO

54
Q

How does the distal histadine effect the CO affinity of heme?

A

Makes it less

55
Q

What is hypoxia?

A

Low availability of O2 in a tissue

56
Q

How does sickle cell disease effect your chances of malaria?

A

Lowers the chances

57
Q

What does the non covalent binding of ligand to binding site ensure?

A

That the binding is reversible

58
Q

Are the interactions between ligand and protein strong or weak?

A

Weak

59
Q

What does it mean when 2 ligands bind cooperatively to a protein?

A

When the ligands help eachother to bind to the protein

60
Q

What is induced fit mediated by?

A

Weak interactions

61
Q

What is an allosteric?

A

Anything that induces changes in the conformation of proteins

62
Q

Can humans transport oxygen as is?

A

No we need facilitation for transporting it

63
Q

2 main proteins in red blood cells

A

Hemoglobin
Carbonic anhydras

64
Q

What stores oxygen in the tissues?

A

Myoglobin

65
Q

What transports oxygen in the blood?

A

Haemoglobin

66
Q

Which is the standard unit to measure proteins in?

A

Kilodalton

67
Q

What is a prosthetic group on of proteins?

A

A non amino acid component

68
Q

Ferrous state of iron

A

Fe2+

69
Q

Ferric state of iron?

A

Fe3+

70
Q

In which state of iron does oxygen bind?

A

Ferrous

71
Q

What does heme bind better, oxygen or monoxide?

A

Monoxide

72
Q

What is the amount of O2 in solution directly proportional to?

A

The partial pressure

73
Q

What is the prosthetic group of haemoglobin?

A

Heme

74
Q

Which proteins are oxygen binding?

A

Globins

75
Q

What would happen if transitions metals bind O2 while free in solution?

A

They would form free radicals

76
Q

How many oxygen molecules can haemoglobin bind?

A

4

77
Q

How many oxygen molecules can myoglobin bind?

A

1

78
Q

What are the interactions between the subunits in haemoglobin?

A

Hydrophobic
Hydrogen bond interactions

79
Q

How much of the total blood transported in blood is bound by haemoglobin?

A

98%

80
Q

How many coordinate binding does the iron in heme have?

A

6

81
Q

Where does iron bind in heme?

A

4 bonds with nitrogen of the porphyrin rings
1 bond with proximal histidine
1 bond with oxygen

82
Q

What happens if iron is not ferrous?

A

If there is a reduction you can have a super oxide which is a reactive oxygen species which is extremely toxic

83
Q

Mechanism of cooperative in haemoglobin

A

When oxygen binds to heme it causes a conformational change that are relevant to the structure and function of haemoglobin

84
Q

Which state is haemoglobin in when the blood is in the lungs?

A

Relaxed because the oxygen concentration is high

85
Q

Which state is haemoglobin in when the blood is in the tissue?

A

Tense because the oxygen concentration is low

86
Q

What allows the haemoglobin to release oxygen in the tissue when needed?

A

The tense state

87
Q

What happens to the position of the iron when oxygen is added?

A

It is changed which transmit a change to the histidine and the rest of the subunits

88
Q

What does the position of the iron change to when oxygen is added?

A

It is moved to be planar with porphyrin

89
Q

Shape of heme before oxygen binds

A

Domed (nonplanar)

90
Q

Shape of heme after oxygen binds

A

Planar

91
Q

What pulls iron out of plane?

A

The proximal histidine

92
Q

What does the concerted model theorise that happens when one oxygen molecule binds?

A

The change is transferred to all other subunits (all or nothing model)

93
Q

What does the sequential model theorise that happens when one oxygen molecule binds?

A

The change happens step for step

94
Q

Is the structure of heme the same in myoglobin and haemoglobin?

A

Yes

95
Q

Why would myoglobin be a bad oxygen transporter?

A

Because it has problems releasing the oxygen

96
Q

What is the X axis in a saturation curve?

A

pO2 (kPa)

97
Q

What is the Y axis in a saturation curve

A

Saturation index (0 is no oxygen bound, 1 is 100% oxygen bound)

98
Q

What kind of shape is the haemoglobin saturation curve?

A

Sigmoid

99
Q

What kind of shape is the myoglobin saturation curve?

A

Hyperbolic

100
Q

What does the sigmoid curve indicate?

A

Cooperativity

101
Q

When is myoglobin used?

A

When the concentration of oxygen in muscles is very low

102
Q

Does changes in pH have an effect on binding of oxygen in haemoglobin?

A

Yes

103
Q

At what pH is haemoglobin affinity for oxygen lower?

A

At lower pH

104
Q

What is positive cooperativity?

A

First binding event increases affinity at remaining sites (sigmoid curve)

105
Q

What is negative cooperativity?

A

First binding event reduces affinity at remaining sites

106
Q

How is the haemoglobin in the foetus different?

A

It has 2 alpha subunits and 2 gamma chains
It tends to keep the oxygen and not release it

107
Q

How is the binding curve of a foetus?

A

Less sigmoidal as it doesn’t need to release the oxygen

108
Q

2 models of cooperativity

A

Concerted
Sequential

109
Q

Which model of cooperativity is all or nothing?

A

Concerted

110
Q

Which model of cooperativity is step for step?

A

Sequential

111
Q

When is allosteric regulation homotropic?

A

When the ligand is also the allosteric regulator

112
Q

When is the allosteric regulation heterotrophic?

A

When the ligand and the allosteric regulator are 2 different molecules

113
Q

Is the allosteric regulation of haemoglobin homotropic or heterotrophic?

A

Homotropic

114
Q

Which state of haemoglobin is more stable?

A

T sate

115
Q

Which state of haemoglobin has more interactions?

A

T state

116
Q

What does the binding of oxygen trigger a conformational change from and to?

A

From T to R

117
Q

Where is the ion pairs that are broken when haemoglobin change from T to R state found?

A

Between the alpha1 and beta2 interface

118
Q

Are the non covalent bonds in deoxygenated and oxygenated haemoglobin the same?

A

No they differ

119
Q

Why do deoxygenated and oxygenated haemoglobin have different non covalent bonds?

A

Because the amino acids that interact and bind in them are different

120
Q

Why does fetal haemoglobin have a higher affinity for oxygen?

A

Because beta chains are substituted for gamma chains

121
Q

What is the difference between the beta and gamma chains in haemoglobin?

A

In position 143 gamma chains have Serine residue while beta has histidine residue

122
Q

Which has a higher affinity for oxygen, fetal or adult haemoglobin?

A

Fetal

123
Q

What does the fact that the foetus can stay without oxygen for longer make it resistant to?

A

Hypoxia

124
Q

What ensures that the oxygen is transferred to the foetus from the maternal blood across the placenta?

A

The fact that it has a higher affinity for oxygen

124
Q

Why is the PO2 in fetal tissue very low?

A

Because of the high metabolic rate associated with fetal growth rates

125
Q

When is the fetal haemoglobin replaced with adult haemoglobin?

A

At birth

125
Q
A

Biochemistry (28 decks)

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