Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biological Chemistry > Protein Structure > Flashcards

Protein Structure Flashcards

1
Q

What are the 2 functions of Red Blood Cells?

A
  • transfer O2 from lungs to tissue

- transfer CO2 from tissue to lungs

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

What were the first proteins to be crystallised?

A

Haemoglobin and Myoglobin

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

How were Haemoglobin and Myoglobin studied?

A

via ultracentrifugation

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

Where is myoglobin found in vertebrates?

A
  • skeletal muscle

- heart muscle

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

How many subunits does myoglobin have?

A

1

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

What does myoglobin facilitate?

A

rapidly respiring muscle tissue

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

Is the rate of O2 diffusion slow?

A

Yes

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

Why is the rate of O2 diffusion slow?

A

due to the solubility of O2

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

Does myoglobin increase or decrease the solubility of O2?

A

increase

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

Why is oxygen storage via myoglobin greater in whales and seals?

A

they can slowly release O2 in their bodies

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

What is the structure of the “haem complex” in myoglobin?

A

two histidine residues (proximal and distal) anchor to haem

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

What is the ring around Fe called?

A

polyporphyrin

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

What is “Histidine”?

A

an amino acid with a side chain (imidazole)

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

What does “Histidine” have a tendency of binding?

A

metal

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

What genes encode haemoglobin?

A

globin

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

How many subunits does haemoglobin have?

A

4 (2 alpha, 2 beta)

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

What type of oligomer is haemoglobin?

A

tetramer

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

What is an “oligomer”?

A

a molecule consisting of a few similar repeating units

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

What protein contains iron?

A

ferritin

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

Is the synthesis of haem and globin synchronised?

A

yes

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

Where is haem synthesised?

A

mitochondria

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

Where is globin synthesised?

A

polyribosomes

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

Do what do mature red blood cells not contain?

A

mitochondria

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

What does Hb carry excluding O2?

A
  • CO2

- H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is haem derived from?
protoporphyrin IX
26
Can Fe3+ bind O2?
No
27
What is the reduced form of iron?
Fe2+
28
What is the oxidised form of iron?
Fe3+
29
What is Fe3+ bound to globin?
methemoglobin
30
What number ligand does protoporphyrin bind O2 to?
6th
31
What is the 5th ligand?
histidine F8
32
What bound to the proximal side of Fe2+?
His F8
33
What bound to the distal side of Fe2+?
oxygen
34
What 4 molecules outcompete O2?
- CO - NO - CN- - H2S
35
What can increased methemoglobin be caused by?
- drugs | - environmental agents
36
What does the oxygen dissociation curve of Mb and Hb look like?
compare to reference image
37
What is the | binding of O2 abbreviated as?
YO2
38
What is the formula of YO2?
PO2/ Kd+pO2
39
What do the Hb subunits independently compete for?
the first O2 to bind
40
What does it mean if YO2 is close to 1?
3 subunits are occupied and the 4th is independent of the other site
41
What is "D-2,3-Bisphosphoglycerate (BPG)"?
- allosteric effector
42
What is the function of "D-2,3-Bisphosphoglycerate (BPG)"?
- modulates (regulates) the affinity of Hb for O2 | - providing control and adaptation to environmental factors
43
What does high altitude mean for the abundance of BPG?
increased
44
What is "BPG" also known as?
DPG
45
What 4 factors affect the position of Hb-O2 dissociation curve?
- [BPG] - pH - CO2 in RBCs (Bohr effect) - structure of Hb
46
What is "stripped Hb"?
Hb without BPG
47
How is "stripped Hb" produced?
conc. NaCl
48
What causes a right shift in the dissociation curve?
- high BPG - high H+ - high CO2 - HbS (Sickle Cell)
49
What does a right shift mean?
easy O2 delivery (improves release of O2)
50
What causes a left shift in the dissociation curve?
- low BPG | - HbF (fetal Hb)
51
What does the "picket-fence Fe(II)-porphyrin complex" mean?
Fe2+ bound within the porphyrin ring is surrounded | by side-chains of the porphyrin molecule to form a “fence” like structure that protects the iron from oxidation
52
Can oxygen bind to tense Hb?
not well
53
What binds to tense Hb?
- CO2 | - H+
54
What is the maximum capacity of Hb for O2?
4
55
Where are the interactions between the alpha and beta subunits occurring in DeoxyHb?
alpha1/beta1
56
Where are the changes between the alpha and beta subunits occurring in oxyHb?
alpha1/beta2
57
What subunits are unchanged in oxyHb (relaxed form)?
alpha1/beta1
58
What occurs when oxygen binds to Hb?
conformational shape change
59
How does Hb go from T state to R state?
binary switch
60
What drives the T->R transition?
energy in the formation of Fe-O2
61
As the lungs become more acidic, what does it mean for O2?
it does not bind as well
62
At higher pH (basic) what is promoted?
tighter binding of O2 to Hb
63
At lower pH (acidic) what is promoted?
easier release of O2 from Hb
64
What is the equation linking the Bohr effect and CO2?
CO2 + H20 HCO3- + H+
65
What enzyme catalyses this reaction in erythrocytes?
carbonic anhydrase
66
How does HCO3- affect the pH?
increases
67
What does the increased pH do to HCO3-?
decreases the binding of O2
68
What does the decreased binding of O2 mean for Hb?
it's in T form
69
Where is the forward reaction (CO2 + H20->HCO3- + H+) driven?
capillaries
70
Where is the backward reaction (HCO3- + H+-> CO2 + H20) driven?
lungs
71
What does deoxyHb bind CO2 as?
carbamate
72
High [CO2] in capillaries stimulates Hb to what?
release O2
73
What other ion affects the affinity of Hb for O2?
Cl-
74
What is Sickle Cell Anaemia (SCA)?
a genetic disease that affects Hb
75
What individuals are affected (diseased) by SCA?
homozygous
76
What individuals are not affected (carriers) by SCA?
heterozygous
77
What does SCA cause?
defective Hb (they stick together causing RBCs damage)
78
Heterozygous individuals are protected from what? (By having SCA)
malaria
79
What DNA mutation occurs in HbS?
point mutation
80
What does the mutation cause in HbS?
glutamate (glu) replaced by valine (val)
81
Why is this protein mutation drastic?
glu is negatively charged, val has no charge
82
Is Val is hydrophobic or hydrophilic?
hydrophobic

Biological Chemistry (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions