Quiz
Lecture Tutorial 2 - Myoglobin and Haemoglobin
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Questions in this quiz (19)
1Which of the following is CORRECT
- AHaemoglobin and myoglobin are not a part of the same family
- BHaemoglobin is a homotetramer
- CMyoglobin displays co-operativity
- DIn haemoglobin the hydrophobic cleft within the globin contains the haem group
2Which of the following is CORRECT concerning Haemoglobin
- AThe haem is the non protein part consisting of 4 pyrrole rings joined by methene bridges with a central Fe that has 6 co-ordination sites
- BThe haem is the protein part consisting of 6 pyrrole rings joined by methene bridges with a central Fe that has 4 co-ordination sites
- CThe haem is the non protein part consisting of 6 pyrrole rings joined by methene bridges with a central Fe that has 4 co-ordination sites
- DThe haem is the protein part consisting of 4 pyrrole rings joined by methene bridges with a central Fe that has 6 co-ordination sites
3Which of the following is INCORRECT concerning oxygenated Haemoglobin
- AFour of the co-ordination sites of the central Fe2+ are taken up by bonds to nitrogen from the pyrrole rings
- BOne of the co-ordination sites of the central Fe2+ is taken up by an oxygen
- COne of the co-ordination sites of the central Fe2+ is taken up with a strong covalent bond to a proximal HisF8
- DOne of the co-ordination sites of the central Fe2+ is taken up by a bond with a distal HisE7
4Which of the following is CORRECT
- AThe distal HisE7 prevents linear configuration of the O2 molecule via a hydrogen bond to ensure easy dissociation
- BThe proximal HisF8 prevents linear configuration of the O2 molecule via a hydrogen bond to ensure easy dissociation
- CThe distal HisE7 prevents linear configuration of the O2 molecule via a strong covalent bond to ensure easy dissociation
- DThe proximal HisF8 aids linear configuration of the O2 molecule via a strong covalent bond to ensure easy dissociation
5Which of the following is INCORRECT
- AThe distal HisE7 prevents the oxidation of the haem Fe2+ to Fe3+
- BThe distal HisE7 prevents other molecules such as carbon monoxide from binding where oxygen should bind
- CThe distal HisE7 causes a conformational change to the subunit when oxygen binds as the Fe is pulled up into the plane of the haem
- DThe distal HisE7 ensures weakish binding of oxygen so that oxygen can be released into the tissues
6Which of the following is CORRECT
- ADuring carbon monoxide poisoning, the CO is in a linear configuration making it difficult to be released from the binding site
- BDuring carbon monoxide poisoning, the CO is in a bent configuration, but CO has 250x greater affinity for Hb over oxygen
- CDuring carbon monoxide poisoning, the CO is in a bent configuration making it easier to be released from the binding site
- DDuring carbon monoxide poisoning, the CO is in a linear configuration, and also has a 250x greater affinity for Hb over oxygen
7Which of the following is CORRECT
- AHaemoglobin displays a parabolic relationship between saturation and partial pressure of oxygen as it has co-operativity
- BMyoglobin displays a parabolic relationship between saturation and partial pressure of oxygen as it does not have co-operativity
- CMyoglobin displays a sigmoidal relationship between saturation and partial pressure of oxygen as it has co-operativity
- DMyoglobin displays a sigmoidal relationship between saturation and partial pressure of oxygen as it does not have co-operativity
8Which of the following is CORRECT
- AMyoglobin has a high O2 saturation at low partial pressure in the tissues
- BMyoglobin has a low O2 saturation at high partial pressure in the tissues
- CMyoglobin has a high O2 saturation at high partial pressure in the tissues
- DMyoglobin has a low O2 saturation at low partial pressure in the tissues
9Which of the following is CORRECT
- AHaemoglobin has a low O2 affinity in it's R state
- BHaemoglobin has a high O2 affinity in its R state
- CHaemoglobin has a high O2 affinity in its T state
- DHaemoglobin has the same affinity for O2 regardless of whether it is in its T state or R state
10Which of the following is CORRECT
- AAn allosteric regulator is a molecule that binds to a site on the enzyme which is NOT the active site
- BAn allosteric regulator is a molecule that acts as a competitive inhibitor to an enzyme
- CAn allosteric regulator is one which does not bind the the allosteric site on an enzyme
- DAn allosteric regulator changes the function of an enzyme by binding to its active site
11Which of the following are allosteric regulators in Haemoglobin
- ABPG
- BH+
- CCO2
- DO2
- EpH
- FCO
12When oxygen binds to the sixth co-ordination site on the [blank_start]Fe2+[blank_end], a conformational change occurs where the [blank_start]Fe2+[blank_end] is pulled [blank_start]up[blank_end] to be on the [blank_start]same[blank_end] plane as the haem. This is because the Fe2+ becomes [blank_start]smaller[blank_end] and can now fit. It pulls the [blank_start]proximal[blank_end] [blank_start]HisF8[blank_end] with it, which therefore c[blank_start]hanges[blank_end] the F helix, and all other helices attached to it in the [blank_start]subunit[blank_end].
- AFe2+
- BFe2+
- Cup
- Dsame
- Esmaller
- Fproximal
- GHisF8
- Hhanges
- Isubunit
13Co-operativity implies that once one oxygen has bound, it becomes much more [blank_start]easy[blank_end] to bind more. Haemoglobin follows the [blank_start]concerted[blank_end] model of co-operativity with elements of the [blank_start]sequential[blank_end] model. The sequential model is where d[blank_start]ifferent[blank_end] subunits can be in [blank_start]either[blank_end] the T or the R state at any one time. The concerted model is where a[blank_start]ll[blank_end] subunits are [blank_start]either[blank_end] in the T or the R state regardless of whether or not [blank_start]O2[blank_end] is bound. However once O2 has bound, it is [blank_start]more[blank_end] likely that they will all be in the [blank_start]R[blank_end] state.
- Aeasy
- Bconcerted
- Csequential
- Different
- Eeither
- Fll
- Geither
- HO2
- Imore
- JR
14BPG is the [blank_start]most[blank_end] effective [blank_start]allosteric[blank_end] regulator for haemoglobin produced when you [blank_start]exercise[blank_end]. It carries f[blank_start]ive[blank_end] [blank_start]negative[blank_end] charges that binds in the [blank_start]positively[blank_end] charged pocket created by H[blank_start]istidine[blank_end] and L[blank_start]ysine[blank_end] in the [blank_start]beta[blank_end] subunits. It favours the [blank_start]T[blank_end] state of haemoglobin, which means that more O2 is r[blank_start]eleased[blank_end] and less is r[blank_start]ebound[blank_end] to keep enough oxygen in the tissues. It shifts the sigmoidal curve to the [blank_start]right[blank_end].
- Amost
- Ballosteric
- Cexercise
- Dive
- Enegative
- Fpositively
- Gistidine
- Hysine
- Ibeta
- JT
- Keleased
- Lebound
- Mright
15CO2 is another [blank_start]allosteric[blank_end] regulator produced when you exercise, it shifts the b[blank_start]lood[blank_end] b[blank_start]uffer[blank_end] e[blank_start]quilibrium[blank_end] to favour [blank_start]H+[blank_end] production ([blank_start]H+[blank_end] is another allosteric regulator). This leads to a [blank_start]decrease[blank_end] in pH, which therefore favours the [blank_start]T[blank_end]-state and haemoglobin therefore has [blank_start]lower[blank_end] O2 affinity.
- Aallosteric
- Blood
- Cuffer
- Dquilibrium
- EH+
- FH+
- Gdecrease
- HT
- Ilower
16Which of the following are CORRECT
- AA decrease in BPG, increase in pH and decrease in H+ correlates to a left shift of the sigmoidal curve meaning that the R state is favoured and there is an increase in O2 affinity
- BA decrease in BPG, increase in pH and decrease in H+ correlates to a right shift of the sigmoidal curve meaning that the T state is favoured and there is an decrease in O2 affinity
- CAn increase in BPG, decrease in pH and increase in H+ correlates to a right shift of the sigmoidal curve meaning that the T state is favoured and there is an decrease in O2 affinity
- DAn increase in BPG, decrease in pH and increase in H+ correlates to a right shift of the sigmoidal curve meaning that the R state is favoured and there is an increase in O2 affinity
17Sickle cell anaemia occurs due changes in the s[blank_start]ixth[blank_end] amino acid on the [blank_start]beta[blank_end] sub-unit of haemoglobin. A p[blank_start]olar[blank_end], [blank_start]charged[blank_end] g[blank_start]lutamate[blank_end] is replaced with a [blank_start]non[blank_end]-[blank_start]polar[blank_end], [blank_start]charged[blank_end] v[blank_start]aline[blank_end]. This means that in the d[blank_start]eoxygenated[blank_end] state, h[blank_start]ydrophobic[blank_end] bulges and pockets form on the [blank_start]beta[blank_end] sub-unit, and haemoglobin molecules can [blank_start]bind[blank_end] to each other within the red blood cell, causing a distortion of its shape.
- Aixth
- Bbeta
- Colar
- Dcharged
- Elutamate
- Fnon
- Gpolar
- Hhyderophobic
- Ieoxygenated
- Jydrophobic
- Kbeta
- Lbind
- Maline
18Hb Boston occurs due to mutations in the [blank_start]alpha[blank_end] subunit. The [blank_start]Distal[blank_end] [blank_start]HisE7[blank_end] is replaced with a [blank_start]tyrosine[blank_end] amino acid, causing displacement of the [blank_start]proximal[blank_end] [blank_start]HisF8[blank_end]. This means that [blank_start]proximal[blank_end] [blank_start]HisF8[blank_end] becomes the 5th ligand , [blank_start]stabilising[blank_end] the haem ion in its r[blank_start]educed[blank_end], f[blank_start]erric[blank_end] state in the [blank_start]alpha[blank_end] sub-unit, which means that the [blank_start]alpha[blank_end] subunits can no longer bind oxygen. Displacement of [blank_start]HisE7[blank_end] also changes the [blank_start]plane[blank_end] of the haem so that [blank_start]beta[blank_end] haem groups can longer bind O2 either.
- Aalpha
- BDistal
- CHisE7
- Dtyrosine
- Eproximal
- FHisF8
- Gproximal
- HHisF8
- Ieduced
- Jerric
- Kstabilising
- Lalpha
- Malpha
- NHisE7
- Obeta
- Pplane
19In fetal haemoglobin, there are a few structural and chemical differences. The [blank_start]beta[blank_end] subunits are replaced with [blank_start]gamma[blank_end] subunits, this means that there is a [blank_start]lower[blank_end] affinity to BPG, therefore a [blank_start]high[blank_end] O2 affinity. This is due to the [blank_start]positively[blank_end] charged H[blank_start]istidine[blank_end] being replaced with a [blank_start]neutral[blank_end] S[blank_start]erine[blank_end], so there is [blank_start]less[blank_end] of an attraction between the subunit and allosteric regulator.
- Abeta
- Bgamma
- Clower
- Dhigh
- Epositively
- Fistidine
- Gneutral
- Herine
- Iless
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- Medicine (BIOC 192) Quiz on Lecture Tutorial 2 - Myoglobin and Haemoglobin, created by Eva Bonning on 12/09/2017.
- Author
- Eva Bonning
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- English
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