Download Q Globular proteins

Globular proteins
1) Iron in the center of the heme that bond to the four nitrogen’s of the porphyrin ring and two
additional bond with:
a. One coordinated to the histidine residue , the other position is free .
b. One coordinated to the histidine residue , the other position is to bind oxygen.
c. Two positions is coordinated to the side chain of a histidine residue.
d. Two position is available to bind oxygen.
2) Myoglobin structure is:
a. each α-helix terminated by proline.
b. eight stretches of α-helix.
c. stabilized by hydrogen bonds and ionic bonds.
d. all of these
3) Hemoglobin stabilized by:
a. hydrogen bonds.
b. ionic bonds.
c. hydrophobic interaction
d. all of these
4) The function of distal histidine (E7) is:
a. helps stabilize the binding of oxygen to the ferrous iron.
b. helps stabilize the heme group.
c. a. helps stabilize the binding of CO2to the ferrous iron.
d. no function
5) Myoglobin can transfer:
a. Four molecule of oxygen
b. Two molecule of oxygen
c. One molecule of oxygen
d. one atom of oxygen
5) Hemoglobin A, the major hemoglobin in adults, is composed of:
a. Two α chains and two β chains, held together by noncovalent interactions.
b. Two α chains and two β chains, held together by covalent interactions.
c. Two α chains and two β chains, held together by disulfide bond interactions.
d. Two α chains separated from another two β chains.
6) α and β-subunits within each dimer (αβ)1 and (αβ)2 are held together by:
a. ionic bond
b. hydrogen bond.
c. hydrophobic interactions
d. non of above
6) Taut (T) form is:
a. The deoxy form of hemoglobin.
b. two αβ dimers interact through high No. of ionic bonds and hydrogen bonds
c. low oxygen affinity form of hemoglobin.
d. all a,b and c.
7) Relax (R) form is:
a. The oxyhemogobin form.
b. high oxygen affinity form of hemoglobin.
c. rupture of some of the ionic bonds and hydrogen bonds between the αβ dimers
d. all a, b and c.
8) What is the different between T form and R form?
a. Oxygen binding to the R form, but T form is not.
b. Partial ruptures in ionic bonds and hydrogen bonds between the (αβ) dimers.
c. both a and b.
d. The T form is the high oxygen affinity form of hemoglobin.
9) Hemoglobin can bind with:
a. Four molecule of oxygen
b. Two molecule of oxygen
c. One molecule of oxygen
d. four atom of oxygen
10) Which of the following statements is true about Oxygen dissociation curve?
a. The myoglobin has a higher oxygen affinity at all pO2 values than does hemoglobin.
b. The myoglobin has a lower oxygen affinity at all pO2 values than does hemoglobin.
c. The myoglobin and hemoglobin has a equal oxygen affinity at all pO2 values.
11) Sigmoidal oxygen dissociation curve is a property of
a. Hemoglobin
b. Carboxyhaemoglobin
c. Myoglobin
d. Methaemoglobin
12) The oxygen dissociation curve for myoglobin has a
a. hyperbolic shape
b. sigmoidal shape
c. allosteric effect
d. hemoglobin
11) As hemoglobin binds oxygen molecules, its affinity for oxygen increases, driving the binding of
further oxygen molecules. Which term best describes this phenomenon?
a. Catalysis
b. Saturation
c. allosteric effect
d. isomerism
12) Which of the following statements about Bohr Effect is incorrect?
a. Shifting of oxyhemoglobin dissociation curve to the right
b. Shifting of oxyhemoglobin dissociation curve to the left
c. T(deoxy) form is stable
d. Increased pCO2 and decreased pO2
13) Mutations in two β-globin gene, at position six the glutamate converts to valine cause the:
a. Hb C disease
b. Hb S disease (sicke cell)
c. β- Thalassemias
d. α- Thalassemias
14) Mutations in two β-globin gene, at position six the glutamate converts to valine cause the:
a. Hb C disease
b. Hb S disease (sickle cell)
c. β- Thalassemias
d. α- Thalassemias
15) Which of the following statements about heterozygous is correct?
a. less susceptible to malaria because the RBCs has short life.
b. have one normal and one sickle cell gene in β-globin gene of hemoglobin.
c. do not show clinical symptoms and can have a normal life span.
d. all of these.
16) When the synthesis of β-globin chains in chromosome No 11 is complete absent that can be cause:
a. β-thalassemia minor
b. β-thalassemia major
c. Hemoglobin SC disease
d. α-Thalassemia
17) When the synthesis of α-globin chains in chromosome No 16 is decreased or absent that can be cause:
a. β-thalassemia minor
b. β-thalassemia major
c. Hemoglobin SC disease
d. α-thalassemia