Biochem Unit 2 Exam Questions and Answers With complete
solution–Expert Verified
myglobin (Mb): stores oxygen in muscle cells
hemoglobin (Hb): Oxygen carrying pigment in red blood cells; carries from lungs to tissues and then returns
carbon dioxide to lungs
structure of myoglobin: -single polypeptide chain with 153 amino acids
-8 alpha helix
-globular protein
contains one heme group in hydrophobic pocket
structure of hemoglobin: -four polypeptide chains ( 2 alpha chains, 2 beta chains)
-protomers (identical subunits)
contains 4 heme groups
bind up to 4 heme groups
1/9
,binding is cooperative
cooperative binding: when O2 is bound it becomes easier for the next to bind
heme group: - cofactor helping protein function
iron atom and porphyrin ring
4 pyrrole aromatic rings (flat and planar)
what does Fe(2) bind to: nitrogen groups, O2, histidine group
can also bind to CO, NO, H2S and can cause carbon monoxide poisoning due to higher aflnity
oxygenated state: scarlet, filled with oxygen from lungs, R-state (relaxed), heme groups closer together
deoxygenated state: dark purple, most of its oxygen removed and returning to lungs, T state (tensed)
oxidation of Fe(2): when heme group is bound to O2, Fe (2) is oxidized to Fe(3)
what isomer of Fe does O2 bind to: 2
2/9
, how does hemoglobin change from T state to R state: -heme bends
becomes planar
-pulls His F8 down 0.6A
moves helix F 1A
a1b1 interactions in hemoglobin conformational change: deoxy: histidine residue on
b chain fits between proline and threonine on alpha chain
oxy: his residue between two Thr residues
3/9
solution–Expert Verified
myglobin (Mb): stores oxygen in muscle cells
hemoglobin (Hb): Oxygen carrying pigment in red blood cells; carries from lungs to tissues and then returns
carbon dioxide to lungs
structure of myoglobin: -single polypeptide chain with 153 amino acids
-8 alpha helix
-globular protein
contains one heme group in hydrophobic pocket
structure of hemoglobin: -four polypeptide chains ( 2 alpha chains, 2 beta chains)
-protomers (identical subunits)
contains 4 heme groups
bind up to 4 heme groups
1/9
,binding is cooperative
cooperative binding: when O2 is bound it becomes easier for the next to bind
heme group: - cofactor helping protein function
iron atom and porphyrin ring
4 pyrrole aromatic rings (flat and planar)
what does Fe(2) bind to: nitrogen groups, O2, histidine group
can also bind to CO, NO, H2S and can cause carbon monoxide poisoning due to higher aflnity
oxygenated state: scarlet, filled with oxygen from lungs, R-state (relaxed), heme groups closer together
deoxygenated state: dark purple, most of its oxygen removed and returning to lungs, T state (tensed)
oxidation of Fe(2): when heme group is bound to O2, Fe (2) is oxidized to Fe(3)
what isomer of Fe does O2 bind to: 2
2/9
, how does hemoglobin change from T state to R state: -heme bends
becomes planar
-pulls His F8 down 0.6A
moves helix F 1A
a1b1 interactions in hemoglobin conformational change: deoxy: histidine residue on
b chain fits between proline and threonine on alpha chain
oxy: his residue between two Thr residues
3/9
