FFLD 7 Flashcards
Haemoglobin is:
A. An iron (Fe) transporter and storage molecule
B. An on-site oxygen storage molecule for muscle tissues
C. An oxygen transporter to peripheral tissues
D. A myoglobin globin store
C
Which one of the following accurately describes the structure of haemoglobin (Hb)?
A. The secondary structure of Hb is mainly beta-sheet.
B. Hb is a tetramer with two different types of subunits
C. Each globin protein in Hb has four haem rings.
D. Normal adult haemoglobin has eight alpha-globins.
B
Select the incorrect statement about myoglobin and haemoglobin
A. They have their haem Fe atom held in place in the globin via four nitrogen (N) atoms and an N atom from the side chain of His F8 (aka proximal His).
B. They both have their 6th coordination site occupied by oxygen at high oxygen pressures pressures.
C. Upon oxygen binding, the F helix moves quite significantly to change the shape of the globin unit while the other alpha helices remain in their original position.
D. They have His E7 sterically pushing on bound oxygen to prevent it from binding too tightly to the haem Fe to ensure the oxygen can be released.
C
Oxygen binding to haemoglobin can easily be evaluated by:
A. Spectroscopy which measures how much light is being absorbed by a sample in solution
B. Spectroscopy which calculates the amount of oxygen bound to a known haemoglobin concentration.
C. X-ray crystollagraphy which allows the determination of the protein structure in a solution and any molecules bound to it.
D. X-ray crystollagraphy which allows the determination of the number of oxygen molecules bound to a set number of haemoglobin proteins.
A
At the kinds of oxygen pressures (concentration) found in the body, myoglobin has a higher affinity for oxygen than haemoglobin. True or false?
True
Which one of the following statements about haem groups in haemoglobin is incorrect?
A. Haem groups have a central Fe atom that binds oxygen.
B. Haem groups form a bond to globin proteins via HisF8.
C. Haem Fe must be in the 2+ oxidation state for normal function.
D. Haem groups are on the surface of the globin protein, exposed to water.
C
