Flashcards in 9. Hemoglobin Deck (20):
Hemoglobin is composed of
4 polypeptide subunits
2α and 2β
1 heme in every polypetptide
hemoglobin (hb) is exists in how many and which forms
T form and R form
hemoglobin (hb) - T form properties
Taut form deoxygenated low affinity for O2
hemoglonim ( hb ) - R form properties
high affinity for O2 ( x300)
hb - properties
1. positive cooperativity
2. negative allostery
hemoglobin (hb) - positive cooperativity
tetrameric Hb molecule can bin 4 O2 molecules and has higher affinity for each subsequent O2 molecule bound
substance that favor taut form over relaxed dorm ( shift curve to right)
INCREASED CL-, H+, CO2, 2,3 BPG, temperature
fetal hemoglobin subunits
2α and 2γ
fetal hemoglobin vs adult ( about funtion
lower affinity for 2.3 - BPG than adult hemoglobin and thus higher affinity for O2
hemoglobin also act as
a buffer for H+ ions
buffer for H+ ions
How many polypeptide subunits make up hemoglobin?
What are the two conformational forms of hemoglobin?
Relaxed (oxygenated) and taut (deoxygenated)
• Of the two forms of hemoglobin, the taut (T) form has ____ (high/low) affinity for oxygen. The relaxed (R) form has ____ (high/low) affinity.
Low; high (300 times more affinity in R form) (Taut in Tissues, Relaxed in Respiratory tract)
Does hemoglobin have positive or negative cooperativity with respect to oxygen binding and affinity?
Does hemoglobin have positive or negative allostery with respect to oxygen binding and affinity?
An increase in which five factors will favor the taut form of hemoglobin over the relaxed form and will decrease affinity for oxygen?
Chloride (Cl-), protons (H+), carbon dioxide, 2,3-bisphosphoglycerate, and temperature
A patient is exercising in the freezing cold. He is otherwise healthy. Is his hemoglobin more likely to be taut or relaxed?
Taut, as exercise (generating CO2) favors the taut form (the outside temperatures are meaningless, as body temperature is what matters)
Fetal hemoglobin has ____ (higher/lower) affinity for 2,3-BPG than does adult hemoglobin, causing ____ a (higher/lower) affinity for oxygen.