BIO 1500 EXAM #5 QUESTIONS AND
ANSWERS
explain the basic properties required of an O2 transport molecule - ANSWER-1.
effectively bind o2 in the lung
--> high affinity
2. effectively release o2 in the body
--> low affinity
interpret the O2-Hb-dissociation curve, and relate its shape to the structure of Hb -
ANSWER-right shift = low affinity Hb
left shift = high affinity Hb
high affinity - ANSWER-grabs o2 easily & holds onto it tightly
low affinity - ANSWER-grabs o2 less readily & lets it go easily
connect molecular changes during O2binding to cooperative O2binding properties of
Hb - ANSWER-Hb molecule changes shape in a way that makes it easier for more
o2 to bind to it
-when o2 attaches to Hb, it makes it easier for more o2 to bind to the Hb
-No o2= bent/tense state
-2/ o2= flat/relaxed state
relate the O2-Hb dissociation curve to the partial O2pressure in lung and body and
explain the advantage of its sigmoidal shape. - ANSWER--in lung: close to 100% for
wide range pO2
-in body: steep part of curve
BIG CHANGE WHEN pO2 DROPS
At normal body pO2, Hb keeps 70-80% of o2
--> only releases 20-30% o2
Sigmoidal shape comes from cooperative o2 binding
Explain how the O2 affinity of Hb decreases in the body, incl. which factors
contribute to this decrease and how this facilitates the release of O2in the body -
ANSWER-pCO2 is increased, =right shift = low affinity
CO2 dissolved in H2o forms
H2CO3 --> H+ + HCO3 --> decrease in pH
Higher temperature (work, cooling in lungs)
ANSWERS
explain the basic properties required of an O2 transport molecule - ANSWER-1.
effectively bind o2 in the lung
--> high affinity
2. effectively release o2 in the body
--> low affinity
interpret the O2-Hb-dissociation curve, and relate its shape to the structure of Hb -
ANSWER-right shift = low affinity Hb
left shift = high affinity Hb
high affinity - ANSWER-grabs o2 easily & holds onto it tightly
low affinity - ANSWER-grabs o2 less readily & lets it go easily
connect molecular changes during O2binding to cooperative O2binding properties of
Hb - ANSWER-Hb molecule changes shape in a way that makes it easier for more
o2 to bind to it
-when o2 attaches to Hb, it makes it easier for more o2 to bind to the Hb
-No o2= bent/tense state
-2/ o2= flat/relaxed state
relate the O2-Hb dissociation curve to the partial O2pressure in lung and body and
explain the advantage of its sigmoidal shape. - ANSWER--in lung: close to 100% for
wide range pO2
-in body: steep part of curve
BIG CHANGE WHEN pO2 DROPS
At normal body pO2, Hb keeps 70-80% of o2
--> only releases 20-30% o2
Sigmoidal shape comes from cooperative o2 binding
Explain how the O2 affinity of Hb decreases in the body, incl. which factors
contribute to this decrease and how this facilitates the release of O2in the body -
ANSWER-pCO2 is increased, =right shift = low affinity
CO2 dissolved in H2o forms
H2CO3 --> H+ + HCO3 --> decrease in pH
Higher temperature (work, cooling in lungs)
