hemoglobin question

[allstardentist]

O2 affinity of hemoglobin

A. is unaffected under all physiologic circumstances.
B. increases when the blood pH is low.
C. decreases when exchanging for gases at the aveoli.
D. is not regulated by subunit cooperativity.
E. decreases in the presence of carbonic acids known as the Bohr shift effect.

The answer is E. Why is it not B?

According to a source, " the lower pH will cause Hb to deliver more oxygen".

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[fancymylotus]

O2 affinity of hemoglobin

A. is unaffected under all physiologic circumstances.
B. increases when the blood pH is low.
C. decreases when exchanging for gases at the aveoli.
D. is not regulated by subunit cooperativity.
E. decreases in the presence of carbonic acids known as the Bohr shift effect.

The answer is E. Why is it not B?

According to a source, " the lower pH will cause Hb to deliver more oxygen".

the o2 dissociation curve shifts when ph drops or pp of co2 rises

 

[fancymylotus]

 

[allstardentist]

so shouldnt it be B? The pp of O2 increases after the shift.

 

[allstardentist]

oh ok. got it.

 

[fancymylotus]

so shouldnt it be B? The pp of O2 increases after the shift.

as far as i know,bohr shift is caused by ph dropping or by the addition or co2 or other co2ish acid which makes more o2 get released by increasing the pp of 02

 

[tinman831]

Low blood pH = high carbon dioxide level. You don't want the hemoglobin to hold onto the oxygen so tightly. You want the hemoglobin to deliver the oxygen to the tissues as fast as possible.

 

[JohnDoeDDS]

yep what tinman said. This guy knows his stuff!

 

[alexandersydney]

wait-if blood ph is low, which means hemoglobin affininty for 02 is low won't it make it harder to uptake 02 by breathing?

 

[deleted100801]

think about it this way. tissues that are actively metabolizing are going to be dishing out massive amounts of CO2 and this will create an acidic microenvironment. As a result you will want more O2 delivery to these tissues in particular, and thanks to the Bohr effect, this will occur. Blood pH varies from tissue to tissue.

 

[INFNITE]

when you have low pH, it means you have high CO2. You want to have the hemoglobin release oxygen therefore you want to decrease the binding affinity of Oxygen (shift to right). You'll learn all about it in biochemistry.

 

[cocokeala]

high CO2. low PH, hemoglobin in T state--> lower affinity for O2.

 

[gildas]

O2 affinity of hemoglobin

A. is unaffected under all physiologic circumstances.
B. increases when the blood pH is low.
C. decreases when exchanging for gases at the aveoli.
D. is not regulated by subunit cooperativity.
E. decreases in the presence of carbonic acids known as the Bohr shift effect.

The answer is E. Why is it not B?

According to a source, " the lower pH will cause Hb to deliver more oxygen".

Simple answer: When the pH is Low, you have higher concentration of H in your body which correlate to a higher concentration of CO2. A higher CO2 pressure will decrease the affinity of hemoglobin because it will try to compensate by making more O2 available to the tissue.
I hope this helps.