Oxygen delivery!
You're so tense. You need to relax!
Shift change!
100

Binding of one O2 increases Hb's affinity for subsequent O2 molecules through this phenomenon.

What is positive cooperativity?

100

O2 preferentially binds to this hemoglobin confirmation.

What is the relaxed state?



100

What is p50, and what is the relationship between p50 and affinity? 

What is: P50 indicates the concentration at which half of Hemoglobin is saturated with O2


P50 and affinity are inversely related

200

What are the components of Hemoglobin, and how many oxygen molecules can one Hg carry? 

What is two alpha two beta subunits, and 4 oxygen molecules. 

200

The first O2 molecule is harder to bind than the fourth because initial O2 binding disrupts interactions stabilizing this Hb conformation.

What is the tense state?

200

What 4 things cause an increase in P50, and are they short-term or long-term?

What is

Short-term: [H+], [CO2], and Co

Long-term: 2,3-BPG

300

The sequential binding nature of oxygen serves to remedy which physiological problem?

What is: it allows you to deliver oxygen over a very narrow range of partial pressure. 

300

How do Fe3+ and CO affect hemoglobin, and why is this physiologically relevant?

What is: they essentially lock hemoglobin molecules in the relaxed state (decreasing P50), making them unable to release oxygen at the tissues?

300

Explain how high sea levels lead to shift change over time and why (physiologically) does this occur? 

Bonus: how long does this take?

What is: 

Lower O2 partial pressure = decreased ETC ability = increased AMP => increased 2,3-BPG => stabilizes the deoxy-Hb (tense) state = p50 moves to the right. 

What is This takes hours to days.

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