$3.(4$ pts total$)$ Using the figure below of O$2$ binding to myoglobin and hemoglobin $($ignore the line marked as T$),$ answer the following questions.

myoglobin

$($a$)(0\mathrm{.}5$ pts$)$ Estimate the P$50$ for myoglobin and hemoglobin from the plot. Show how this estimation is determined from the binding curve above. Note: Although you may be able to find these values in the textbook, you must show how these values are obtained from the plot to receive full credit.

$($b$)(1$ pt$)$ Using YO$2=$ PO$2/($P$50+$ PO$2)$ and the value of P$50$ from your answer in part $($a$)$ calculate the fraction of O$2$ bound for myoglobin at $1$ torr.

Assignment A$02$ BCH $351$

$($c$)(0\mathrm{.}5$ pts$)$ Using the binding curve above, show how you can estimate what fraction of hemoglobin is bound near tissues at a pO$2$ of $35$ torr and provide this value.

$($d$)(1$ pt$)$ If the pH were lowered from pH $7\mathrm{.}5$ to pH $7\mathrm{.}0,$ will the amount of O$2$ bound to hemoglobin at $35$ torr increase or decrease? Explain why this is so based on how this change in pH alters the structure of hemoglobin.

$($e$)(1$ pt$)$ If $2,3-$bisphosphoglycerate $(2,3-$BPG$)$ were added to a solution containing hemoglobin at pH $7\mathrm{.}5,$ will the amount of O$2$ bound to hemoglobin at $35$ torr increase or decrease? Explain why this is so based on how the presence of $2,3-$BPG alters the structure of hemoglobin.