Questions 33-34 The following questions refer to this graph...

Questions $33-34$ The following questions refer to this graph that shows the rate at which relative amounts of oxygen bound to hemoglobin change as the partial pressure of oxygen changes. Based on this graph, which of the following statements is true? (A) At oxygen concentration 40 $\mathrm{mm}$ Hg, hemoglobin $\mathrm{A}$ is 40$\%$ saturated with oxygen, while hemoglobin $\mathrm{B}$ is at 20$\%$ (B) At oxygen concentration 60 $\mathrm{mm}$ Hg, hemoglobin $\mathrm{B}$ is 100$\%$ saturated with oxygen. (C) Hemoglobin A becomes 100$\%$ saturated with oxygen at 60 $\mathrm{mm} \mathrm{Hg} .$ (D) Hemoglobins A and B become saturated with oxygen at the same concentration of $\mathrm{O}_{2}$ . (E) Neither hemoglobin A nor hemogin $\mathrm{B}$ ever becomes 100$\%$ saturated with oxygen.

Questions $33-34$ The following questions refer to this graph that shows the rate at which relative amounts of oxygen bound to hemoglobin change as the partial pressure of oxygen changes.
Based on this graph, which of the following statements is true?
(A) At oxygen concentration 40 $\mathrm{mm}$ Hg, hemoglobin $\mathrm{A}$ is 40$\%$ saturated with oxygen, while hemoglobin $\mathrm{B}$ is at 20$\%$
(B) At oxygen concentration 60 $\mathrm{mm}$ Hg, hemoglobin $\mathrm{B}$ is 100$\%$ saturated with oxygen.
(C) Hemoglobin A becomes 100$\%$ saturated with oxygen at 60 $\mathrm{mm} \mathrm{Hg} .$
(D) Hemoglobins A and B become saturated with oxygen at the same concentration of $\mathrm{O}_{2}$ .
(E) Neither hemoglobin A nor hemogin $\mathrm{B}$ ever becomes 100$\%$ saturated with oxygen.

Key Concepts

Oxygen-Hemoglobin Dissociation Curve

This is a graphical representation showing the relationship between the partial pressure of oxygen and the degree of hemoglobin saturation. Its sigmoidal shape is a result of the cooperative binding of oxygen molecules to hemoglobin, making it a key concept in understanding oxygen transport in the blood.

Partial Pressure

Partial pressure refers to the pressure that oxygen exerts in a mixture of gases. It is a crucial factor in the binding of oxygen to hemoglobin, as changes in the partial pressure directly affect how much oxygen hemoglobin can carry, which is essential for gas exchange in the body.

Hemoglobin Saturation

Hemoglobin saturation is the percentage of hemoglobin binding sites occupied by oxygen at any given partial pressure. This concept is critical because it reflects how effectively the blood can transport oxygen to tissues and is directly represented by data on oxygen-hemoglobin dissociation curves.

Cooperative Binding

Cooperative binding describes the process by which the binding of one oxygen molecule to hemoglobin increases the affinity for additional oxygen molecules to bind. This phenomenon results in the sigmoidal shape of the oxygen-hemoglobin dissociation curve and is central to understanding how oxygen uptake and release are regulated in the blood.

Transcript

00:01 For this question, we are asked to find which of five answers is correct based on a graph showing the different abilities of hemoglobin a and hemoglobin b to bind to oxygen.

00:10 On our x -axis, we have the concentration of oxygen, and on our y -axis, we have the percent of oxygen saturation, meaning the percent that is bound.

00:19 In order to figure out this problem, we need to organize our data.

00:24 One way to do so is with charts like this.

00:28 Looking at the answers that are provided for us to choose from, we see that there are three different numbers that they are interested in.

00:36 So those are the only thing we need to focus.

00:39 The first two are the 40 and 60 millimeters of mercury for both hemoglobin a and b.

00:45 Those are the concentrations of oxygens, and we need to find what percentage of saturation.

00:52 The last number is 100 % oxygen saturation for both hemoglobin a and b.

00:57 We need to find the opposite.

00:58 What concentration does each hemoglobin reach that 100 % saturation? first off, we notice by reading the graph that at 40 millimeters mercury for hemoglobin a, which is that first left side curve, we have a oxygen saturation percentage of 40%.

01:21 For 60mm mercury concentration of oxygen, for hemoglobin a, we have 60%.

01:31 Now, for hemoglobin b, for each of those concentrations, 40 and 60%.

01:37 Based off of reading the graph, we'll see that at the lower concentration, it only has 20 % saturation.

01:46 And at the higher, it has 40 % saturation...

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