3.2 Quiz 1

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Questions and Answers

Which of the following is true about Myoglobin?

It has a hyperbolic dissociation curve with a P50 close to that of HbA. (correct)

It is structurally different from any subunit of Hemoglobin.

It binds with multiple oxygen molecules simultaneously.

It is a multi-polypeptide heme protein.

What happens to the oxygen-hemoglobin dissociation curve with a decrease in 2,3-DPG?

Becomes steeper but does not shift.

Shifts to the right and increases available O2.

Remains unchanged as 2,3-DPG does not affect the curve.

Shifts to the left and reduces available O2. (correct)

What effect does Carbon Monoxide have on the oxygen-hemoglobin dissociation curve?

Shifts it to the left in the shallow portion. (correct)

Does not affect the curve shape but decreases the affinity for O2.

Shifts it to the right, increasing the upper flat portion.

Causes no shift but increases the affinity for CO2.

How do most hemoglobinopathies affect the oxygen-hemoglobin dissociation curve?

They shift the curve left and reduce available O2. Signup and view all the answers

In what way does a decrease in temperature affect the oxygen-hemoglobin dissociation curve?

Shifts it to the left and increases affinity for O2. Signup and view all the answers

What is a factor that causes a right shift in the oxygen-hemoglobin dissociation curve related to metabolism or acidosis?

Increased CO2 from metabolism Signup and view all the answers

Which molecule is produced during RBC glycolysis and helps maintain the oxygen-hemoglobin dissociation curve slightly right at all times?

2,3 DPG Signup and view all the answers

What is a factor that causes a left shift in the oxygen-hemoglobin dissociation curve?

Decreased pH Signup and view all the answers

Which condition is associated with an increase in 2,3 DPG, facilitating offloading of oxygen?

Hypoxia Signup and view all the answers

What is a factor that causes a right shift in the oxygen-hemoglobin dissociation curve specifically related to acidosis?

Increased CO2 Signup and view all the answers

What is the term used to describe the phenomenon where oxygen binding increases the affinity of hemoglobin for more oxygen?

Bohr effect Signup and view all the answers

Which compound is responsible for promoting the release of oxygen from hemoglobin in tissues by shifting the oxygen-hemoglobin dissociation curve to the right?

2,3 diphosphoglycerate (2,3 DPG) Signup and view all the answers

In which form does hemoglobin exist when it is not combined with oxygen?

Methemoglobin Signup and view all the answers

What is the term used to describe a left shift in the oxygen-hemoglobin dissociation curve that results in increased hemoglobin's affinity for oxygen?

Allosteric effect Signup and view all the answers

Which factor can significantly affect the oxygen-hemoglobin dissociation curve by altering hemoglobin's affinity for oxygen?

Body temperature Signup and view all the answers

Which of the following contributes to the left shift in the oxygen-hemoglobin dissociation curve?

Decreased pH Signup and view all the answers

In a scenario with increased 2,3 DPG levels, how would this affect the oxygen-hemoglobin dissociation curve?

Shift to the right Signup and view all the answers

Which of the following hemoglobinopathies is associated with a defect in the beta-globin chain?

Sickle cell anemia Signup and view all the answers

What is the primary function of 2,3 DPG (2,3 diphosphoglycerate) in relation to oxygen transport?

Promotes the release of oxygen from hemoglobin Signup and view all the answers

Which factor shifts the oxygen-hemoglobin dissociation curve to the right?

Increased 2,3 DPG levels Signup and view all the answers

What is the significance of the steep portion of the oxyhemoglobin-dissociation curve?

Indicates a relatively small drop in PaO2 yields a large amount of O2 being unloaded Signup and view all the answers

What is the main factor responsible for shifting the oxyhemoglobin dissociation curve to the right?

Increased 2,3 DPG levels Signup and view all the answers

Which condition is associated with a left shift in the oxygen-hemoglobin dissociation curve?

Increased pH Signup and view all the answers

How does a decrease in pH affect the oxyhemoglobin dissociation curve?

Causes a right shift in the curve Signup and view all the answers

Which factor does NOT affect the oxygen-hemoglobin dissociation curve?

Partial pressure of oxygen (PaO2) Signup and view all the answers

What is the main function of carbonic anhydrase reaction in the context of hemoglobin and oxygen transport?

Generates H+ and HCO3- to facilitate the release of O2 from hemoglobin Signup and view all the answers

In which direction does the oxygen dissociation curve shift in response to the Bohr Effect?

To the right Signup and view all the answers

How does the chloride shift (Hamburger shift) impact the osmotic balance of erythrocytes?

Increases RBC volume relative to plasma volume Signup and view all the answers

What happens to the oxyhemoglobin dissociation curve during a left shift?

Shifts to the left Signup and view all the answers

Which factor contributes most significantly to the right shift in the oxygen-hemoglobin dissociation curve?

Increased 2,3-diphosphoglycerate (2,3 DPG) levels Signup and view all the answers

Which molecule is primarily responsible for shifting the oxyhemoglobin dissociation curve to the right?

2,3 DPG Signup and view all the answers

In which condition would you expect a right shift in the oxygen-hemoglobin dissociation curve?

Decreased 2,3 DPG levels Signup and view all the answers

What is the primary effect of the Bohr effect at the tissue level?

Decrease in pH causing increased oxygen release Signup and view all the answers

Which of the following conditions is most likely to result in a left shift in the oxygen-hemoglobin dissociation curve?

Anemia Signup and view all the answers

Which of the following is a common feature of both the Haldane effect and the Bohr effect?

Decreased affinity for CO2 in the presence of high O2 levels Signup and view all the answers

What is the primary function of 2,3 DPG in the context of oxygen transport?

Shift oxyhemoglobin dissociation curve to the right Signup and view all the answers

Which condition is most likely to cause a right shift in the oxygen-hemoglobin dissociation curve?

Elevated 2,3 DPG levels Signup and view all the answers

What happens to the oxygen-hemoglobin dissociation curve in a patient with carbon monoxide poisoning?

Shifts to the left Signup and view all the answers

Which factor contributes to a left shift in the oxygen-hemoglobin dissociation curve?

Decreased concentration of 2,3 DPG Signup and view all the answers

What impact does an increase in pH have on the oxygen-hemoglobin dissociation curve?

Left shift Signup and view all the answers

Study Notes

Hemoglobin and Oxygen Transport

Hemoglobin (Hb) is a single-polypeptide heme protein that stores O2 in red blood cells.
Hb combines with O2 in the lungs and releases it in the tissues.
The oxygen dissociation curve shows the relationship between PO2 and the percentage of oxygen combined with Hb.

Factors Affecting Oxygen Binding to Hemoglobin

Temperature: increases in temperature shift the curve to the right, decreasing Hb's affinity for O2.
2,3 Diphosphoglycerate (2,3 DPG): increases in 2,3 DPG shift the curve to the right, decreasing Hb's affinity for O2.
pH: decreases in pH (acidosis) shift the curve to the right, decreasing Hb's affinity for O2.
Carbon Monoxide (CO): binds to Hb at the same ferrous site as O2, shifting the curve to the left and increasing Hb's affinity for O2.

Hemoglobinopathies

Most hemoglobinopathies shift the oxygen dissociation curve to the left, increasing Hb's affinity for O2.
Examples: sickle cell anemia, thalassemia.

Myoglobin

Myoglobin is a single-polypeptide heme protein that stores O2 in muscle cells.
Myoglobin has a hyperbolic dissociation curve, differing from Hb's sigmoidal curve.
Myoglobin has a higher affinity for O2 than Hb.

Oxygen Content of Blood

Oxygen content of blood (CaO2) is the sum of O2 dissolved in plasma and O2 combined with Hb.
CaO2 is calculated using the equation: CaO2 = (1.34 x Hb x SaO2) + (PaO2 x 0.003).

Oxyhemoglobin Dissociation Curve

The oxyhemoglobin dissociation curve shows the relationship between PO2 and the percentage of oxygen combined with Hb.
The curve has a sigmoidal shape, with a steep portion representing O2 unloading in tissues.
The curve shifts to the right with decreases in pH, increases in temperature, and increases in 2,3 DPG.

Shifting of the Oxyhemoglobin Dissociation Curve

Right shift: decreased Hb affinity for O2, facilitating O2 release in tissues.
Left shift: increased Hb affinity for O2, reducing O2 release in tissues.
Factors causing a right shift: increased CO2, decreased pH, increased temperature, and increased 2,3 DPG.
Factors causing a left shift: decreased CO2, increased pH, decreased temperature, and decreased 2,3 DPG.

Chloride Shift (Hamburger Shift)

The uptake of chloride in exchange for HCO3- in erythrocytes.
Occurs in the tissues, facilitating CO2 transport.

Carbonic Anhydrase Reaction

Reverses in the lungs, increasing pH and shifting the oxyhemoglobin dissociation curve to the left.
Facilitates CO2 transport and O2 release in the lungs.

Haldane and Bohr Effects

Haldane effect: the amount of CO2 transported is affected by the PO2.
Bohr effect: the affinity of Hb for O2 is affected by the pH.
Both effects work together to facilitate O2 release in tissues and CO2 transport.

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Description

Test your knowledge on how the carbonic anhydrase reaction generates H+ and HCO3- in red blood cells, and how deoxyhemoglobin accepts H+ ions to facilitate O2 release. Explore concepts like the Bohr Effect and Chloride Shift in this quiz.