12 Questions
What is the quaternary structure of hemoglobin?
Consists of 4 polypeptide chains and 4 heme groups
Which type of protein is hemoglobin?
Allosteric protein
What conformation of hemoglobin allows oxygen binding?
R state
How are the subunits of hemoglobin arranged?
In symmetric pairs without covalent bonds
What is the name of the state in which the four subunits of hemoglobin are unable to attach oxygen?
T state
What is the name of the state in which the four subunits of hemoglobin can carry attached oxygen?
R state
What is the process called when hemoglobin transitions from T state to R state?
T to R transition
What happens when hemoglobin is in T state in the lungs area?
One oxygen molecule contacts one of the four subunits, inducing a conformational change
What effect do increased concentrations of protons and CO2 have on the affinity of hemoglobin for oxygen?
It reduces the affinity of hemoglobin for oxygen
What is the role of 2,3-biphosphoglycerate (BPG) in relation to hemoglobin's affinity for oxygen?
It decreases the affinity of hemoglobin for oxygen
What is the name of the process that includes the digestion of molecules by cells in order to obtain energy?
Cellular respiration
What are the end products of cellular respiration from tissues that affect the affinity of hemoglobin for oxygen?
Protons and CO2
Study Notes
Hemoglobin Structure and Function
- Hemoglobin is a tetrameric protein, consisting of four subunits (α, β, α, β)
- The quaternary structure of hemoglobin is a tetrahedral arrangement of these subunits
- Hemoglobin is a globular protein
Oxygen Binding
- The R-state conformation of hemoglobin allows oxygen binding
- In this state, the subunits are arranged in a relaxed, open structure
- The T-state conformation, also known as the deoxy state, is when the four subunits are unable to attach oxygen
- The R-state conformation, also known as the oxy state, is when the four subunits can carry attached oxygen
Transition between States
- The process of transitioning from T-state to R-state is called cooperativity
- When hemoglobin is in T-state in the lungs area, it is able to bind to oxygen more efficiently
Factors Affecting Oxygen Affinity
- Increased concentrations of protons and CO2 reduce the affinity of hemoglobin for oxygen
- 2,3-biphosphoglycerate (BPG) decreases the affinity of hemoglobin for oxygen
- This is important for releasing oxygen to tissues
Cellular Respiration
- Cellular respiration is the process by which cells digest molecules to obtain energy
- The end products of cellular respiration from tissues that affect the affinity of hemoglobin for oxygen are CO2 and protons
Test your knowledge of hemoglobin with this quiz. Explore the quaternary structure, polypeptide chains, and heme groups of this crucial protein.
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