Questions and Answers
What is the physiological significance of the Bohr effect on hemoglobin's affinity for oxygen?
How does carbon monoxide (CO) interact with hemoglobin compared to oxygen?
What role does 2,3-bisphosphoglycerate (BPG) play in hemoglobin's function?
How does the presence of the gamma subunit in fetal hemoglobin (HbF) affect its affinity for oxygen?
Signup and view all the answers
What is the relationship between hemoglobin and acid-base homeostasis?
Signup and view all the answers
What is the genetic basis of thalassemias?
Signup and view all the answers
What percentage of sequence homology exists between Mb and Hb?
Signup and view all the answers
Which of the following amino acids is conserved across species when comparing Mb and Hb?
Signup and view all the answers
What is the structural composition of myoglobin?
Signup and view all the answers
Which gene is expressed only at the embryonic stage in the alpha gene cluster?
Signup and view all the answers
Which of the following correctly describes the interaction of oxygen with hemoglobin?
Signup and view all the answers
What is the composition of fetal hemoglobin (HbF)?
Signup and view all the answers
Which of these statements about the α and β gene families is correct?
Signup and view all the answers
What distinguishes the structure of hemoglobin from myoglobin?
Signup and view all the answers
Which form of hemoglobin contains the δ gene?
Signup and view all the answers
Which chains are included in normal adult hemoglobin (HbA1)?
Signup and view all the answers
How many distinct α-helical regions are present in globin proteins like myoglobin and hemoglobin?
Signup and view all the answers
What characteristic distinguishes the β family of hemoglobin subunits?
Signup and view all the answers
How many conserved residues are there when comparing Mb and Hb across species?
Signup and view all the answers
What role do the histidine residues play in hemoglobin's structure?
Signup and view all the answers
What drives and stabilizes the structure of myoglobin?
Signup and view all the answers
Which of the following statements about hemoglobin is false?
Signup and view all the answers
What is the primary role of BPG in hemoglobin function?
Signup and view all the answers
How does the absence of BPG influence the oxygen saturation curve of hemoglobin?
Signup and view all the answers
Which amino acid residues does BPG interact with within the hemoglobin molecule?
Signup and view all the answers
What physiological adaptation occurs in response to high altitude concerning BPG?
Signup and view all the answers
What effect does BPG have on hemoglobin's affinity for oxygen?
Signup and view all the answers
What is the mechanism by which BPG affects oxygen binding cooperativity in hemoglobin?
Signup and view all the answers
What is the consequence of the reduced production of α globin chains in adults?
Signup and view all the answers
Which genotype corresponds to the asymptomatic (silent carrier) phenotype?
Signup and view all the answers
In which condition is HbH disease primarily characterized by?
Signup and view all the answers
What is the expected phenotype when all four α loci are affected?
Signup and view all the answers
Which of the following genotypes represents the α thalassemia Minor phenotype?
Signup and view all the answers
What is a characteristic feature of the α thalassemias when only one locus is affected?
Signup and view all the answers
Hb Bart's is primarily formed from which chains, and when is it most prevalent?
Signup and view all the answers
The severity of α thalassemias is correlated with what factor?
Signup and view all the answers
Study Notes
Physiological Significance of Protons, CO2, BPG, and HbF
- The Bohr Effect describes how protons (H+) and carbon dioxide (CO2) decrease hemoglobin's (Hb) affinity for oxygen (O2) by stabilizing the T (tense) state.
- Increased CO2 levels lead to more H+ ions, promoting oxygen release in tissues where it is most needed.
- BPG (2,3-bisphosphoglycerate) lowers O2 affinity by binding to hemoglobin, facilitating O2 release, especially under conditions of hypoxia or high altitude.
- Fetal hemoglobin (HbF) with γ-subunits has a higher affinity for O2 than adult Hb (α2β2), favoring oxygen transfer from maternal blood to fetus.
Carbon Monoxide (CO) Binding
- Carbon monoxide competes with oxygen for binding sites on hemoglobin due to its higher affinity for heme iron.
- The presence of distal histidine in hemoglobin reduces this affinity, making it less effective for CO binding compared to O2.
- CO binding inhibits oxygen release, leading to potential tissue hypoxia.
Hemoglobin and Acid-Base Homeostasis
- Hemoglobin acts as a buffer in the blood, binding excess H+ ions and CO2, which helps maintain pH levels in the body.
- The interaction between deoxygenated hemoglobin and protons promotes the release of O2, supporting cellular respiration and acid-base balance.
Molecular Genetic Basis of Thalassemias
- Thalassemias are genetic disorders caused by mutations in globin gene clusters, leading to reduced production of either α or β globin chains.
- The severity of α-thalassemia correlates with the number of affected α globin loci; more loci affected results in more severe disease manifestations.
- Genotype-phenotype relationships show that the degree of symptomatology differs greatly with variations in affected loci.
- Excess β chains in α-thalassemia result in the formation of unstable tetramers (HbH), leading to altered oxygen dissociation properties.
- In β-thalassemia, mutations reduce β chain production leading to α chain accumulation, causing ineffective erythropoiesis and anemia.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the physiological significance of protons, carbon dioxide, and bisphosphoglycerate in hemoglobin function. Understand the Bohr Effect, the intricacies of oxygen release under different conditions, and the impact of carbon monoxide binding on hemoglobin. This quiz delves into the factors that influence oxygen affinity and transport in the body.