B3

• What is the main protein involved in the transport of respiratory gases?

  Hemoglobin
• How many oxygen molecules can hemoglobin transport?

  Four oxygen molecules
• What are the structural components of hemoglobin?

  It consists of four polypeptides and four heme groups
• What happens when an oxygen molecule binds to a heme group in hemoglobin?

  It causes a conformational change in the hemoglobin molecule
• What effect does the binding of oxygen have on hemoglobin's affinity for oxygen?

  It increases hemoglobin's affinity for oxygen
• What is the significance of the oxygen dissociation curve?

  It illustrates how hemoglobin's affinity for oxygen changes with partial pressure
• What does the term "partial pressure" refer to?

  The pressure exerted by one gas in a mixture of gases
• How does low partial pressure of oxygen affect hemoglobin's affinity for oxygen?

  It results in a low affinity for oxygen
• What shape does the oxygen dissociation curve for adult hemoglobin take?

  It is sigmoidal in shape
• Why does fetal hemoglobin have a higher affinity for oxygen than adult hemoglobin?

  It allows the fetus to extract oxygen from the mother's blood
• What happens to the oxygen dissociation curve for fetal hemoglobin compared to adult hemoglobin?

  It shifts to the left
• How does increased carbon dioxide affect hemoglobin's affinity for oxygen?

  It decreases hemoglobin's affinity for oxygen
• What is the Bohr shift?

  It is the rightward shift of the oxygen dissociation curve due to increased carbon dioxide
• What is the effect of high carbon dioxide content on hemoglobin's oxygen saturation?

  It results in lower oxygen saturation at the same partial pressure
• What are the key features of the oxygen dissociation curve for adult hemoglobin?

  • Sigmoidal shape
  • Percent saturation of hemoglobin on the y-axis (0 to 100%)
  • Partial pressure of oxygen on the x-axis
  • Shifts to the right in high CO2 environments (lower affinity)
• What are the adaptations of hemoglobin for efficient oxygen transport?

  • Lower affinity for oxygen in high CO2 environments
  • Higher affinity for oxygen in fetal hemoglobin
  • Conformational changes upon oxygen binding
• How does hemoglobin's function relate to its structure?

  • Hemoglobin's four polypeptides and heme groups allow for oxygen transport
  • Conformational changes enhance oxygen affinity
  • Adaptations enable efficient oxygen delivery to tissues
• What is the relationship between cell respiration and hemoglobin's oxygen affinity?

  • Increased cell respiration raises CO2 levels
  • Higher CO2 lowers pH, reducing hemoglobin's affinity for oxygen
  • Facilitates oxygen release to active tissues
• How does fetal hemoglobin differ from adult hemoglobin in terms of oxygen transport?

  • Fetal hemoglobin has a higher affinity for oxygen
  • Allows fetus to extract oxygen from maternal blood
  • Oxygen dissociation curve shifts to the left compared to adult hemoglobin