Red Blood Cells

• What is the main function of red blood cells (RBC)?

  To carry and deliver oxygen with the help of protein hemoglobin
• What additional components do red blood cells need to survive in circulation aside from hemoglobin?

  An intact membrane, an energy source, and a protector
• What is the size range of red blood cells?

  6 to 8 µm in diameter
• What are the volume classifications of red blood cells?

  • Normocytic: 80 to 100 fL
  • Microcytic: lower than 80 fL
  • Macrocytic: higher than 100 fL
• What is the lifespan of red blood cells?

  120 days
• What is the shape of red blood cells and why is it important?

  Biconcave shape, which supports deformation to carry and release oxygen and navigate tiny vessels
• Why do red blood cells need to be deformable?

  To carry and release oxygen and to pass through tiny vessels
• What is the significance of the pale area in red blood cells?

  It provides extra surface area for stretching and passing through narrow capillaries and vessels
• How does aging affect red blood cells?

  They lose membrane surface area, making them susceptible to lysis and unable to pass through tiny vessels
• What internal components do red blood cells lack?

  Nucleus, ribosome, mitochondria, and other organelles
• What is observed under Wright's stain in red blood cells?

  Only the reddish to pinkish color cytoplasm, indicating the presence of hemoglobin
• What are the components of the red blood cell membrane?

  • Carbohydrates
  • Lipids
  • Proteins
• What metabolic activity is associated with red blood cells?

  Glycolytic activity or pathways
• How can red blood cells be destroyed?

  • Extravascularly
  • Intravascularly
• What are the functions of the erythrocyte membrane?

  • Maintain cell shape and deformability
  • Maintain osmotic balance
  • Support surface antigens and receptors
  • Transport essential cellular ions and gases
• What is the composition of the erythrocyte membrane?

  52% Proteins, 40% Lipids, and 8% Carbohydrates
• What are the main lipid components of the red cell membrane?

  Cholesterol and phospholipids
• How do lipids contribute to red blood cells?

  They are essential for movement and permeability of the RBCs
• What is the structure of the red cell membrane with regards to lipids?

  It is a bilayer with equal parts of phospholipids and cholesterol
• What happens to the red cell membrane as cholesterol concentration increases?

  The membrane becomes stronger
• What is the role of LCAT in red blood cells?

  It facilitates the exchange of cholesterol within the cell membrane and plasma
• What happens if there is too much cholesterol in red blood cells?

  The red cell’s elasticity is lost
• What are the functions of integral or transmembrane proteins in red blood cells?

  • Serve as receptor sites for substances
  • Act as transport and adhesion sites
  • Serve as signaling receptors
• What can deficiencies in integral proteins lead to?

  Loss of red cells deformability, problems with adhesion, or cellular activity abnormalities
• What is the role of GPI Anchor in red blood cells?

  • Binds around 30 proteins
  • Protects red cells from lysis caused by complement
• What is Paroxysmal Nocturnal Hemoglobinuria (PNH)?

  A condition causing red cell destruction due to complement
• What is the function of the membrane enzyme system in red blood cells?

  • Facilitates movement of substrates and cofactors
  • Maintains osmotic balance to prevent lysis
• What is the role of Sodium-Potassium ATPase in red blood cells?

  Controls the transport of sodium and potassium across the membrane
• What is the intracellular ratio of sodium to potassium in red blood cells?

  1. 12
• What is the extracellular ratio of sodium to potassium in red blood cells?

  25:1
• What substances are red blood cells permeable to?

  Water, bicarbonates, and chloride
• What is the function of Aquaporin 1 in red blood cells?

  Forms pores for inward water flow in response to osmotic changes
• What does Calcium ATPase do in red blood cells?

  Moves calcium out of the cell to plasma against a concentration gradient
• What is required for the entry or exit of ions in red blood cells?

  Energy (ATP) must be consumed
• How can membrane proteins be extracted from red blood cells?

  • Using Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-Page)
  • Separated based on molecular weight and net charge
• What staining methods are used to identify membrane proteins?

  Periodic acid-Schiff (PAS) or Coomassie blue
• What is the role of peripheral or cytoskeletal proteins in red blood cells?

  • Provides shape and deformability
  • Acts as a supporting framework for the lipid bilayer
• What are some examples of skeletal proteins in red blood cells?

  Actin, adducin, tropomodulin, dematin, and ankyrin
• How do red blood cells obtain energy?

  From carbohydrates, especially glucose, in circulation
• What happens to glucose once it enters the red blood cell?

  It undergoes glycolysis, either anaerobic or aerobic