Study Set Content:
What following conditions are necessary for the RBC to survive for 120 days?
- The red cell membrane must be deformable
- Hemoglobin Structure and function must be adequate
- The red cell metabolic pathways must be active
True or False:
If the RBC is immature, it becomes less deformable
False; RBCs become less deformable when they are aged/old/senescent
What removes aged/old/senescent RBCs?
Splenic Macrophages
Functions of RBC membrane
- Separates intracellular from extracellular fluid
- Allows nutrient and ion passage selectively (selective permeability)
- Allows cell to deform when needed
RBC Membrane are influenced by:
- Cell Shape
- Cytoplasmic Viscosity
- Membrane deformability and stability
What makes up surface antigen?
Glycolipids
What are the two types of Proteins?
Integral Proteins and Peripheral Proteins
Are membrane proteins that extend from the outer surface and traverse the entire membrane to the inner cytoplasmic site of RBCs:
Integral Proteins
What proteins are situated right beneath the inner leaflet?
Peripheral Proteins
The semi-permeable lipid bilayer is supported by a what:
Mesh-like cytoskeleton
Give the respective percentage to the following:
CHON (Protein) -
Lipids -
CHO (Carbohydrates)
CHON - 52%
Lipids - 40%
CHO - 8%
How many RBC antigens have been identified?
Over 300
These are present in nearly equimolar quantities
Phospholipids and unesterified cholesterol
What are present in small quantities?
Free fatty acids and Glycolipids
What comprises the External Surface or the outer leaflet?
- Phosphatidylcholine
- Sphingomyelin
- Glycolipids
Hint: You can use the mnemonics, "SPG"
S - Sphingomyelin
P - Phosphatidylcholine
G - Glycolipids
What comprises the Internal Surface or the inner leaflet?
- Phosphatidylethanolamine
- phosphatidylinositol
- Phosphatidylserine
Mnemonics: PPP
Phospholipids that are situated on the outer leaflet are collectively called
Choline Phospholipids
Represents the controlling points in the major pathways of lipid renewal.
Choline Phospholipids
Are the gateways in the entry of phospholipids
Phosphatidylcholine & Sphingomyelin
Also known as flippase
Aminophospholipid translocase (ATP-dependent enzyme)
