Untitled Quiz

Study Notes

RBCs are small, 6-8μm in diameter, with a bag-like structure filled with hemoglobin (95%).
RBCs lack nuclei and nucleic acids and are unable to reproduce.
RBCs lack cell organelles, such as mitochondria, Golgi, ER, and lysosomes, limiting their synthetic activities.
RBCs do not synthesize proteins, lipids, or carbohydrates.
RBC function: Transports oxygen from the lungs to peripheral tissues, and CO2 from tissues back to the lungs.
RBCs are highly deformable for easy movement through the circulatory system.

RBCs are not true cells.
RBC metabolism requires energy for maintaining membrane phospholipid distribution, skeletal protein deformability, functional Hb, and protecting cell proteins from oxidative damage.
RBCs rely on glucose as their primary energy source.
ATP is produced solely through anaerobic glycolysis, producing lactate as a byproduct.

RBCs contain about 35% solids.
Hemoglobin is the primary protein in RBCs.
Other proteins, lipids, and oligosaccharide chains form the stroma and cell membrane.
RBCs have higher concentrations of potassium (K), magnesium (Mg), and zinc (Zn) than plasma.

RBCs lack mitochondria, preventing aerobic respiration, citric acid cycle, and fatty acid or ketone body oxidation.
ATP is produced solely through glycolysis, yielding 2 ATP molecules per glucose molecule.
Lactate is a byproduct of anaerobic glycolysis and can be used in gluconeogenesis.

ATP is used to maintain the RBC's biconcave shape.
ATP regulates ion and water transport via the Na+-K+-ATPase and anion exchange protein.

Glucose enters RBCs through facilitated diffusion via GLUT-1 transporters.
GLUT-1 transporters are insulin-independent, meaning glucose uptake isn't influenced by insulin levels.
GLUT-1 creates a gated pore in the membrane allowing glucose passage.
GLUT-1 transports glucose down its chemical gradient, facilitating uptake into the cell.
Intracellular glucose is quickly converted into glucose-6-phosphate (G6P) for glycolysis or the pentose phosphate pathway (PPP).
Increasing intracellular ATP levels inhibit glucose uptake, creating a negative feedback loop.
GLUT-1 also transports dehydroascorbic acid (DHA), an oxidized form of vitamin C, used to balance intracellular redox reactions.

Provides energy for the cells via ATP production.
Provides NADH for the reduction of methaemoglobin by NADH-cytochrome b5 reductase.

Deficiency in glucose-6-Phosphate dehydrogenase (G6PD) can lead to haemolytic anaemia.
Glucose-6-Phosphate deficiency results in the buildup of free radical and oxidative stress, damaging the cell and leading to haemolysis.