1 - normal erythropoiesis

Question 1

what are some components of red blood cell structure?

Answer 1

• complex membrane structure made of protein spars and anchors allowing RBCs to be flexible
• no nucleus or mitochondria
• high surface area to volume ratio for gas exchange
• full of haemoglobin to carry oxygen

Question 2

what is haemoglobin structure?

Answer 2

4 subunit protein with 1 haem (flat porphyrin ring combined w Fe2+) per subunit

4 oxygen per haemoglobin (as 1 O2 attaches to 1 Fe2+)
*oxygen can only bind to Fe2+ (ferrous ion) and not Fe3+ (ferrous ions)

Question 3

what regulates production of red blood cell?

Answer 3

kidneys act as oxygen sensor (ask if enough oxygen transported to tissues). if too low then respond by making epo (erythropoietin) which goes to bone marrow & promotes RBC production

Question 4

what happens in red blood cell destruction?

Answer 4

after about 120 days spleen removes RBCs from circulation and macrophages in spleen eat them up

components of RBC recycles
- globin chains recycled as amino acids
- haem group broken down to iron & bilirubin, which is taken to liver to conjugated and then excreted in bile

Question 5

what are the ideal things that red blood cells want? and how are these achieved?

Answer 5

1. way to generate ATP = glycolysis
2. way to prevent Fe2+ from turning to Fe3+ (in form good for binding oxygen) = NADH acts as electron donor
3. prevent oxidative damage from free radicals (from excess oxygen) = glutathione
4. way of holding onto oxygen and dump at hypoxic tissues = allosteric effect

Question 6

what is rate limiting enzyme of glycolysis? why important?

Answer 6

glucose-6-phosphate dehydrogenase (G6PD), its also needed to make glutathione & NADPH which is whats needed to prevent damage by free radicals

this can be problem as G6PD is x-linked so in males if mutation then lots problems

Question 7

how is carbon dioxide transported?

Answer 7

10% dissolved in solution, 30% bound to Hb, 60% as bicarbonate

Question 8

what can change the shape of oxygen saturation curve?

Answer 8

small molecules like CO2, H+ and 2,3, BPG can go in and stick to globin subunit altering position of haem and ability of oxygen to bind. this changes shape of curve to right (drops off more oxygen to tissues)