2: Normal red cells Flashcards
What organelles do RBCs lack?
Nucleus
Mitochondria
RBCs are flexible, so their ___ ___ must be flexible as well.
cell membrane
to prevent bursting
Which transporter keeps water out of RBCs?
Sodium potassium pump
Na+ OUT and water follows Na+
What do red blood cells require to keep water out of their cytoplasm?
Specialised cell membrane
ATP (to power sodium-potassium pump)
Why must RBCs be broken down?
Lack a nucleus, so therefore lack ability to self-repair
i.e they get less efficient over time - “sell by date”
Where does RBC breakdown occur?
Spleen
What is Hb broken down into?
Amino acids
Iron
Bilirubin
Which hormone controls red blood cell production?
Erythropoeitin
Which organ releases erythropoietin?
In response to what?
Kidney
Hypoxia
What is the action of erythropoietin?
Stimulates RBC production by bone marrow
Which molecule acts as a reducing agent for Fe2+ i.e prevents the oxidation of haemoglobin?
Why is this important?
NADH
If Fe2+ is oxidised to Fe3+ it can’t carry oxygen
What important protein do red blood cells contain?
Haemoglobin
What are the components of adult haemoglobin?
2 alpha subunits
2 beta subunits
One Fe2+ bound to each, meaning each protein can pick up 4 oxygens
To which iron ion can an oxygen molecule bind in haemoglobin?
Fe2+ only
What is the function of haemoglobin?
Oxygen delivery to tissues
By which process do red blood cells produce ATP?
Glycolysis
remember that they have no mitochondria
Which reactive oxygen species can cause damage to DNA and proteins?
Superoxide
Hydrogen peroxide
Which molecule removes reactive oxygen species from red blood cells by converting them to water?
Glutathione
Which enzyme is the rate limiter in glutathione’s removal of reactive oxygen species?
Glucose-6-phosphate dehydrogenase
Most ___ is transported to the lungs by haemoglobin.
CO2
In what form do RBCs carry CO2 to the lungs?
Bicarbonate
When combined with water, CO2 is converted to carbonic acid and subsequently H+ and HCO3- (bicarbonate).
What happens to each of these?
H+ buffered by Hb-
CO2 carried to the lungs in the RBC
What factors shift the oxygen dissociation curve to the RIGHT i.e increase oxygen delivery to tissues?
CADET face RIGHT
Increased carbon dioxide conc.
Acid (so decreased pH)
Increased 2,3-DPG conc.
Exercise
Increased temperature
Foetal haemoglobin has a (greater / smaller) affinity for oxygen than adult haemoglobin at equal oxygen pressures.
greater
What is the structural difference between adult and foetal Hb?
Adult Hb - 2 alpha, 2 beta subunits
Foetal Hb - 2 alpha, 2 gamma subunits
