2. Haemoglobin and RBCs

Question 1

what does the RBC not have

Answer 1

Nucleus
Mitochondria,
Ribosomes

Question 2

benefits of giv ing these up

Answer 2

• Efficient and stable – nothing unnecessary
• Room for haemoglobin
• Unattractive to infecting organisms

Question 3

downsides of giving these things up

Answer 3

No nucleus: No capacity for to making mRNA – no new protein

No Mitochondria no TCA cycle – limits the capacity to generate ATP or reducing power - vulnerable

No Ribosomes no translation of mRNA no protein synthesis

Cant self repair or go through apoptosis due to lack of protein synth + mitochond (needs to be removed by spleen)

Question 4

key parts of the RBC memb

Answer 4

alpha spectrin
ankyrin

Question 5

what can shortage of spectrin cause

Answer 5

eliptical shape

Question 6

if cells cant apoptosis or self repair, then what happens to prevent toxicity

Answer 6

temporary fixing of the membrane

Question 7

why is RBC damage toxic

Answer 7

Hb leakage is highly toxic = aggregates and blocks kidneys

Question 8

what can fibrin strands formed by sepsis cause

Answer 8

acts like cheese wire
slices RBCs

Question 9

how does cell repair after slicing damage

Answer 9

forms vacules
vacuole will pop but reseal
cytoskeleton forms and seals the membrane

Question 10

what are these slicing damaged cells called

Answer 10

keratocytes

Question 11

what forms after damage repair caused by diffuse damage

Answer 11

spherocytes

Question 12

what does defect in memb prtoeins e.g. enykrin cause

Answer 12

hereditary spherocytosis

Question 13

hereditary spherocytosis

Answer 13

• unstable cell memb
• lotsa spherocytes
• anaemia due to breakdown of RBCs
• mild jaundice and gall stones (due to release of RBCs)
• enlarged spleen

Question 14

2 things that allow the sigmoid curve

Answer 14

haem = O2 binding element
globin= surrounding protein element

Question 15

what kind of structure does haem have

Answer 15

porphyrin

Question 16

what do the 2 remaining interaction sites in Fe allow

Answer 16

fixing the molecule to the globin protein
and binding the O2

Question 17

if hb was single chained, what type of O2 release would it be

Answer 17

hyperbolic
O2 only released in sever hypoxia

Question 18

loose and tight conform of globin

Answer 18

• loose binds o2 tightly
• tight gives up O2 easily

Question 19

factors that influence tight and relaxed conforms of globin molecules

Answer 19

pH
CO2
metabolic products

Question 20

why does foetal Hb have higher affinity for O2

Answer 20

doesnt bind 2,3 DPG
so the HbF can compete with mothers Hb, and win
so O2 goes from mum to foetus

Question 21

2 stages of malaria development you shoud know

Answer 21

trophozoites
schizonts

Question 22

when did malaria start affecting humans

Answer 22

10,000 yrs ago during agriculture and stuff
but RBC was fully evolved by this time

Question 23

how is malaria able to survive

Answer 23

is protected from immune system in RBC
and metabolises the Hb for energy

Question 24

4 things that can provide protection from malaria

Answer 24

• Sickle cell
• beta thalassaemia
• G6PD deficiency
• Hb C (mild form of sickle cell)

Question 25

what ishow does a RBC produce reducing power (NADPH)

Answer 25

via hexose monophosphate shunt

Question 26

what is an essential component of hexose monophosphate shuint

Answer 26

G6PD

Question 27

how does G6PD deficiency provide malarial protection

Answer 27

• high oxidative stress and the cell cant deal with it (not enough reducing power)
• so RBC destroyed
• It is thought that if malaria parasites invade a cell with G6PD deficiency then oxidation occurs leading to early destruction of the infected cell.