Haemoglobin Flashcards
1
Q
Role
A
- found in RBC
- carry oxygen around the body
2
Q
Hb
A
- large protein with a quaternary structure
- 4 polypeptide chains
- each chain has a haem group which contains an iron ion and gives Hb its red colour
3
Q
Oxyhaemoglobin
A
- oxygen joins to Hb in RBC to form
- reversible reaction
- near body cells oxygen leaves oxyHb and returns back to just being Hb
4
Q
Process Of Joining
A
- oxygen joining to Hb = association or loading
- oxygen leaves OxyHb = dissociation or unloading
- Hb + 402 reversible arrow HbO8
5
Q
Affinity for oxygen and partial pressure of oxygen
A
- Hb affinity depends on conditions its in like pO2
- pO2 measure of oxygen concentration the greater the concentration of dissolved oxygen in cells the higher the partial pressure
- so as pO2 increases Hb affinity also increases so oxygen loads onto Hb to form OxyHb where there’s high pO2
- OxyHb unloads its oxygen where there’s a lower pO2
6
Q
Affinity
A
-tendency a molecule has to bind with oxygen
7
Q
High pO2
A
-oxygen enters blood capillaries at alveoli where there’s a high pO2 so it loads
8
Q
Low pO2
A
-when cells respire they use up oxygen so there’s a lower pO2 so RBC deliver oxyhb to respiring tissues where the oxygen is unloaded the hb then returns to lungs to pick up more O2
9
Q
Alveoli
A
- high O2 conc
- high pO2
- high affinity
- oxygen loads
10
Q
Respiring Tissue
A
- low O2 conc
- low pO2
- low affinity
- O2 unloads
11
Q
Dissociation curves
A
- shows how saturated the Hb is with O2 at any given pO2
- affinity of hb for O2 affects how saturated Hb is
- where pO2 high hb has high affinity for O2 so high saturation for oxygen
- low pO2 hb has low affinity for O2 so low saturation of O2
12
Q
Saturation
A
- when hb combines with first oxygen its shape alters in a way that makes it easier for other oxygen molecules to join too
- hb starts to become more saturated which makes it harder for the more oxygen to join
13
Q
carbon dioxide concentration
A
- pCO2 affects oxygen unloading
- hb gives up its oxygen more readily at higher pCO2 as its a way of getting more oxygen to cells during activity
14
Q
Bohr Effect
A
- when cells respire they produce CO2 which raises pCO2 increasing the rate of oxygen unloading so the dissociation curve shifts to the right
- saturation of blood lower for given pCO2 as more oxygen is being released so its called bohr effect
15
Q
Low oxygen environments
A
- hb with higher affinity for oxygen then human hb
- isn’t much oxygen available so hb needs to be good at loading any available oxygen
- curve shifts left
16
Q
high activity levels
A
- very active and high oxygen demands have hb with lower affinity for oxygen than human hb
- need hb top easily unload oxygen
- curve to right
17
Q
size
A
- smaller mammals tend to have a higher SA to volume ratio than larger mammals
- so lose heat quickly
- high metabolic rate to help them keep warm
- high oxygen demand
- mammals smaller than humans have hb with lower affinity for oxygen so they need hb to easily unload oxygen to meet their high oxygen demand
- curve shifts to the right
