Haemoglobin

Question 1

Role

Answer 1

• found in RBC

- carry oxygen around the body

Question 2

Hb

Answer 2

• 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

Question 3

Oxyhaemoglobin

Answer 3

• oxygen joins to Hb in RBC to form
• reversible reaction
• near body cells oxygen leaves oxyHb and returns back to just being Hb

Question 4

Process Of Joining

Answer 4

• oxygen joining to Hb = association or loading
• oxygen leaves OxyHb = dissociation or unloading
• Hb + 402 reversible arrow HbO8

Question 5

Affinity for oxygen and partial pressure of oxygen

Answer 5

• 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

Question 6

Affinity

Answer 6

-tendency a molecule has to bind with oxygen

Question 7

High pO2

Answer 7

-oxygen enters blood capillaries at alveoli where there’s a high pO2 so it loads

Question 8

Low pO2

Answer 8

-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

Question 9

Alveoli

Answer 9

• high O2 conc
• high pO2
• high affinity
• oxygen loads

Question 10

Respiring Tissue

Answer 10

• low O2 conc
• low pO2
• low affinity
• O2 unloads

Question 11

Dissociation curves

Answer 11

• 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

Question 12

Saturation

Answer 12

• 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

Question 13

carbon dioxide concentration

Answer 13

• 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

Question 14

Bohr Effect

Answer 14

• 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

Question 15

Low oxygen environments

Answer 15

• 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

Question 16

high activity levels

Answer 16

• 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

Question 17

size

Answer 17

• 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