haemoglobin

Question 1

hemoglobin

Answer 1

complex protein with quaternary structure composed of four subunits each with a haem group

Question 2

product of oxygen and haemoglobin

Answer 2

oxyhaemoglobin

Question 3

definition of partial pressure of oxygen

Answer 3

amount of oxygen in a mixture of gases

Question 4

define loading and unloading

Answer 4

loading- oxygen is taken u by hemoglobin
unloading-oxygen is released by hemoglobin

Question 5

name of oxygen dissociation curve

Answer 5

sigmoid curve

Question 6

co-operative nature of oxygen loading

Answer 6

first O2 molecule alters the tertiary structure of Hb, exposes the 2nd and 3rd binding sites
makes it easier for 2nd and 3rd O2 molecule to bind and load

Question 7

what is the effect of increased respiration on oxygen dissociation

Answer 7

1. tissue cells respire aerobically, quickly reducing O2 in the surrounding tissue
2. reduces the pO2 to a lower level
3. oxygenated blood arriving will unload more oxygen to the tissue cells
4. surrounding pO2 is lower so haemoglobin will have an even lower affinity to oxygen

Question 8

Effect of CO2 conc

Answer 8

in higher than normal pCO2, hemoglobin’s affinity for O2 is even lower
more unloading of O2
curve shift to the right

Question 9

Heat from respiration helps mammals to maintain a constant body temperature.

Use this information to explain the relationship between the surface area to volume ratio of mammals and the oxygen dissociation curves of their haemoglobins. (5)

Answer 9

Smaller mammal= larger SA:Vol ratio more heat lost
larger SA:Vol ratio has greater rate of respiration
Oxygen required for aerobic respiration
more oxygen unloading

Question 10

how are animals different that live in areas of low pO2? (high altitudes and bottom of lakes) also foetuses

Answer 10

• curve shifts to the left
• higher affinity for O2
• fully saturated at lower pO2 and rapidly unloads its oxygen when the haemoglobin passes into the tissues

Question 11

animals with high respiration or large SA:V ratio

Answer 11

• lower affinity for O2
• so unloads from the haemoglobin more readily
• O2 is more readily available to respiring cells

Question 12

The oxygen dissociation curve of the foetus is to the left of that for its mother.

Explain the advantage of this for the foetus

Answer 12

1. Higher affinity so loads more oxygen
2. Same partial pressure
3. Oxygen moves from mother to foetus

Question 13

Explain how oxygen is loaded, transported and unloaded in the blood. (6)

Answer 13

1. Haemoglobin has a high affinity for oxygen
2. In red blood cells
3. Loading in lungs
4. at high p.O2
5. Unloads to respiring cells/tissues
6. at low p.O2
7. Unloading linked to higher carbon dioxide