Mass Transport: Animals

Question 1

Haemoglobin

Answer 1

Protein molecule with 4 polypeptide chains containing 4 haem groups, that transports oxygen

Question 2

Haem group

Answer 2

contains ferrous/ fe2+ ion, each of which can combine with a single O2 so therefore 4 O2 molecules can be carried by a single haemoglobin molecule

Question 3

Loading

Answer 3

aka Associating- when haemoglobin binds with oxygen.
occurs in the lungs

Question 4

Unloading

Answer 4

aka dissociating- when haemoglobin releases its oxygen .
takes place in the tissue.

Question 5

High affinity

Answer 5

hb with high affinity takes up oxygen more easily but releases it less easily.

Question 6

Low affinity

Answer 6

hb with low affinity for oxygen takes it up less easily but release it more easily.

Question 7

How is hb efficient at transporting o2?

Answer 7

readily associates with oxygen at the surface where gas exchange takes place.
readily dissociates from oxygen at the tissue requiring it

Question 8

Can hb change its affinity?

Answer 8

Yes, it is able to change shape in the presence of certain substances such as CO2.

Question 9

Conditions at gas exchange surfaces

Answer 9

1) O2 concentration is high
2) CO2 concentration is low
3) affinity is high so oxygen is associated

Question 10

Conditions at respiring tissue

Answer 10

1) O2 concentration is low
2) CO2 concentration is high
3) affinity is low so oxygen is dissociated

Question 11

Why are there different types of hb affinity?

Answer 11

Different species have hb made up of different seq of amino acid, so different tertiary and quaternary structure, so different ability to bind to oxygen

Question 12

Oxygen dissociation curve

Answer 12

show the affinity of haemoglobin for oxygen
in certain conditions

show the relationship between oxygen levels (as partial pressure) and haemoglobin saturation

Question 13

Cooperative binding

Answer 13

1st O2 binds, chnages quarternary shape, easier for next O2 to bind, easier for next.
4th binding hard as only one empty subunit.

Question 14

Behaviour of hb at gas exchange surface (lungs)

Answer 14

> low co2
affinity for O2 increased
high O2 in lungs
oxygen more readily loaded by hb
curve more to the left

opposite at respiring tissue/muscles

Question 15

Effect of CO2 on hb

Answer 15

dissolved carbon dioxide is acidic and the low pH causes hb to change shape

Question 16

The more active a tissue, the more O2 is unloaded. why?

Answer 16

-high rate of respiration
-more co2
-lower ph
-shape change
-low affinity
-O2 unloaded more readily
-more O2 available for respiration

Question 17

When partially filled hb reaches tissue with low respiratory rate..

Answer 17

only 1 oxygen molecule is released

Question 18

How many oxygens released at highly respiring tissue?

Answer 18

3

Question 19

Species of animals with low partial pressure of oxygen

Answer 19

have hb with higher affinity of oxygen
Oxd curve to the left