transport of oxygen

Question 1

what is haemoglobin

Answer 1

the red pigment used to transport thee oxygen in the blood.

Question 2

what is association

Answer 2

the binding of two molecules, commonly used in biology when referring to the bonding of oxygen onto haemoglobin

Question 3

why can haemoglobin transport oxygen

Answer 3

because the reaction is reversible- the reverse reaction is called dissociation so that oxygen can be used in respiration.

Question 4

whats dissociation

Answer 4

the separation of two molecules, used in biology when referring to the unloading of oxygen from haemoglobin

Question 5

binding of the first o2 molecule causes a…

Answer 5

conformational change in the haemoglobin molecule

Question 6

what does the conformational change do

Answer 6

the conformational change makes the haem groups more accessible to oxygen

Question 7

why is the gradient of the graph initially shallow on the oxygen dissociation graph

Answer 7

cus the haem groups are all unbound and held tightly within the haemoglobin

Question 8

once the first haem group binds…

Answer 8

positive cooperativity causes the gradient to increase steeply

Question 9

why does the curve plateau

Answer 9

cus its less likely for an oxygen molecule to collide with the last empty site on each haemoglobin molecule

Question 10

talk about foetal haemoglobin

Answer 10

has a higher affinity for oxygen than adult haemoglobin to ensure it gains enough oxygen

Question 11

talk about animals living at a high altitude and their haemoglobin

Answer 11

animals that live at high altitude have a higher affinity for o2 than those that live at lower altitudes

Question 12

what is co2 released from and transported by

Answer 12

co2 is released from respiring tissues and transported by the blood to lungs for excretion

Question 13

5% of CO2 …

Answer 13

transported is dissolved in the blood plasma

Question 14

10% of co2…

Answer 14

transported is combined with haemoglobin to form carbaminohaemoglobin
CO2+Hb carbaminohaemoglobin

Question 15

85% of co2…

Answer 15

is transported as hydrogen carbonate ions dissolved in blood plasma (HCO3-)

Question 16

talk about the formation of hydrogen carbonate (HCO3-)

Answer 16

• CO2 diffuses into red blood cells and combines with water to form carbonic acid (H2CO3)
• carbonic acid dissociates (splits up) to form hydrogen carbonate and a hydrogen ion. H2CO3H+ + HCO3-

Question 17

where does hydrogen carbonate go after diffusing out the cell

Answer 17

its transported around the body to the lungs

Question 18

what happens when HCO3 leaves the cell a lot

Answer 18

it causes the cell to become positive which is bad as they need to maintain charge

Question 19

how does a cell rebalance when HCO3 leaves the cell

Answer 19

chloride ions diffuse in to balance the charge from the loss of hydrogen carbonate ions- this is called the chloride shift

Question 20

what is the chloride shift

Answer 20

the movement of chloride ions into the erythrocytes to balance the charge as hydrogen carbonate ions leave the cell

Question 21

what can haemoglobin act as

Answer 21

haemoglobin acts as a buffer by taking up the hydrogen ions produced by the dissociation of carbonic acid

Question 22

what effect does co2 have on haemoglobin

Answer 22

has an effect on the ability of haemoglobin to transport oxygen

Question 23

whats the bhor effect

Answer 23

the effect that increasing co2 concentration has on haemoglobin explaining how oxygen is released where its needed

Question 24

its important that at the lungs:_________
but at the tissues:________

Answer 24

at the lungs: oxygen is taken onto haemoglobin
but at the tissues: oxygen can be released and co2 to join

Question 25

what happens when co2 dissolves in the cytoplasm

Answer 25

when it dissolves in the cytoplasm of red blood cells to form carbonic acid which dissociates to produce H+, co2 then combines with water forming carbonic acid- carbonic acid then dissociates into H+ and hydrogen carbonate

Question 26

what do H+ ions do for haemoglobin

Answer 26

lower the pH of the cytoplasm which affects the tertiary structure of haemoglobin
then
haemoglobin affinity for oxygen is reduced at lower pH and so oxygen is reduced at lower pH and so oxygen is unloaded in respiring tissues

Question 27

respiring tissues produce CO2 causing…

Answer 27

causing HCO3- to form and H+&raquo_space; makes haemoglobin release O2 to tissue. lowers affinity- cells use it for respiration