# Gas exchange question!!! watch

1. How many phospholipid bilayers does oxygen pass through in diffusing from an alveolar air space to form oxyhaemoglobin in a red blood cell in a mammalian lung?

A 3
B 5
C 6
D 9
2. Alveoli are one cell thick, and lie side by side. That means oxygen would diffuse in one side and then out the other, from inside the alveoli to out. The oxygen diffuse into red blood cells across a membrane, but needs to diffuse into the blood vessel to get to the RBC.
My understanding would therefore be 5, but there is a possibility that this is wrong
(When you find out the answer could you post it here- is quite like to know)
Alveoli are one cell thick, and lie side by side. That means oxygen would diffuse in one side and then out the other, from inside the alveoli to out. The oxygen diffuse into red blood cells across a membrane, but needs to diffuse into the blood vessel to get to the RBC.
My understanding would therefore be 5, but there is a possibility that this is wrong
(When you find out the answer could you post it here- is quite like to know)
For what exactly?
4. (Original post by Skkkk)
For what exactly?
Sorry what do you mean XD
The answer to the question is what I'd like to know as a certain this is just my best guess
Sorry what do you mean XD
The answer to the question is what I'd like to know as a certain this is just my best guess
Also the questions a bit tricky as I'm not sure if it counts oxygen going through the membrane into the cell and going through the membrane out of the same cell as one phospholipid bilayer or two
Alveoli are one cell thick, and lie side by side. That means oxygen would diffuse in one side and then out the other, from inside the alveoli to out. The oxygen diffuse into red blood cells across a membrane, but needs to diffuse into the blood vessel to get to the RBC.
My understanding would therefore be 5, but there is a possibility that this is wrong
(When you find out the answer could you post it here- is quite like to know)
Seconding this
2 (alveolar cell) + 2 (capillary wall) + 1 (RBC) = 5
Alveoli are one cell thick, and lie side by side. That means oxygen would diffuse in one side and then out the other, from inside the alveoli to out. The oxygen diffuse into red blood cells across a membrane, but needs to diffuse into the blood vessel to get to the RBC.
My understanding would therefore be 5, but there is a possibility that this is wrong
(When you find out the answer could you post it here- is quite like to know)
Your answer is correct!. It is 5. however i would be grateful if u explain it to me in more detail tho
8. (Original post by dajjal619)
Your answer is correct!. It is 5. however i would be grateful if u explain it to me in more detail tho

1) Alveoli wall and cappliary wall are both one cell thick. This is important for the question. Without this knowledge, the question is hard to solve.
2) oxygen has to enter the cell, move through it, and then leave on the other side to get from the alveoli to the capillary. This counts as 2 bilayers.
3) this happens twice, as oxygen moves through the alveolus wall AND the capillary wall (which are both one cell thick). When oxygen is in the capillary, it has passed through 4 bilayers total (2 through alveolus wall, and 2 through capillary wall)
4) the oxygen then needs to get into the red blood cell, which obviously has a partially permeable cell surface membrane (which is a bilayer). This requires oxygen to move through one layer, because oxygen is not leaving the red blood cell afterwards
5) to summarise,
first movement - into alveolus wall,
second movement- out of alveolus wall
Third movement - into capillary wall
Fourth movement - out of capillary wall
Fifth movement - into red blood cell
(When I say movement I mean across a phospholipid bilayer)
Hope this makes some sense fell free to ask for more confirmation and I'll see what I can do

1) Alveoli wall and cappliary wall are both one cell thick. This is important for the question. Without this knowledge, the question is hard to solve.
2) oxygen has to enter the cell, move through it, and then leave on the other side to get from the alveoli to the capillary. This counts as 2 bilayers.
3) this happens twice, as oxygen moves through the alveolus wall AND the capillary wall (which are both one cell thick). When oxygen is in the capillary, it has passed through 4 bilayers total (2 through alveolus wall, and 2 through capillary wall)
4) the oxygen then needs to get into the red blood cell, which obviously has a partially permeable cell surface membrane (which is a bilayer). This requires oxygen to move through one layer, because oxygen is not leaving the red blood cell afterwards
5) to summarise,
first movement - into alveolus wall,
second movement- out of alveolus wall
Third movement - into capillary wall
Fourth movement - out of capillary wall
Fifth movement - into red blood cell
(When I say movement I mean across a phospholipid bilayer)
Hope this makes some sense fell free to ask for more confirmation and I'll see what I can do
Bruv. thats the best explanation i ever got on this site!. Dude do answer my other questions whenever i post. Thanks !!
10. (Original post by dajjal619)
Bruv. thats the best explanation i ever got on this site!. Dude do answer my other questions whenever i post. Thanks !!
Haha sure thing man - anytime
Haha sure thing man - anytime
I just posted one more question. Please do help me there as well

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