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A level Biology: Post your doubts here!

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How's your preparation going ?
Btw have you practiced plan diagrams for Q2 of p3's ?
Honestly, not too well. What about you? In sha Allah,I hope Ill study better.
A few things yeah.. :3 <the root and stem ones> not recently though. You?
P2 needs alot of attention at the moment. :)
 
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Honestly, not too well. What about you? In sha Allah,I hope Ill study better.
A few things yeah.. :3 <the root and stem ones> not recently though. You?
P2 needs alot of attention at the moment. :)
ummm..Cant say anything at this stage , isA
ikr but i have 3 other subjects as well :/ n time is running like water -_-
 
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Are you sure ?
Then why they have given the questions in P1. I cant recall but there were some questions from this topic in 07 paper.
I'll post them tomorrow. :) Thankyou
Like I said, It is not in our syllabus NOW( acc to my teacher). I guess the syllabus changed in 2009 or something
 
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Like I said, It is not in our syllabus NOW( acc to my teacher). I guess the syllabus changed in 2009 or something
Are you sure ?
Then why they have given the questions in P1. I cant recall but there were some questions from this topic in 07 paper.
I'll post them tomorrow. :) Thankyou

Hey check the syllabus:
http://www.cie.org.uk/images/128589-2015-syllabus.pdf
It doesnt say anything about... Tidal calculations....for Gaseous Exchange for 2015 :)


<Oh and the epidemiological and experimental evidence linking cigarette smoking....is there :p Hehe>
 
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Hey check the syllabus:
http://www.cie.org.uk/images/128589-2015-syllabus.pdf
It doesnt say anything about... Tidal calculations....for Gaseous Exchange for 2015 :)


<Oh and the epidemiological and experimental evidence linking cigarette smoking....is there :p Hehe>

ohh yeah THANKGOD :X3: THANKSSSSS(y)

shitt man...i hate that topic from the bottommmmmmmmmmmmm of my heart :mad: I cant even understand the wording of questions related to it.:oops:
 
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I tried to look at the MS and write an answer <.<

http://freeexampapers.com/A-Level/Biology/CIE/2010-Nov/9700_w10_qp_21.pdf
question 3 part c
Hows this?
At high altitude pCO2 would be lower than at seas level which means that Hb would be less saturated.If haematrocrists increase whihc is more number of RBCs
the RBCs can compensate for the low pO2.

http://freeexampapers.com/A-Level/Biology/CIE/2010-Nov/9700_w10_qp_22.pdf
question 6 part d
The gases diffuse down the concentration gradient. In the pulmonary artery the pO2 i slower than in the alveolous in the alveolus it is 13.87 kPa. This oxygen diffuses into teh blood from the alveolus.When the artery that carries oxygen rich blood reaches near the respiring tissue there the pCO2 in capillary network is low at the arteriol end.Thus CO2 diffuses out of the tisues and into the blood.
 
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7 What maintains the diffusion gradient for the diffusion of oxygen out of an alveolus?

1 binding of oxygen with haemoglobin to form oxyhaemoglobin
2 blood flow bringing a new supply of red blood cells
3 increased surface area of red blood cells as they are forced through narrow capillaries
4 complete replacement of the air in the alveolus with each breath

A 1, 2 and 3 only
B 1, 2 and 4 only
C 2 and 3 only
D 3 and 4 only

Answer is A.Why is the fourth point not correct?
 
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7 What maintains the diffusion gradient for the diffusion of oxygen out of an alveolus?

1 binding of oxygen with haemoglobin to form oxyhaemoglobin
2 blood flow bringing a new supply of red blood cells
3 increased surface area of red blood cells as they are forced through narrow capillaries
4 complete replacement of the air in the alveolus with each breath

A 1, 2 and 3 only
B 1, 2 and 4 only
C 2 and 3 only
D 3 and 4 only

Answer is A.Why is the fourth point not correct?

Statement 4 is not correct because it simply does not occur. Air in the alveolus is not completely replaced in one breath. Rather, some air always remains.

Although a bit beyond our level, here's a site:

http://faculty.stcc.edu/AandP/AP/AP2pages/Units21to23/respiration/alveolar.htm

A quote from the site:

"Because the amount of air that never leaves the respiratory tract is so large (over a liter!), the spaces in the respiratory tract can never totally empty out and be completely replaced by atmospheric air. So the alveolar air is a mixture of atmospheric air and functional residual capacity air."
 
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