A level Biology: Post your doubts here!

[My Name]

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.

 

[shinnyyy]

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 -_-

 

[My Name]

ummm..Cant say anything at this stage , isA
ikr but i have 3 other subjects as well :/ n time is running like water -_-

In sha Allah!
Yes time :/ and I find it hard to concentrate.

 

[shinnyyy]

In sha Allah!
Yes time :/ and I find it hard to concentrate.

:/ ahh why ?

 

[My Name]

:/ ahh why ?

I get distracted very easily with just anything.

 

[princess Anu]

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

 

[My Name]

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 Hehe>

 

[shinnyyy]

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 Hehe>

ohh yeah THANKGOD THANKSSSSS

shitt man...i hate that topic from the bottommmmmmmmmmmmm of my heart I cant even understand the wording of questions related to it.

 

[My Name]

ohh yeah THANKGOD THANKSSSSS

shitt man...i hate that topic from the bottommmmmmmmmmmmm of my heart I cant even understand the wording of questions related to it.

Welcome
Right now I dont know what to hate what not to

 

[My Name]

November 2012 paper 2 question 5 part c ii
http://freeexampapers.com/A-Level/Biology/CIE/2012-Nov/9700_w12_qp_21.pdf
Plz and thnx

 

[shinnyyy]

November 2012 paper 2 question 5 part c ii
http://freeexampapers.com/A-Level/Biology/CIE/2012-Nov/9700_w12_qp_21.pdf
Plz and thnx

I guess it's bcoz in the aorta the blood is pumped continously to the systemic circulation therefore the BP varies from 11 to 16 whereas in the left ventricle there is ventricular diastol where the ventricle is empty and they ventricular filling then ventricular systolic therefore the bp drops to 0 and increase to 16.

 

[shinnyyy]

Welcome
Right now I dont know what to hate what not to

Are you done with ch 14 immunity?

 

[My Name]

Are you done with ch 14 immunity?

I did try. Why?

 

[My Name]

http://freeexampapers.com/A-Level/Biology/CIE/2010-Jun/9700_s10_qp_22.pdf
Quetsion 2 c
I just wrote that :
Teh oxygenated blood from aorta and deoxygenated blood from pulmonary artery mix!
The blood reaching the lungs is a mix.

Plz explain

 

[My Name]

http://freeexampapers.com/A-Level/Biology/CIE/2012-Jun/9700_s12_qp_21.pdf
question 3 part b

 

[My Name]

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.

 

[My Name]

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?

 

[My Name]

There was a question in may June 2014 var 22 regarding that so it's obvious that we have to know about that.

Yeah I have read. Thanks

There's some error in papers section so I'll take a snap from my past papers booklet and will give u tomorrow okz????

You were talking about this paper?

 

[qwertypoiu]

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."

 

[qwertypoiu]

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.

Question 3 c says: "Describe the role of haemoglobin in the transport of oxygen and carbon dioxide."

You seem to be answering a different question

Question 6: A few grammatical mistakes but your answer seems good to me. However, it seems like you have made three points, whilst the question has 4 marks. The mark scheme shows the first general statement you made as one mark. Next, you made one statement for each table, so you got two from that.
Each table has two rows ( 2 marks) so you could have made two more points. (or one would've been enough)