A level Biology: Post your doubts here!

[wizzzzzzzzzzzzzzzzz]

http://papers.xtremepapers.com/CIE/...and AS Level/Biology (9700)/9700_w08_qp_1.pdf
Auestion 1
How to solve this kind of questions ??

 

[My Name]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w08_qp_1.pdf
Auestion 1
How to solve this kind of questions ??

Hi
What we need to know is that...Total magnification= eyepiece x objective.
So for
A 50,B 100,C 200,D 400.
Obviously you know that greatest magnification you will see less cells.
So least maginification greatest number of cells,here is in A.Therefore answer is A.

 

[The Godfather]

guys any last minutes tips plz

 

[The Godfather]

i need help or else i will flunk in tomorows paper

 

[SadiaMaryam]

i need help or else i will flunk in tomorows paper

if you couldn't prepare well before. You may go through the coursebook chapters in the time left till tomorrow's paper.
If u think u can't read the whole chapters now, then just read important like highlighted points, or read summaries of chapters.

 

[My Name]

i need help or else i will flunk in tomorows paper

Check these post:
https://www.xtremepapers.com/commun...st-your-doubts-here.9858/page-260#post-913723
https://www.xtremepapers.com/commun...st-your-doubts-here.9858/page-260#post-913737
https://www.xtremepapers.com/commun...st-your-doubts-here.9858/page-260#post-913752
https://www.xtremepapers.com/commun...st-your-doubts-here.9858/page-260#post-913784

^ AS paper 1 Notes by My Name read full posts and note down the mistakes!

https://www.xtremepapers.com/commun...st-your-doubts-here.9858/page-295#post-943761
^ The file attached here also.I did not make those notes,found them from a website.

 

[My Name]

guys any last minutes tips plz

Read questions carefully.
Since we do have enough time be sure to check the answers.
Solve each question pretending it is a new one no matter how familiar it seems.
Dont panic. XD

 

[The Godfather]

any idea what may come

 

[The Godfather]

 

[My Name]

Answer is D right?
It is a fixed expression that we use for net primary productivity.
NPP = GPP – respiration
Simple definitions..
NPP :Amount of energy made available by plants to animals, only at the herbivore level, and is expressed as kg/m2/yr.
GPP: The measure of all photosynthesis that occurs in an ecosystem.
So after reading the definition you know how you got the expression.
I hope that helps to make it clear.

 

[donewithtime80]

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_w12_qp_42.pdf

at 20°C difference due (only) to lack of (development of) motility (in mutants) / AW ; R ref to numbers of sperm
at 25°C difference due to fewer sperm(atids) and less (development of) motility

Please explain why this answer?

 

[***amd***]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w14_qp_12.pdf
Q27 and Q31 ?

 

[phanttasy]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w14_qp_12.pdf
Q27 and Q31 ?

27:
waterlogged soil -> lack of oxygen -> aerobic respiration decrease -> less ATP is synthesis -> less ions is actively transport into the the root hair cell -> root pressure decrease

30: D because the blood is moving from the left atrium(LA) to the right atrium(RA), the volume of blood of RA increase. Since pulmonary artery is connected to RA, so the blood pressure in pulmonary artery increase (more volume of blood in RA). On the other hand, LA has less volume of blood, so the blood pressure in aorta decrease. The blood originally from the LA is oxygenated blood. So the % oxygenation of blood in pulmonary artery will increase (as oxygenated blood flows from LA to RA to pulmonary artery)

 

[***amd***]

27:
waterlogged soil -> lack of oxygen -> aerobic respiration decrease -> less ATP is synthesis -> less ions is actively transport into the the root hair cell -> root pressure decrease

30: D because the blood is moving from the left atrium(LA) to the right atrium(RA), the volume of blood of RA increase. Since pulmonary artery is connected to RA, so the blood pressure in pulmonary artery increase (more volume of blood in RA). On the other hand, LA has less volume of blood, so the blood pressure in aorta decrease. The blood originally from the LA is oxygenated blood. So the % oxygenation of blood in pulmonary artery will increase (as oxygenated blood flows from LA to RA to pulmonary artery)

Thanks

But for q30 whY can't we say that blood will move from RA to LA and every thing is the other way around?

 

[phanttasy]

Thanks

But for q30 whY can't we say that blood will move from RA to LA and every thing is the other way around?

according to the question, it says the blood usually moves from LA to RA
we can't go against the question

 

[nehaoscar]

9093 English AS
Any tips on how to write a commentary?
Like the layout and perhaps a list of features and effects to look for?
Can anyone provide me with sample commentaries if you have done in school? (preferably with marks)

Also tips on paper 1 and paper 2 as well to get an A
Thanks in advance

 

[Bhaijan]

Help i dont understand how to do this question. The answer is A, this questiion is from june 2008

 

[phanttasy]

Help i dont understand how to do this question. The answer is A, this questiion is from june 2008
View attachment 57735

There are cohesion force between water molecules and adhesion force between the water molecules and the wall of the xylem vessel. During the day, the rate of transpiration is high, more water is evaporate from the moist mesophyll cell wall. This set up a great water potential gradient between the mesophyll cell and the xylem vessel, so more water is drawn up by transpiration pull. So the water is transport faster up to the leaf, the cohesive tension force will increase. Imagine you are sucking an empty plastic bottle. the diamter of the bottle will decrease if we suck more air out.


Hope you understand it > < some please correct me if I have any mistake

 

[Akshajistari]

Hi, could someone direct me to pdf's for the new 2016 edition revision guides for Biology, Physics and Chemistry (A level please) ?

 

[My Name]

Hi, could someone direct me to pdf's for the new 2016 edition revision guides for Biology, Physics and Chemistry (A level please) ?

I don't think that complete books will be available online
If you like I can give a link to the previous revision guides.