A level Biology: Post your doubts here!

[Noor]

Does anyone happen to have old Biology AS past papers? By old, I mean 90's and maybe 80's if possible. Anyone? /:

 

[Student12]

Can anyone tell me the factors ehich influence the rate of leaf decomposition ??
and during months with higher than average temp. decomposition happens more rapidly- why ?

A biological term for the biomass of a feeding level at a particular moment in time ??
& What type of biome is most productive?

 

[Mubasher96]

What is the difference between qualitative, quantitative, semi-qualitative, and semi-quantitative analysis? or what are the separately? their definitions?

 

[hassam]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_s11_qp_42.pdf
q4 a ii
why ms says that farmers must buy new seeds each year......i dont understand,.....cnt it work like this that they buy seeds for next five years simultaneously

 

[omg]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_w10_ms_41.pdf
q.9 asks for the behaviour of chromosomes during meiosis.
crossing ovr and chaismata formation occurs at prophase 1, ryt????????/?

 

[Beca1206]

Hello everyone,
I would like to know if anyone have any tips on doing biology practicals, specifically how to use the stage micrometer.
Any other advice would be nice too.
Thank you.
Beca

 

[confused123]

Hello everyone,
I would like to know if anyone have any tips on doing biology practicals, specifically how to use the stage micrometer.
Any other advice would be nice too.
Thank you.
Beca

watching through a eye piece graticule won't give any paralox error.
if you want to know dat how much does one eye piece graticule represents then simply divide the number of e.p.g divisions with micrometer divisions to find what 1 e.p.c division represents. then multiply it with the number of e.p.g divisions visible to find the field of view or the width of cell you want to know..

 

[imanmalik]

I need paper 3 notes. Microscope and the wet practice .

 

[imanmalik]

By microscope i mean, images of slides with labels highlighting tissues. and wet practical - tips

 

[imanmalik]

and what are the calculations behind serial dilution? just wanted to make sure

 

[confused123]

By microscope i mean, images of slides with labels highlighting tissues. and wet practical - tips

just type on wikipedia whichever slide image you wanna see..

 

[maleeha123]

plzz help me .......what are DNA probes??

 

[confused123]

plzz help me .......what are DNA probes??

sure but is this an as level question?

http://en.wikipedia.org/wiki/Hybridization_probe
http://www.ncbi.nlm.nih.gov/pubmed/1718662
http://medical-dictionary.thefreedictionary.com/DNA+probe

 

[omg]

pls smby check my qs too :/

 

[Nibz]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w10_ms_41.pdf
q.9 asks for the behaviour of chromosomes during meiosis.
crossing ovr and chaismata formation occurs at prophase 1, ryt????????/?

Yes. But their function is to help align the chromosomes on the metaphase plate which is during Metaphase I and so you'd have to describe that in Metaphase I. This is what the mark-scheme means, I guess.

 

[inkheart]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w10_ms_41.pdf
q.9 asks for the behaviour of chromosomes during meiosis.
crossing ovr and chaismata formation occurs at prophase 1, ryt????????/?

Early prophase 1...........and this chiasmata formation continues in metaphase I.......In anaphase 1 no chaismata mata formation............................ one good tip for you when bivalents are formed....chaismata formation occurs........so crossing over of genetic information occurs between non-sister chromatids.

 

[inkheart]

and what are the calculations behind serial dilution? just wanted to make sure

you can simply use ratio methods.......

 

[inkheart]

can somebody tell me about mode of action of antibiotics such as penicillin on bacteria?

 

[Gogo]

How can I make it easier to remember the stages of mitosis???

 

[omg]

Early prophase 1...........and this chiasmata formation continues in metaphase I.......In anaphase 1 no chaismata mata formation............................ one good tip for you when bivalents are formed....chaismata formation occurs........so crossing over of genetic information occurs between non-sister chromatids.

so it means we'll describe abt crossing over in metaphase nt prophase1?????