IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: Dania on September 19, 2010, 04:20:25 pm

Title: CIE Biology Paper 3 - Practical Skills
Post by: Dania on September 19, 2010, 04:20:25 pm

Does anyone know a link where I can get more info on how to accurately calibrate an eyepiece graticule using a stage micrometer? Also, on how to draw plan diagrams precisely.

Title: Re: CIE Biology Paper 3 - Practical Skills
Post by: Deadly_king on September 26, 2010, 10:46:29 am

Quote from: Danii on September 19, 2010, 04:20:25 pm

Does anyone know a link where I can get more info on how to accurately calibrate an eyepiece graticule using a stage micrometer? Also, on how to draw plan diagrams precisely.

Sorry for the late reply.

Actually i had never visited such a site earlier. So i had to look for one which may help you.

Here is what you need :
http://www.microbiologyprocedure.com/microscopy-methods-in-microbiology/measurement-by-eyepiece-graticule.html

http://www.emsdiasum.com/microscopy/products/magnifier/stage.aspx

For biology practicals, this might help :
http://www.practicalbiology.org/

http://www.internet4classrooms.com/gateway_biology.htm

Unfortunately I could not get any links for the plan diagrams :(
I would be glad to help you with that if you want........let me know which parts you don't understand :)

Title: Re: CIE Biology Paper 3 - Practical Skills
Post by: Dania on September 26, 2010, 12:52:14 pm

Thanks.

I'll let you know about the plan diagrams, once I go through a past paper and have a doubt.

Title: Re: CIE Biology Paper 3 - Practical Skills
Post by: Dania on September 26, 2010, 06:50:52 pm

Anything on clonal proliferation? Or clonal selection? [ I think they're one in the same thing]

Title: Re: CIE Biology Paper 3 - Practical Skills
Post by: Deadly_king on September 27, 2010, 05:52:13 am

Quote

During antigen presentation the macrophage selects T-helper cells and B-cells that have membrane receptors that are complementary in shape to the antigens exposed.  This is known as clonal selection.

Clonal proliferation is described in the picture attached.

So they are not really the same thing. Clonal selection occurs first. Then the selected cell undergo clone proliferation (growth) by mitosis.

Here is a link which might be helpful : http://www.biologymad.com/

Go through its AS section and then ----> Immunology

Title: Re: CIE Biology Paper 3 - Practical Skills
Post by: Dania on September 30, 2010, 01:19:10 pm

I know that site. Thanks :)

Title: Re: CIE Biology Paper 3 - Practical Skills
Post by: Deadly_king on October 01, 2010, 07:14:28 am

Quote from: Danii on September 30, 2010, 01:19:10 pm

I know that site. Thanks :)

Anytime :)