AS LEVEL BIOLOGY... discuss here AS students only :)

[HubbaBubba]

Can somebody explain the bohr effect in a simple way?

 

[deane26]

That's in AS?? :| use other terms please maybe i didn't get what is it about

Sorry. I mean how function of B-lymphocytes(humoral/antibody) differ to that of T-lymphocytes (cell mediated response)

 

[mariyam95]

Guys could you help me what happens during closing of stoma in reference to the K+ ion and water potential. Thanks.

atp-powered proton pumps actively transport H+ ions outside the cell this creates a nagtive charge in the guard cells causing K+ channels to open n K+ IONS diffuse into the guard cells down an electrochemical gradient>
the high concentration of K+ ion lowers water potential inside the guard cells
so water moves into guard cells down a potential gradient. the entry of water increase the volume of guard cells so the expand and curve apart opening stomata

 

[deane26]

Can somebody explain the bohr effect in a simple way?

High conc of CO2 means there is high H+ conc therefore lower affinity of oxygen.

 

[NouranAyman]

Sorry. I mean how function of B-lymphocytes(humoral/antibody) differ to that of T-lymphocytes (cell mediated response)

When a pathogen enters the body the microphage cuts it open exposing its antigen, when antigen is exposed that attracts T cells and B cells. T helper cells having a complimentary receptor to the antigen receptor will bind to it and then divide by mitosis producing other T helper cells that respond by releasing chemicals cytokines that stimulate B cells and other T memory cells. Stimulated B cells will have antibody receptors on their cell surface membrane the one having a complimentary receptor to that of the antigen will divide by mitosis producing B plasma cells and B memory cells, B plasma cells will release their antibodies from their cell surface membrane and antibodies will get rid of the antigen by any way from their ways of functioning like agglutination , antitoxins etc... and memory cells will remain for a secondary immune respone

 

[NouranAyman]

i meant other T memory cells are produced not stimulated sorry

 

[mariyam95]

heyy guys can anyone explain facillitated diffusion to me like rEALLL good/??

facilitated diffusion... the movement of larg polar molecules from regions of their high concentartion to regions of their lower concentartion via special protien channels on the cell surface membrane.... thats it

 

[Irfan1995]

ok people confusion here : wat makes the cholestrol able to make the plasma memberane fluid?? is it the double bonds?

I don't really know how much you're supposed to know for the AS level. Our school offered an AP course last year, and here's what we took (I'll try to explain it as simply as possible).
Cholesterol has a hydroxyl- group (-OH) which is hydrophilic, so this part interacts with the phospholipid heads.
Also, cholesterol has four (hydrophobic) "cyclic" groups. This greatly increases the strength of the instantaneous dipole - induced dipole forces (the forces that hold molecules together). Since the molecules are more tightly bound, the membrane is more tightly packed, so this reduces the fluidity of the membrane.

Since cholesterol has both a hydrophobic group and a hydrophilic group, it can embed itself easily in the phospholipid bilayer.

 

[ruler_of_the_world]

Btw guys mutualism where one organism is supported by another in exchange for something is called symbiosis. Jus telling u guys in case this word is used

 

[daredevil]

heyy guys
can anyone explain to me all there is to know about water potential, pressure potential and solute potential?
there were some graphs my teacher told us to make and all but i learned nill from them so it would be great if u can help with it =) thankss

 

[Moi]

That's in AS?? :| use other terms please maybe i didn't get what is it about

Guys. Could someone explain me humoral and cell mediated response?? TQ

Humoral immuno responce: Secretion of specific antibodies by plasma cell in responce to the precence of antigens or stimulated helper T-Cells.

Cell-Mediated Responce: the responce of activated T-Cells to the presence od antigens . they recognise antigens . bind to them and destroy them.

 

[Moi]

atp-powered proton pumps actively transport H+ ions outside the cell this creates a nagtive charge in the guard cells causing K+ channels to open n K+ IONS diffuse into the guard cells down an electrochemical gradient>
the high concentration of K+ ion lowers water potential inside the guard cells
so water moves into guard cells down a potential gradient. the entry of water increase the volume of guard cells so the expand and curve apart opening stomata

this is not in the syllabus! right? it doesnt say anything abt the mechanism of opening and closing the stomata...

 

[Ahmed Khalel]

he guys,
which has a higher resolution 200nm or 20nm

 

[mariyam95]

this is not in the syllabus! right? it doesnt say anything abt the mechanism of opening and closing the stomata...

it is in the syllabus of A2 but its always good to know more so u can understand better

 

[mariyam95]

r

he guys,
which has a higher resolution 200nm or 20nm

resolution means how much a lens can distinguish between two different structures lying next to each other
i.e resolution of 200nm mean the lense can distinguish between two structure with 200nm space between them
n 20nm means the lense can distinguish between two structure with 20nm space between them
so 20nm is higher and better resolution

 

[MÁťT PŭמҚ]

hey, can sm1
Define globular protien.. more clearly..!!

 

[ruler_of_the_world]

he guys,
which has a higher resolution 200nm or 20nm

20 nm bc 200nm= 2*10^-7 m n 20nm= 2*10^-8 m
So greater the value in negative higher is the resolution.

 

[mariyam95]

20 nm bc 200nm= 2*10^-7 m n 20nm= 2*10^-8 m
So greater the value in negative higher is the resolution.

O.O NEVER SAW SUCH A THING ?!

 

[Irfan1995]

hey, can sm1
Define globular protien.. more clearly..!!

From the word 'globular', it's a protein that folds into a 'globe'-like shape. So instead of being flat, it is folded into a 3-D shape.

 

[MÁťT PŭמҚ]

y is transpiration is an inevitable consequence of gas exchange??



and outline the roles of phospholipids.cholestrol.glycolipids,protien andd glycoprotiens