A level Biology: Post your doubts here!

[Alazne Diamond]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s13_qp_11.pdf

How to solve Q4

40 EPG=10 micro metres (0.1mm=10 micrometres)
so radius is (50x10)/40 = 12.5 micrometres

Area of a circle=pi x r x r
=pi x 12.5 x 12.5
= 490 micrometres
=4.9 x 10^2 micrometres

(someone explained before)

 

[Snowysangel]

infolded to allow expansion for increasing S.A not for gaseous exchange
yes to increase inflammation and make mast cells release histamine to attract nearby neutrophils.

Lol go over the questions again. A was that they're extensively folded to allow expansion....C was that they're folded to increase the SA. The answer was A....and in the second question, it said that histamine is released without antibody-antigen binding. See deep down we all know that these answers are damn weird

 

[sumeru]

what variant?

you gave 12?

 

[areebaization]

why is ATP needed in companion cells?

 

[daredevil]

why is ATP needed in companion cells?

bcz companion cells are there to provide energy for the seive tube cells.... ATP is a source of energy

 

[areebaization]

bcz companion cells are there to provide energy for the seive tube cells.... ATP is a source of energy

I know that
But precisely which step of translocation needs ATP?
1)for pumping H+ ions out of the seive tube (initial step of translocation) or
2)for loading of sucrose

 

[Karim Nabil]

Lol go over the questions again. A was that they're extensively folded to allow expansion....C was that they're folded to increase the SA. The answer was A....and in the second question, it said that histamine is released without antibody-antigen binding. See deep down we all know that these answers are damn weird

yes, anyways we have finished p1... so no need further explanations

 

[daredevil]

I know that
But precisely which step of translocation needs ATP?
1)for pumping H+ ions out of the seive tube (initial step of translocation) or
2)for loading of sucrose

i dont know about that.. but i think that it just is there to keep the seive tube celll alive.. and procide energy like respiration and stuff... do confirm from another source

 

[Karim Nabil]

I know that
But precisely which step of translocation needs ATP?
1)for pumping H+ ions out of the seive tube (initial step of translocation) or
2)for loading of sucrose

pumping H+ ions out of the companion cell*
and yes, these both needs ATP but priority goes first to H+ ions then sucrose molecules

 

[sumeru]

Who gave p12 today?

 

[EmiraS]

I know that
But precisely which step of translocation needs ATP?
1)for pumping H+ ions out of the seive tube (initial step of translocation) or
2)for loading of sucrose

1.
because its an active transport so it needs atp, its going up the concentration gradient i believe

 

[saaara]

Who gave p12 today?

Me

 

[NARIK SHAH]

Me

how was it ?

for me p 11 was a full crap

 

[sumeru]

Me

How was it?

 

[Snowysangel]

How was it?

How was yours? I've already gotten 5 answers wrong

 

[saaara]

how was it ?

for me p 11 was a full crap

P12 was full of crap too

 

[saaara]

How was it?

Honestly it was horrible how was it?

 

[sumeru]

I think, it went well

 

[saaara]

I think, it went well

No it didnt I hope we did well though but no.. some questions were kinda weird

 

[saaara]

Guys youre not allowed to discuss questions until 24 hours pass or youll be banned or disqualified