A level Biology: Post your doubts here!

[DANGERBP]

hey ppl !!!! what do we need to know about myoglobin !!!! helpp !

 

[maybeitwasnoone]

The concentration of sucrose, where is it highest? Mesophyll cells or the Phloem? :/

 

[ismailmz]

@ DANGERBP : for myoglobin u just have to know that it collects oxygen and stores it. Myoglobin is in the muscle so it only releases oxygen when haemoglobin has low concentration of oxygen.

@maybeitwasnoone : I am not sure about the answer but as far as I know sucrose concentration is in phloem not in mesophyll cell. To be honest i actually forgot what role mesophyll cel plays

 

[maybeitwasnoone]

@maybeitwasnoone : I am not sure about the answer but as far as I know sucrose concentration is in phloem not in mesophyll cell. To be honest i actually forgot what role mesophyll cel plays

Mesophyll cells have chlorophyll in them, which means they photosynthesize thus producing glucose. It is from here that glucose diffuses as sucrose into the phloem. So all the while, when some is being transported by the phloem, don't you think the mesophyll will continue producing sugars?
Correct me if my reasoning is wrong. :/

 

[ismailmz]

Mesophyll cells have chlorophyll in them, which means they photosynthesize thus producing glucose. It is from here that glucose diffuses as sucrose into the phloem. So all the while, when some is being transported by the phloem, don't you think the mesophyll will continue producing sugars?
Correct me if my reasoning is wrong. :/

well i do remember some of it now, mesophyll cell is also responsible for transpiration, ie diffusion of water through it. As far as my knowledge is concerned companion cell is responsible for the transport of sucrose from root, by to the phloem where it moves by mass flow. So this makes it clear that the concentration of sucrose is more likely to be in the phloem than in mesophyll cell.
@maybeitwasnoone i dont if ur concept is correct but hats of, it was worth somthing tanx

 

[maybeitwasnoone]

well i do remember some of it now, mesophyll cell is also responsible for transpiration, ie diffusion of water through it. As far as my knowledge is concerned companion cell is responsible for the transport of sucrose from root, by to the phloem where it moves by mass flow. So this makes it clear that the concentration of sucrose is more likely to be in the phloem than in mesophyll cell.
@maybeitwasnoone i dont if ur concept is correct but hats of, it was worth somthing tanx

There were four choices as to where sucrose concentration was the highest. The most obvious two being the mesophyll cell and the phloem. A companion cell was drawn there, but it wasn't a choice. :/
I could link the November 2011 Paper 11 but it ain't here.

 

[ismailmz]

That would be great man

 

[maybeitwasnoone]

That would be great man

But it ain't since I got no paper.

Thanks for your help anyways

 

[Nibz]

Here you'll find all Oct/Nov 2011 papers: http://xtremepapers.com/community/t...apers-marking-schemes-examiner-reports.11543/
As for your question, in reality both cases are possible. But as far as AS-syllabus goes, remember that ' the concentration of sucrose is greater in the mesophyll cells where it is produced by photosynthesis than in the cells of phloem'

 

[ismailmz]

Here you'll find all Oct/Nov 2011 papers: http://xtremepapers.com/community/t...apers-marking-schemes-examiner-reports.11543/
As for your question, in reality both cases are possible. But as far as AS-syllabus goes, remember that ' the concentration of sucrose is greater in the mesophyll cells where it is produced by photosynthesis than in the cells of phloem'

man tanx alooot

 

[Nibz]

No problem :]

 

[maybeitwasnoone]

Here you'll find all Oct/Nov 2011 papers: http://xtremepapers.com/community/t...apers-marking-schemes-examiner-reports.11543/
As for your question, in reality both cases are possible. But as far as AS-syllabus goes, remember that ' the concentration of sucrose is greater in the mesophyll cells where it is produced by photosynthesis than in the cells of phloem'

Thanks loadz for the papers.

If that was so, why does the mark scheme contradict your answer?
Hahaha we can sue CIE now (Y)

 

[Nibz]

It must be the other way round then

 

[shyqueen]

plzzz anybody explain me da meaning ov da term independent variable n dependent variable???

 

[maybeitwasnoone]

Independant Variable is what YOU vary. It appears in the x-axis of the Cartesian plane.
The dependant variable is varied i.e is influenced and changes by what you've varied. It appears on the y-axis of the Cartesian plane.

 

[iceman]

hey everyone...what is the correct way to draw a plan diagram in our biology practical??? thanks in advance

 

[shyqueen]

Independant Variable is what YOU vary. It appears in the x-axis of the Cartesian plane.
The dependant variable is varied i.e is influenced and changes by what you've varied. It appears on the y-axis of the Cartesian plane.

thnkss alooot mate!

 

[maybeitwasnoone]

thnkss alooot mate!

Glad to be of help

 

[Gémeaux]

Q. 2, paper 1, may/june 2002. sorry cud not attach its link, even then if anyone cud help me with it.

 

[rz123]

Q. 2, paper 1, may/june 2002. sorry cud not attach its link, even then if anyone cud help me with it.

type the question as this ppr is not present in xtremepprz