A level Biology: Post your doubts here!

[Lola_sweet]

My conclusion is:

Trachea, bronchi, bronchioles, alveoli, all have elastic fibers.

As for alveolar duct... I think I'll go study other chapters now

hahahaha i will confirm this and i will let u knw

 

[My Name]

Ikr if only the book said something :/

IKR I scanned the whole chapter looking for Elastin fibres

 

[Lola_sweet]

IKR I scanned the whole chapter looking for Elastin fibres

revision guide only said abt alveoli

 

[princess Anu]

Actually you get to learn that in A2 syllabus. It is exocytosis, if you are going to consider Protein Synthesis. So after the whole process, the golgi apparatus starts pinching into shuttle vesicles that move on the cell surface membrane and fuse with and secrete the enzymes, proteins etc. So in this specific motion, those vesicles will be moving towards the CSM not the other way round. The question also mentioned 'concentrated', this probably means that when taking in large molecules, the conc is low and it starts building up at the RER... Besides, that co-transporter thing is sometimes known as Indirect Active transport. Moreover,after further research, Amino Acids are taken in by Endocytosis, Active transport(both forms), Facilitated diffusion. There isn't a specific way

yeahh but the question says " are introduced into a cell" doesn't that mean its actually ENDocytosis

 

[Mahmood Magdy]

yeahh but the question says " are introduced into a cell" doesn't that mean its actually ENDocytosis

Try checking the Examiner's report. I believe it will clear this confusion.

 

[malk mohamed]

any link for help in solving p4 bio the application part

 

[princess Anu]

why is C not the answer

 

[nehaoscar]

"Mass flow during translocation" refers to movement inside a phloem, not xylem. So it can't be C!

Oh Right!
But then i still don't understand how it affects the cohesion between water molecules... I mean that cohesion is a property of water... how will the fungi growing affect it... by making water less attracted to each other?... I thought it can affect adhesion but how cohesion?

 

[qwertypoiu]

Oh Right!
But then i still don't understand how it affects the cohesion between water molecules... I mean that cohesion is a property of water... how will the fungi growing affect it... by making water less attracted to each other?... I thought it can affect adhesion but how cohesion?

The fungi are growing in the xylem.
1) development of root pressure cannot be affected be this, since this is done in the roots by cells releasing ions, not xylem.
2) translocation cannot be affected, since this is about phloems.
3) uptake of water by root hair cells cannot be affected, since this happens in the root hair cells, not xylem
4) finally, cohesion is an essential property of water required for effective mass flow of water through the xylem, I'm not 100% sure how exactly the fungi may affect this, but presumably their growth there affects the water: perhaps water molecules are attracted to stuff in the fungi (maybe hydrophilic cell membrane)

 

[qwertypoiu]

bl

 

[fantastic girl]

Aoa guys
can someone give me a proper answer for Q1 c part ?
http://studentbounty.com/pastpapers...el/Biology (9700)/2012 Jun/9700_s12_qp_52.pdf

 

[Mahmood Magdy]

The fungi are growing in the xylem.
1) development of root pressure cannot be affected be this, since this is done in the roots by cells releasing ions, not xylem.
2) translocation cannot be affected, since this is about phloems.
3) uptake of water by root hair cells cannot be affected, since this happens in the root hair cells, not xylem
4) finally, cohesion is an essential property of water required for effective mass flow of water through the xylem, I'm not 100% sure how exactly the fungi may affect this, but presumably their growth there affects the water: perhaps water molecules are attracted to stuff in the fungi (maybe hydrophilic cell membrane)

Oh Right!
But then i still don't understand how it affects the cohesion between water molecules... I mean that cohesion is a property of water... how will the fungi growing affect it... by making water less attracted to each other?... I thought it can affect adhesion but how cohesion?

Guys try checking Nov 2004 P1 Q 30, it is the same question but the answer is ' conduction in the apoplast'
Conduction in the apoplast depends upon the cohesive forces, and therefore I think that qwertypoiu is right, maybe it attracts water towards it or something like that.

 

[Mahmood Magdy]

Guys I need help with nov 2003 p1 bio Q25 and june 2008 q27 P1 . They are both the same question but both have different answers. How is that ? :O :O

 

[salma_69]

Guys I need help with nov 2003 p1 bio Q25 and june 2008 q27 P1 . They are both the same question but both have different answers. How is that ? :O :O

they are not the same one is about solute potential and one is about solute concentration
this makes the 2 questions different as solute potential is the opposite of solute concentration

 

[qwertypoiu]

Guys I need help with nov 2003 p1 bio Q25 and june 2008 q27 P1 . They are both the same question but both have different answers. How is that ? :O :O

Thanks

 

[ashcull14]

please explain ?????

 

[qwertypoiu]

View attachment 52471
please explain ?????

is it A?

 

[qwertypoiu]

Guys try checking Nov 2004 P1 Q 30, it is the same question but the answer is ' conduction in the apoplast'
Conduction in the apoplast depends upon the cohesive forces, and therefore I think that qwertypoiu is right, maybe it attracts water towards it or something like that.

Wow sorry I meant to say thanks for this lol

 

[ashcull14]

is it A?

no its C plz can u help ?

 

[fantastic girl]

View attachment 52471
please explain ?????

multiply the given values
they hve given energy value for per unit mass so u multiply wid the total biomass
for eg :
R- 1x0.1 =0.1
0.1 is for one individual nd the total individuals in R is 10 000
so 0.1x10000 =1000
S- 100
T- 1.8
U- 450000
So the order is U-R-S-T
hope u got it!