AQA BIOL2 Biology Unit 2 Exam - 26th May 2011

We won't be asked to calcualate SD.

How do you know that?

Sorry, this question might have been posted before, but is this a morning or afternoon exam?

Guys, is the CGP enough for the Water Transport in Plant. Or am I gonna have to know it in more depth?

Afternoon

Guys, is the CGP enough for the Water Transport in Plant. Or am I gonna have to know it in more depth?

u tell me lol

tell me all you know about water transport and I will tell you if it is enough...

Well this is what's in the CGP guide:

The symplast pathway - goes through the living parts of the cells - the cytoplasm.
The cytoplasm of neighbouring cells connect through plasmodesmata. (small gapps in the cell walls).

The apoplast pathway - goes through the non living parts of the root - the cell walls.
The walls are very absorbet and water can simply diffuse through them, as well as passing through the spaces between them.

- When water in the apoplast pathway gets to the endodermis cells though, its path is blocked by a waxy strip in the cell walls, called the Casparian strip. Now the water has to take the synplast pathway.

- This is useful, because it means the water has to go through the cell membrane.
Cell membranes are able to control whether or not substances in water get through.

- One past this barrier, the water moves into the xylem.

Both pathways are used, but the main one is apoplast pathway because it provides the least resistance.

(I just want to know if this is enough for the symplast/apoplast crap.) Thanks.

Symplastic is osmosis, apoplastic is cohesion tension, and that's it I think

Do I need to know about active transport of salts...etc?

yeh definitely, but there's nothing to it, just, "endodermal cells have carrier proteins that actively transport mineral ions into the Xylem, thus reducing water potential in the Xylem below that of the endodermal cells, so water moves in by osmosis"

Oh ok thanks.

How many papers have you done so far?

I've probably done all of the ones available, but there are only, like......four or three.
I think I've ranged from C-B, but grade boundaries are low so maybe an A.
Wbu?