AQA Biology Unit 2 08/06/2010 AM

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In terms of tissue fluid- do we need to know about hydrostatic pressure and colloid osmotic pressure?
Or just the fact that at the arteriole end there is a higher pressure than that of the osmotic pressure drawing them in and therefore molecules move from the solution into the capillaries....
And the reverse for the venule end..

Reply 61

hey_its_nay

I_Need_To_Revise

everything you said but colloid osmotic pressure

Reply 62

samzurai

guys i think the last 2
5 marker questions will be

1.describe the different ways water move through the plant

2.explain how meiosis increases genetic variation

Reply 63

Tam_91

samzurai

guys i think the last 2
5 marker questions will be

1.describe the different ways water move through the plant

2.explain how meiosis increases genetic variation

Yeah possibly, so what would you say for them?

For the first one:
1) I'd explain briefly osmosis of water into roots, then apoplastic and symplastic pathways of water from root to xylem, then root pressure contributing to some water moving up, and then talking about transpiration pull. You think that's alright for the full 5 marks?

2) I'd explain independant segregation, then genetic recombination by crossing over, and then fusion of gametes at fertilisation causing more variation.

Oh btw what 6th form/college do you go in Ilford? I live very near Ilford (Gants Hill).

Reply 64

jack1865

samzurai

check at the past paper thread, 'hippysnake' uploaded the QP + MS for jan 2010,

and the jan 09 and jun 09 are on the website along with the specimen

Do you have a link for that please? i cant seem to find it :/

Reply 65

samzurai

Tam_91

yh that sounds perfect, but what is root pressure man? i forgot? is the water from the xylem --> mesophyll?

for question 2 should be full marks,
oo gants hill!,oh yh i go to scrappy tower hamlets college, (i have alot of friends there), hey man i'm 'planning' to do optometry !, didn't realise wow, it seems to be a rare choice :frown:

Reply 66

Tam_91

samzurai

Yeah and when the water moves into the xylem from the endodermal cell cos the mineral ions are moved into the xylem by active transport which lowers the water potential in the xylem so the water moves into the xylem by osmosis, and this carries on up the xylem into the mesophyll cells.
Oh cool I used to live in Tower Hamlets, near Whitechapel. Yeah optometry sure is rare choice since most people wanna do Dentistry or Medicine if they go into health-related sciences, but I guess that's good for us optom applicants as it means less competition lol.

Reply 67

samzurai

Tam_91

haha, amen to that no competition lol, anyway what college do you go to?
and towerhamlets yes i used to live there there but i moved recently to ilford :smile:

,
yh thanks for the root pressure stuff

and is city university any good for optometry?

Reply 68

Tam_91

samzurai

haha, amen to that no competition lol, anyway what college do you go to?
and towerhamlets yes i used to live there there but i moved recently to ilford :smile:

,
yh thanks for the root pressure stuff

and is city university any good for optometry?

No problem. :smile:

It's good that we're preparing to answer questions early on here, so when it comes to the exam if those questions come up, we can breeze throught it and save time.

I go to ilford county 6th form in barkingside, I'm glad it's study leave from now though lol, no more bloody school.

Yeah City is pretty decent for optometry, though the top ones usually mentioned are Cardiff, Aston and Manchester. There's only 8 uni's that do optometry but it doesn't really matter too much which university you do it as they all have similiar graduation and employment rates (above 80%) and their teaching is regulated by some optometry council.

Reply 69

username297381

someone summarise the casparian strip please...
Ok, so water is moving along the appoplastic pathway, then its blocked and pushed into the symplastic pathway by the strip, and then into the xylem?
What's the point in that? How does this regulate flow?

Reply 70

samzurai

M|chael

its forced into cytoplasm of the endodermal cells, because the only way in which water can move into the xylem is when it is in the cytoplasm of the endodermal cell. so it forces the water from the apoplastic pathway into the cytoplasm so it can be moved into the xylem, if it were to remain in the cell walls, then the casparian strip is waterproof this disables osmotic processes to take place so no water -> xyelem,

i hope i helped :smile:

Reply 71

samzurai

Tam_91

No problem. :smile:

i was about to apply to there :rolleyes:

, but i was too late lol
yh thanks for the tip man

Reply 72

User12399

I'm going to try and go through the text book this half term and thanks for all the info here guys.
I hate this paper. Come on I need that A!

Reply 73

username297163

Hmm i hope not much comes up about plants and movement in a plant, that and tissue fluid seems to be the only things i just cant get my head around!

Reply 74

INeedToRevise

samzurai

im looking at optometry too

entry requirements are so high though- same as dentistry :s-smilie:

oooh and in terms of plants gas exchange- do we need to know how the stomata open and close

Reply 75

Tam_91

If you need any help/advice when applying for optometry feel free to ask whenever.

I don't think you need to know details, just that the guard cells are the cells that control the opening and closing of stomata.

Reply 76

samzurai

I_Need_To_Revise

im looking at optometry too

entry requirements are so high though- same as dentistry :s-smilie:

oooh and in terms of plants gas exchange- do we need to know how the stomata open and close

yh they sure are,

yh you need to know the guard cells, open +close the stomota controlling the rate of gas exchange, and conversing H2O!,

Reply 77

samzurai

how is everyone preparing for the HSW questions?

Reply 78

Tam_91

samzurai

how is everyone preparing for the HSW questions?

I've been doing those HSW questions in green in that AQA Bio Nelson Thornes book and the examination-style questions have a lot of HSW questions too, so that's helped out aswell. What about you?