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AQA BIOL2~3rd June 2013~AS Biology (Now Closed)

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can somebody help!
"Why is it useful to calculate the index of diversity than record the number of species" -_-

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Reply 2841

anonymousecheese

HEPATIC VEIN-away from liver
HEPATIC ARTERY- to liver

HEPATIC PORTAL VEIN- away from gut to liver

RENAL VEIN-away from kidney
RENAL ARTERY-to kidney
:smile:

Reply 2842

Suzanna5678

Is it too early to go to bed

Reply 2843

annaelizabet

Would someone be happy to go over the ways in water transports in a plant? Like root pressure, etc. I HATE PLANTS :frown:

Reply 2844

anonymousecheese

Yaaaaaaaaaaaaaaaaaaay!!!!

Reply 2845

thechem1

Original post by PrimusInterPares

can someone explain how mutation in base sequence changes a protein to make it non functional???
thank you

-Mutation in DNA causes the amino acid sequence to be different

-Different amino acid sequence gives different tertiary shape of protein

-Different tertiary shape means different shaped active-site

-So substrate cannot bind and cannot form ES-complexes therefore the enzyme becomes non functional

Reply 2846

BioChemSocio

Original post by chelley2

can somebody help!
"Why is it useful to calculate the index of diversity than record the number of species" -_-

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To know the number of different species and number of individuals within a species as some species occur in small numbers

Reply 2847

username984585

Original post by chelley2

can somebody help!
"Why is it useful to calculate the index of diversity than record the number of species" -_-

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It shows the number of individuals in a species? :smile:

Reply 2848

SophieL1996

are there any past q's on fish apart from 09 jan?

Reply 2849

ajv1000

Original post by chelley2

can somebody help!
"Why is it useful to calculate the index of diversity than record the number of species" -_-

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shows no of individuals and no. of species

Reply 2850

Manni

Original post by Nav_Mallhi

HAHA! I love my languages, can speak 5 in total. :biggrin:

It was much much harder than any of the past papers, hopefully the grade boundaries should be low.

Mechanics or Stats?

Wow check you out! That's quite impressive

yeah I really do hope so!

stats wby

Reply 2851

anonymousecheese

Original post by annaelizabet

Anyone need help??????

YES PLEASE Q 4C on may 12

Reply 2852

KaranbirBandesha

Original post by chelley2

can somebody help!
"Why is it useful to calculate the index of diversity than record the number of species" -_-

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Index diversity takes into account each individual in each species and some species may have a small number of individuals

Reply 2853

Sorro10

Original post by annaelizabet

Would someone be happy to go over the ways in water transports in a plant? Like root pressure, etc. I HATE PLANTS :frown:

Basically water wants to get from the soil into the xylem vessels. It can do this by 2 methods or 'pathways' called the SYMPLAST PATHWAY or APOPLAST PATHWAY. (Might be useful if you get a labelled diagram showing xylem/root hair cell etc whilst reading this).

Symplast Pathway

In the Symplast pathway, water moves through the CYTOPLASMS of the cells.
Water diffuses along a water potential gradient through PORES between the cells of the Cortex called plasmodesmata. The Cortex is simply all the cells between the Root hair cell and the Xylem vessel.

Apoplast Pathway

In the Apoplast pathway, water moves through the CELL WALLS of the cells.
Water stops at the ENDODERMIS as there is a CASPARIAN STRIP which prevents the water from passing further, making the water pass through a membrane by osmosis down a water potential gradient INTO THE SYMPLAST PATHWAY, which is useful as it prevents harmful substances such as toxins or viruses from entering the xylem vessels as the membrane would not let them past.

--------------------------------------------------------------------

EXTRA

- Water potential in the root hair cell is lowered by the active transport of mineral ions from the soil, hence water can move from the soil into them down a water potential gradient.

Watch this, if you need more help:

http://www.youtube.com/watch?v=TWNtXw-MWtE

Reply 2854

thechem1

Anyone got a potential 6 marker on gas exchange in fish?

And a sample answer.

Reply 2855

annaelizabet

Original post by anonymousecheese

YES PLEASE Q 4C on may 12

is there anyway you could tell me it? I can't seem to find that paper :frown:

Reply 2856

Paulineuh

Is it possible to get full UMS without getting full marks?

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Reply 2857

_iiGEO

Original post by marseille_h

I converted the cm and the um into meter, (x10^-2cm) and (x10-6um) but when i measure from X to Y I get 2.2cm, am i measuring it wrong or my ruler is trolling me :biggrin:

.

(4.9 x 10^-2) / ( 20 x 10^-6) = x2450

so my units are right but my measurment of the image is not right..

i just measured it again you can get either 4.8 4.9 or 5.0cm i dont know how your getting 2.2cm, oh wait.. is the past paper printed out in the normal size or have you shrunk it down to smaller size? maybe that explains why the size of your image is small when you measure it.. let me know :biggrin:

but yeah all your other units are correct