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AQA Biology AS Level Unit 2 thread

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Original post by Anam
Basically at the arteriole end there is a high hydrostatic pressure this causes filtration of the blood plasma in the capillary, so the small molecules(amino acids, glucose, water) pass through the capillary wall. These form tissue fluid surrounding the body cells.


ah ok thanks that actually explains it :biggrin:
yeah lol to me they dont look AQA type but apparently they are
Original post by edward090
can someone confirm that these questions are specific to AQA BIOLOGY AS LEVEL http://sciencemathsmaster.weebly.com/pack.html and not for any other exam board.
lulz so scared of bio unit 2 incase it is not bio like bio 1, i swear that bio1 is a cookery subject XD XD XD
are you guys confident btw?
Original post by maggie43
yeah lol to me they dont look AQA type but apparently they are


what makes u say "apparently they are"???
SOMEBODY pls EXPLAIN THOSE UGLY GODFORSAKEN POTOMETERS
Original post by lunaa.lovegood
SOMEBODY pls EXPLAIN THOSE UGLY GODFORSAKEN POTOMETERS


all it is is an experiment to test the rate of water movement, you have a plant inserted into the apparatus, placed into a beaker of water, and you have a bubble, this bubble is the thing you measure, so lets say you leave the apparatus for 10 minutes, you measure the distance moved by the bubble and measure the time taken, but to measure the rate you need to find the diameter of the capillary tube, you have to keep the temp, humidity, air movement and light intensity the same otherwise you get other factors involved.

Now, the rate of water movement will not be measured accurately because of some reasons, firstly some water is produced in respiration, which will affect the rate of movement, some water is used in photosynthesis and some is used for support, also due to human error, the apparatus might not be sealed airtight, so you'll have some air getting into it affecting the bubble movement. you cut the shoot under water to prevent air entering and you but it at an angle to increase surface area.
Original post by edward090
what makes u say "apparently they are"???


because it says AQA lol:colondollar::colondollar:
Original post by edward090
what makes u say "apparently they are"???


They are
They've appeared on past papers prior 2009
That's why the font looks weird


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aaaahahhahahahahah
I am so screwed
I really ****ed up unit 1
and one of my bio teachers died in April and the other had to take over and rush teaching so all this stuff on tissue fluid and half the things ppl are saying I've never heard of 😩😩
trying to finish my notes and then do past papers but not sure if I'll have enough time because it's such a big unit
any recommendations for best plan of action ??? I don't want an A or anything haha I'm planning on dropping it, I'd like a C/D


Posted from TSR Mobile
Original post by faggstagram
aaaahahhahahahahah
I am so screwed
I really ****ed up unit 1
and one of my bio teachers died in April and the other had to take over and rush teaching so all this stuff on tissue fluid and half the things ppl are saying I've never heard of 😩😩
trying to finish my notes and then do past papers but not sure if I'll have enough time because it's such a big unit
any recommendations for best plan of action ??? I don't want an A or anything haha I'm planning on dropping it, I'd like a C/D


Posted from TSR Mobile


You're better off aiming high anyway, best thing to do is past papers, do them mark where you went wrong and read up on the areas and then repeat, also try memorising the mark scheme as it helps :smile:
Say I got an A in the EMPA, and an E in Unit 1, what would I have to get in Unit 2 to get a B?

Thanks, from a very worried person
Hi can somebody explain this question ImageUploadedByStudent Room1432731627.220836.jpg
Many thanks :smile: i dont get what it means by carbon 1/4, how do you no what to circle. Thanks :smile:


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Original post by Sexybadman
Hi can somebody explain this question ImageUploadedByStudent Room1432731627.220836.jpg
Many thanks :smile: i dont get what it means by carbon 1/4, how do you no what to circle. Thanks :smile:


Posted from TSR Mobile

to get cellulose, you need to get a lot of beta glucose molecules binding together, they do this via condensation reactions, in other words you lose a water molecule when they mind, so looking at that how can you get a water molecule out? you draw a circle around the OH of one glucose and the H of another and there you have it, H2O :smile:
can someone give me a description for random assortment and crossing over,cheers
Original post by lunaa.lovegood
SOMEBODY pls EXPLAIN THOSE UGLY GODFORSAKEN POTOMETERS


A potometer (sometimes known as a 'transpirometer') is a device used for measuring the rate of water uptake of a leafy shoot. The reasons for water uptake are for photosynthesis and transpiration.

Potometers are often difficult to set up, as measurement-altering air bubbles in the xylem of the plant or in the apparatus must be eliminated. Everything must be completely water tight so that no leakage of water occurs.

There are two main types of potometers used - the bubble potometer (as detailed below), and the mass potometer. The mass potometer consists of a plant with its root submerged in a beaker. This beaker is then placed on a digital balance; readings can be made to determine the amount of water lost by the plant. It is important to note that the mass potometer measures the water lost through transpiration of the plant and not the water taken up by the plant.
Original post by CMooreFalcons
Say I got an A in the EMPA, and an E in Unit 1, what would I have to get in Unit 2 to get a B?

Thanks, from a very worried person


I'd say a comfortable A (surely you couldn't have done that bad in unit 1?)
So what exactly do we have to know about classifying plants?
Original post by mck9777
So what exactly do we have to know about classifying plants?


the taxonomy/classification:
kingdom
phylum
class
order
family
genus
species
(remember this: King, Phillip, Came, Over, From, Germany, Swimming.)

also you need to know the binomial naming system= genus and species.

what the term hierarchy means.

how a phylogenic system differs to a simple hierarchy

teh principles in which biologists use to classify organisms into groups

cant think of anything else
hope this helped :smile:
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Avatar for hum1
hum1
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http://us23.chatzy.com/33143508669104

biology revision chat so we can test each other
someone wrote this really nice notes
http://www.thestudentroom.co.uk/showthread.php?t=2212505

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