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OCR A2 Biology planning exercise!

Just got my planning exercise and i dont know why the hell the question is talking about.Does anyone have any idea what the variable would be? does it have to do with the kidney?

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Reply 1

A Shining Light

What is the coursework question/title?

Reply 2

Lalli

YOU ARE REQUIRED TO PLAN AN INVESTIGATION TO DETERMINE THE CONCENTRATION OF ASPRINE IN URINE IN ORDER TO ESTIMATE THE AMOUNT LEFT IN THE HUMAN BODY

your planning must be based on the assumption that you have:
a 1.5% soln of asprin
a 1% soln of Iron III Chloride
school or lab resources

Reply 3

linksys

hello ive written about aspirin and its effects on pain relief(by inhibiting the enzyme cyclooxygenase)and its ability to reduce clotting.does any one know what to write about the kidney and aspirin i know its something to with it being filtered but thats about it!lol

Reply 4

Lalli

^^how can i start it off am a lil confused as to what the clotting has to do wiv the amount left in the body

Reply 5

Jenski

It doesn't. Its just something to put in the introduction to show that you can link areas of biology :smile:

Reply 6

Lalli

goes to show how dumb i am then lol

Reply 7

parag

I went on about ligand exchange between H2O and salicylate at first, then realised it had to be biological :redface:

Now I'm just going on about how it's absorbed, hydrolysed, metabolised and then how it goes through the kidney. I might do a bit on it's action too, not sure.

Reply 8

Lalli

^^would you put that in the prediction bit where you explain your prediction

it's a silly excercise isn't it???

Reply 11

Tgirl

I think we have different concentrations of Aspirin. so, probably aspirin will be the variable. my teacher was suggestin a calibration curve. but have not gone into details yet with us. does anyone have any idea what the prediction would be?
and how to estimate the amount of aspirin left?

Reply 12

Lalli

^^soemthing to do with using a colorimeter?

Reply 13

coldfusion

I need to check this but how do u plan to test for the amount remaining?

Reply 14

Tgirl

yes. the calorimeter will determine the colour of iron. i think!
any ideas about a clibration curve and what the results will be?

Reply 15

parag

Yea I've decided to use known concs of aspirin and use a colorimeter to get a calibration curve and then use that to calculate aspirin in the urine. The problem is, we've never used colorimeters before and google hasn't been amazingly helpful on the subject either. My biology teacher said he wasn't sure if it was school/college apparatus (we haven't got one) but it makes the most sense to use one. My major beef though is with how on earth you're meant to use aspirin in urine to work out what's left in the body, as I've discovered that most the aspirin you take gets metabolised to things that don't give the violet complex with iron (III) :confused:

Reply 16

Uhna

Bit of a stupid question but whats all the headings/sections we need to use?
I'm not sure where to start never mind everything else! = S

Reply 17

parag

I'm just following the same format as I did last year which was:

Introduction
Hypothesis
Preliminary Work & decisions
Variables & control
Method
Results
Analysis
Safety
Bibliography

Hope that helps :smile:

Reply 18

Tgirl

In place of a colrimeter, a spectrophotometer could be used. i am doing exactly the same, by having different conc of Aspirin. do we have to measure pH?
this planning exercise is horrible

Reply 19

parag

I've gotten around the pH thing by using the same sample of urine and I don't think pH affects Aspirin solutions, only the rate of excretion in the urine. Hopefully it should be alright, but it's just an educated guess.