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Effect of calcium ions on rate of reaction.

hey, this is for my biology planning exercise. Rennin is effected by the concentration of calcium ions, the higher the concentration, the faster the rate of reaction. i am struggling to understand in scientific terms, how he calcium actually affects the enzyme and makes it work quicker. there is not much on the internet about it so i would be grateful if anyone could give me some help.. cheers x

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Reply 1
I am stuck on that bit too. i have in my notes that it isn't the calcium that reacts with the rennin but the rennin breaks down a protein and then the calcium reacts with the product of that reaction.
Reply 2
our teacher actually said you don't have to go into the detail of what the chemical reactions and mechanisms are just talk about the denaturing of enzymes and how this affects the rate of reaction

am stuck on the range of concentrations to use if any o u guys could help me plz wud be much appreciated

did u guys find any secondary sources to use if so where our college not doin any prelimininary work
Reply 3
i went for 0.25 mol to 1 mol and included a control with no calcium :biggrin: if that helps
Reply 4
thnx K-T
Reply 5
im finding it difficult to find background information too
at the moment im trying to find out about rennin and what it does
but do i just need to be more general as in what enzymes do?
Reply 6
about rennin i think your onli expected to talk about how it interferes with the proteins in milk resulting in coagualtion Hope that helps

but because it states calcium ions intefere with activity of rennin i would think we'd have to talk more bout that. but can't seem to find anythin that makes sense

and you kno for the hypothesis do increase in calcium ions comcentration cause a decrease or an increase in rate of coagulation????????
Reply 7
increase in the rate i think im going with the idea that its a cofactor
using no calcium as a control isnt the control as technically that would be a concentration of it
im using a control of no rennin and adding a mean concenration of the CaCl2
my teachers are being no help whatsoever though!!
Reply 8
if anyone needs help with this i have msn..
Reply 9
i have finished mine now and hope its ok...www.milk.co.uk was quite a good site
Reply 10
hi
im stuck on the same coursework anyone who can help me add me on msn mod edit: no emails
Reply 11
i had mine handed back to me today and was told i did really well like A/B standard :biggrin: has any one else handed their's in or need some more help?
Reply 12
well,
when you get given the plan, you can mess around with apparatus and chemicals in the lab and figure out concentrations to use.
im using 1cm3 rennin because that seems to work quite nicely :rolleyes:
although...
it probably dosent matter what vol. you use because rennin is the enzyme, and yeah i know incresing enzyme conc increases rate of reaction, so if you wanted to do the experiment quickly you would add quite a bit more of the rennin than i am, but we dont actlly have to do the experiment so... im thinking just use the same amount of rennin in each and the results you get will be proporitonal.
add the amount of sodium citrate you need to get rid of all the Ca ions in the milk
then add CaCl2 to the solution so you know what vol. of ions is in each.
the Ca ions are a cofactor, so they help the rennin in the coagulation of milk because as soon as you add this to a solution containing say 1cm3 Na citrate, 10cm3 milk and 1cm3 rennin, the milk coagulates..
so it dosent change the enzyme rennin for the worst, it appears to help it but i dont know how?
Burdett, you go to my school, hope you can now guess who i am. lol :smile:
hey i understand the science behind this experiment, but how are you actually planning to do it? Are you literally adding the substances onto a slide and watchin it or are you goin to dip a slide into a beaker of milk, renin and a concentration of calcium ions at certain time intervals?
Reply 14
Ghub

so it dosent change the enzyme rennin for the worst, it appears to help it but i dont know how?


the Ca ions are a cofactor activator for the rennin, so they "assist in forming the enzyme-substrate complex by moulding either the enzyme or substrate into a more suitable shape" (found in Biology for Advanced Level, 4th edition by Glenn and Susan Toole) in this case the enzyme rennin.
Reply 15
i was going to put the mixture into a petridish
and dip the slide in immidiately whilst starting a stop clock
then look at it under a microscope
though
tbh
the curd flecks are pretty visiable to the naked eye anyway
:biggrin:
Reply 16
there would be 6 dishes with 6 different mixtures containing differnt volumes of CaCl2.
and id just do them one after the other.
i dont really know how else to do it? what were you thinking of rachel_dingley?
Reply 17
hi! can i just check something... ok as you increase the concentration of calcium ions the coagulation time/rate decreases, and when you decreas concentration of calcium ions the coagulation time/rate increases?
PLEEEEASSSEEEE HELP!!!!
increase calcium ions time decreases and rate increases cos they're opposite arn't they i think tho dont trust me lol! Do we need to write about how they actually react in the theory side or not?
If calcium is a cofactor what is the substrate in the reaction? Please reply!