Biology P 34 ..here what i got ..

[ahmed abdulla]

so first question will be about YEAST .. you will make dilution of them using a long tube attached to syringe and most probably suck some liquid and pour distilled water ..
and then graph + microscope slide as usual ...
any one can add extra informations ?????????

 

[Ikram Khaliq]

where is everyone?

 

[Dania_Yz]

so first question will be about YEAST .. you will make dilution of them using a tube attached to syringe and most probably suck some liquid and pour distilled water ..
and then graph + microscope slide as usual ...
any one can add extra informations ?????????

What's the graph about,what verses what??

 

[ahmed abdulla]

What's the graph about,what verses what??

dont worry !
MOST likely .. table on first column will be on the x-axis ... plus ..dont forget to label +units ...
and USE more than half of ur graph .. by choosing big no.s

 

[Dania_Yz]

dont worry !
MOST likely .. table on first column will be on the x-axis ... plus ..dont forget to label +units ...
and USE more than half of ur graph .. by choosing big no.s

Oh thank you! I still couldn't understand how would we carry out serial dilution and I can't find any video explains that

 

[joanna omar]

That yeast exp needed a gas syringe ?

 

[Chucky]

Can anyone point out a question in past papers similar to the yeast question mentioned here?
Any yeast related question will help

 

[mrnt3250]

Oh thank you! I still couldn't understand how would we carry out serial dilution and I can't find any video explains that

There are two methods of serial dilution:

First one is that you use dynamic sources, meaning for example initially you have 20 cm3 of 1% sucrose conc., then you want to reduce the concentration by half in each successive dilution. So what you do is that in the second beaker, you add 10 cm3 of 1% solution and 10 cm3 of water, halving the concentration to 0.5%. Then using this second beaker as source, take 10 cm3 of solution in this beaker, and add it to a new beaker, and add 10cm3 water, so it again gets halved, 0.25%, on and on...

Second method is that in an experiment you're asked to investigate effect of concentration (of e.g. sucrose), and you're given at least 50 cm3 of 1% conc. sucrose. What you want to do is to use this source wisely so you have a range of 1% to 0% of sucrose.
So for that, you make a table, and depending on how many beakers they have provided (usually 5), you choose your dilutions.
Total volume must be kept constant (e.g. 20cm3), and so you start with 20cm3 of sucrose (1%), and no water, then dilute by e.g. 5cm3 sucrose 15cm3 water (0.25%), and finally 0 cm3 of sucrose and 20cm3 of water (0%).

 

[Dania_Yz]

There are two methods of serial dilution:

First one is that you use dynamic sources, meaning for example initially you have 20 cm3 of 1% sucrose conc., then you want to reduce the concentration by half in each successive dilution. So what you do is that in the second beaker, you add 10 cm3 of 1% solution and 10 cm3 of water, halving the concentration to 0.5%. Then using this second beaker as source, take 10 cm3 of solution in this beaker, and add it to a new beaker, and add 10cm3 water, so it again gets halved, 0.25%, on and on...

Second method is that in an experiment you're asked to investigate effect of concentration (of e.g. sucrose), and you're given at least 50 cm3 of 1% conc. sucrose. What you want to do is to use this source wisely so you have a range of 1% to 0% of sucrose.
So for that, you make a table, and depending on how many beakers they have provided (usually 5), you choose your dilutions.
Total volume must be kept constant (e.g. 20cm3), and so you start with 20cm3 of sucrose (1%), and no water, then dilute by e.g. 5cm3 sucrose 15cm3 water (0.25%), and finally 0 cm3 of sucrose and 20cm3 of water (0%).

Thank you soo much this really helps

 

[Chucky]

There are two methods of serial dilution:

First one is that you use dynamic sources, meaning for example initially you have 20 cm3 of 1% sucrose conc., then you want to reduce the concentration by half in each successive dilution. So what you do is that in the second beaker, you add 10 cm3 of 1% solution and 10 cm3 of water, halving the concentration to 0.5%. Then using this second beaker as source, take 10 cm3 of solution in this beaker, and add it to a new beaker, and add 10cm3 water, so it again gets halved, 0.25%, on and on...

Second method is that in an experiment you're asked to investigate effect of concentration (of e.g. sucrose), and you're given at least 50 cm3 of 1% conc. sucrose. What you want to do is to use this source wisely so you have a range of 1% to 0% of sucrose.
So for that, you make a table, and depending on how many beakers they have provided (usually 5), you choose your dilutions.
Total volume must be kept constant (e.g. 20cm3), and so you start with 20cm3 of sucrose (1%), and no water, then dilute by e.g. 5cm3 sucrose 15cm3 water (0.25%), and finally 0 cm3 of sucrose and 20cm3 of water (0%).

So this can be used for YEAST?

 

[Utkrist]

Is this practicals of M/J/2013 paper 34 biology??

 

[mrnt3250]

So this can be used for YEAST?

For anything .. cause as the water proportion increases, the concentration of solution decreases.

 

[mrnt3250]

Is this practicals of M/J/2013 paper 34 biology??

Yes

 

[Utkrist]

is there the solution of yeast or.....??

 

[Chucky]

I thought yeast was a suspension not a solution?
Maybe we'll get glucose solutions (different concentrations of which we prepare using serial dilution) and then we add a fixed volume of yeast suspension and leave it for a few minutes. then we carry out reducing sugar test and compare colours? or time taken?

 

[mrnt3250]

I thought yeast was a suspension not a solution?
Maybe we'll get glucose solutions (different concentrations of which we prepare using serial dilution) and then we add a fixed volume of yeast suspension and leave it for a few minutes. then we carry out reducing sugar test and compare colours? or time taken?

Most probably...

 

[mrnt3250]

Please keep posting info in this thread only, don't make 1000 of them.

 

[Utkrist]

is your exam tommorrow????

 

[mrnt3250]

is your exam tommorrow????

You wanna do the paper like this?
You asked first are you taking 34, I said yes, now you're saying is your exam tomorrow? :|

 

[Utkrist]

I asked to chucky!