The effect of temperature on the survival of yeast cells

[funky pisces]

HEY BROADBELLY
THANKYOUUUU so much for all your help...i cn c wat i gta do nw for da prediciton n dat...

buh u knw ma results ye..u sed i should quote from ma own results...but da thing is i ent carrying out the experiment ...im just pallning it so lyk what shoudl i base ma conclusins on? should i just base it on a theory from a secondary source?

oh ye and bou ur calorimeter thing...i was told that we should do da calorimeter idea coz its too complicated...

funky pisces xxx

[broadbelly]

hey funk P,
ye i finkthe colorimter and the haemocytometer things are all 2 complicated, ironic cos i was the one who bummed n about the colorimter 4 quite a wile, but iv come 2 believe that ther not looking 4 anything complicated, it ses "shool lab" equip. so im just doing it by looking to see at which temperature it stays blue, which u cud argue is the best u can get for school lab equipment.

ye base em on a secondary source, and kinda on ur prediction aswell, so say in a table of temperatures and results, the lowest temperature which kills all of them mite be 60, so u say "solution is blue at 60, tehrefore this shows me that 0 is the lowest temperature which kills yeast cells/denatures enzymes" and maybe find sum site on teh internet wiv a temperature guide of yeast enzymes and compare it and say "this source supports my findings" that is if ther similar, and u may as well make em similar seen as tho u can.

ok? im luky ihav an inset 2day cos its i 4 2moro, im just guna spend teh whole da doin it
oh and hats off 2 rebecca i fink cos she started all this, good work

[emo-lady]

there isn't actually a word limit, you're advised to keep between 500 and 1000 because it stops you waffling on. they will still mark 20000 words but it helps if it's under 1000.

[Jacob]

I was told that they are very strict on word limits and will start to penalise you immediately after you go beyond 1000 words because they take away the mark(s) for structure of work.

[MIKKI020490]

does anyone know what the ph is that is needed for the buffer in the tempreture effecting enzymes planning exercise
please help

[broadbelly]

If u needd a pHbuffer i rekon theyd hav supplied one, its one of them lil extras which u cud get away wiv missing out aslong as u state why, cos lets face it, teh solutions are water based, all guna generally be neutral, plus if ther is a pH change then what happens for 1 will pob end up happening 4 all of them,
but it cud b i missed sumit major by not doing any pH bufer work, so hu knows

[CrimsonFalcon]

I was told that they are very strict on word limits and will start to penalise you immediately after you go beyond 1000 words because they take away the mark(s) for structure of work.

yeap. i heard that too. make sure you mark it correctly with the 200 word inteval at the margins, and dont go over 1k at all. ^_~

[Cazzii]

to people wanting to use the colourimeter, and the heactomadoodaa, u should do a preliminary experiment, cos its not necessary

[baby_jojo]

we were told that we had to find the hightest of the lowest
ie what is the highest temperature below the optimum temp. that denatures all the yeast enzymes!

[Ulbrid]

to people wanting to use the colourimeter, and the heactomadoodaa, u should do a preliminary experiment, cos its not necessary

I've done a preliminary experiment. How'd you suggest carrying out the investigation; simply eyeing the colour of the solution? Because, just because it looks blue, it doesn't meant that all of the yeast cells are dead.

[blcr11]

The eye is a pretty good comparator if you have decent references to compare against. What are you going to use as your reference for your colorimetric observations and what wavelength will you use? In other words, how will you know any better by colorimetry than you can by eye what "completely decolorized," "partly de-colorized", or "completely blue" represents? If you're thinking that the color of the cells will help, then I ask why you would want to use a colorimeter--the light scattering effects of the cells will make colorimetry difficult to do. The "blue"or "not blue" coloration of the cells looking through a microscope/hemocytometer won't tell you anything different than the coloration of the bulk solution, either. You're welcome to try colorimetry to determine your endpoints if you wish. I think you're making life difficult for yourself.

[Ulbrid]

The eye is a pretty good comparator if you have decent references to compare against. What are you going to use as your reference for your colorimetric observations and what wavelength will you use? In other words, how will you know any better by colorimetry than you can by eye what "completely decolorized," "partly de-colorized", or "completely blue" represents? If you're thinking that the color of the cells will help, then I ask why you would want to use a colorimeter--the light scattering effects of the cells will make colorimetry difficult to do. The "blue"or "not blue" coloration of the cells looking through a microscope/hemocytometer won't tell you anything different than the coloration of the bulk solution, either. You're welcome to try colorimetry to determine your endpoints if you wish. I think you're making life difficult for yourself.

It's difficulty shouldn't put anyone off, since we don't actually have to carry out the experiment. As for references, you can test 2 solutions in the colorimeter: 1 which contains all living yeast cells (i.e. only heated up to around 30 degrees Celsius) and 1 which only contains dead yeast cells (i.e. heated up beyond boiling point. Then you can calculate the percentage, relative to these references, of all of the in between experiments carried out.

Anyway, i still think using a haemocytometer is still the best method; you can actually calculate the ratio of living to dead yeast cells to find out, accurately, when they're all dead.