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Fementation problem

Hi im gonna do a cwk expt next week about yeast respiration using changing concentration of glucose and frcutose.

im wonderin using changing concentrations of glucose and fructose, does that keep the independant varilbe constant?

also what concentration of glucose and fructose should i use? and yeast concentration? because if i have too high concentration of glucose active tranpsort wont take place? does active transport occur or osmosis here? im confused over that.

Thanks

Reply 1

JayEm

You've got 2 variables there, the type of sugar and the concentration. Just pick one sugar and vary the concentration of it.

Reply 2

alispam

Or do what i did and vary the types of sugar eg. do glucose, fructose and lactose - that quite interesting...

Reply 3

JayEm

alispam

Or do what i did and vary the types of sugar eg. do glucose, fructose and lactose - that quite interesting...

Yeah, but you need to be able to plot a graph of some results which you can write about in your analysis. By changing the concentrations you might get a straight line or curve which will give you some kind of relationship between conc. and fermentation rate or whatever you're investigating.

Reply 4

alispam

is it a requirement in your syllabus to plot a graph??? we didn't have to...
we analysed the reasons why some sugars led to faster rates of respiration than others.

Reply 5

Akthar

I can do this right, expt chnage glucose concentration, expt chnage fructose concentrations and then compare how they respire?

Also im confused how do yeast use the glucose? do glucose get trasnfered into the yeast by active transport? but if there were higher cocnetration of the sugar compared to yeast would the sugar go thru the cell membrane by diffusion?

Reply 6

JayEm

What exactly are you investigating? In fermentation, the yeast acts as an enzyme to catalyse the reaction. You could ferment the sugar without yeast just by leaving it in warm water I think, but this would take a long time.

Reply 7

alispam

i think their talking about anaerobic respiration rates in yeast (that is basically fermentation)

Reply 8

Akthar

yea its anaerobic respiration so im wondering what the yeast does with the glucose and what would happen with higher concentration of yeast compared to glucose? im going to use 15% yeast and 1,2,3,4,5 percent concentrations of glucose and fructose

Reply 9

alispam

its glycolysis - look it up on google...

Reply 10

Akthar

yea ok, but does glycolysis occur in anaerobic respiration?

and also, does glucose go into yeast cells by active transport by channel proteins? Im confused on these 2 bits. thanks

Reply 11

alispam

yes glycolysis always occurs whether in anaerobic or aerobic respiration.
glucose is polar and so must move through protein channels through the membrane.