Effect of Temp on Yeast Cells

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Bio coursework

Methylene blue

Yeast cells – explanation of respiration hence colour change etc

Low temp colour change should be visible as the yeast cells are not necessarily dead, just inactive.

Activity increases from 20-45 c

High rate around 30-40

Starts to slow down – basically enzyme curve see bio 1

100 degrees will kill all cells

Do a few preliminary keep working down until first blue solution appears in unit of ten Then work to find degree. If more accuracy then half a degree.

Show method to do this. Waterbath etc

Methylene blue

It can also be used as an indicator to determine if a cell such as yeast is alive or not. The blue indicator turns colourless in the presence of active enzymes, thus indicating living cells

A simple table with the temperature in one column and whether or not the cells survived

pick a high temp, then a low temp, then pick a point in between and iterate.

ten test tubes each in a water bath with 10 degree intervals should give you a rough idea, then once you have the test tube with the highest temperature that's still colourless (the methylene blue indicator) you can heat it up one degree at a time and find the exact temperature that kills the yeast cells

To multiply and grow, all yeast needs is the right environment, which includes moisture, food (in the form of sugar or starch) and a warm, nurturing temperature (70° to 85°F is best).


As a living organism yeast needs sugars, water and warmth to stay alive. which ferments the sugar in cereal (saccharo-mucus cerevisiae) to produce alcohol and carbon dioxide'

Baker's yeast is produced from the genus and species of yeast called Saccharomyces cerevisiae. The scientific name of the genus of baker's yeast, Saccharomyces, refers to "saccharo" meaning sugar and "myces" meaning fungus

The typical yeast cell is approximately equal in size to a human red blood cell and is spherical to ellipsoidal in shape. Because of its small size,...
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