The Effect of Temperature on Anaerobic Respiration of Yeast

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The Effect of Temperature on Anaerobic Respiration of Yeast

We wanted to find the effect of temperature on anaerobic respiration

of yeast. We investigated how a mixture of yeast, water, sugar, and

flour were affected.

Diagram

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Apparatus

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1g of yeast

0.5g of sugar

10g of flour

6 measuring cylinders - to put the sachets in and the 20cm3 of water

Measuring cylinders to measure the water

Thermometers - to keep the same temperature in the water baths

Water baths - at 20ºC, 30ºC, 40ºC, 50ºC, 60ºC

Hot air oven - at 70ºC

Beakers - to use to put the yeast mixture in the cylinders.

Method

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We set up the apparatus as shown, and placed 1g of yeast, 0.5g of

sugar, and 10g of flour each into the beakers. Then we added 20cm3 of

water, measured with a measuring cylinder, and stirred the mixture

until there were no bubbles left in it, and it was a smooth paste.

Then the volume of the dough in each was 25cm3 and we poured it into 6

measuring cylinders. Then we placed the 4 cylinders in 10ºC, 30ºC,

40ºC, 50ºC and 60ºC in water baths at those constant temperatures,

maintained with a thermometer. Then we left a cylinder at room

temperature (20ºC) and the last in a hot air oven at 70ºC. Every five

minutes we took a measurement of the volumes in each measuring

cylinder, and took a record of it. We repeated this two times.

Hypothesis

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I predict that the cylinders above 20ºC will increase in the volume of

the mixture, and that the yeast in the 70ºC hot air oven will

increase, but will then stop rising. When yeast respires

anaerobically, bu...

... middle of paper ...

...d.

I hav creatd another experiment which investigates the best

temperatures at which yeast enzymes work best at. I want to

investigate further into what exactly is the yeast enzymes' optimum

temperature, as it was 101cm3 at 50C, but as I mentioned before - the

dough was at unevern temperatures, as it was hard to control it

without the special abilities of laboratory machines. I know that the

optimum temperature is between 40C and 50C.

Method

We will mix 1g of yeast, 0.5g of sugar, and 10g of flour, each in 4

beakers with 20cm3 of water, which will be measured with a measuring

cylinder. Then we will pour it into measuring cylinders, but this time

using a measuring cylinder with a larger opening, to avoid spilling

the mixture around the edges of it. Then, the volumes in each of the 4

cylinders will be 25cm3

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