6 Yeast Complete

8/11/2019 6 Yeast Complete

1/4

Introduction

Succinic acid dehydrogenase is an enzyme that oxidise succinic acid (glycolysis) into fumaric acid as

part of the Krebs cycle. During the reaction the coenzyme FAD is reduced to FADH2. This reaction

represents a typical enzymatic reaction that involves a substrate (succinic acid), an enzyme (succinicacid dehydrogenase), and a product (fumaric acid).

While, we will use methylene blue an artificial hydrogen acceptor and as an indicator that this

reaction is taking place. a dark-green, crystalline compound, C 1 6 H 1 8 ClN 3 S, that dissolves in

water to form a deep-blue solution: used chiefly as a dye, as a bacteriological and biological stain,

and as an antidote for cyanide poisoning. Methylene blue will remove the electrons from FADH2 and

turn from blue to colourless. Thus we will able to determine the rate of the reaction by noting how

ling it takes the methylene blue to turn from blue to clear.

Methylene blue solution decolourised methylene blue solution

(Blue/ blue green) (white/ light blue)


2/4

Objectives

To differentiate the yeast respiration process at different situation.

Materials

Test tubes , 10 cm3 of yeast suspension , methylene blue solution , water bath , cork or rubber

stopper

Methodology

1. 3 test tubes are labelled with A B and C.

2.

Each tubesare filled with 10 cm3 of yeast suspension.3.

Tube C is boiled for 5 minutes.

4. Then, methylene blue solution is added by 10 drops into each test tubes.

5. All test tubes are heated in the water bath for 15 minutes with 38 celcius42 celcius.

6.

Then after 15 minutes, the colour changes in all tubes are observed

7.

Tube B is placed in boiling water for 5 minutes. Beware so that the tube is not shaked.

8. Tube A is plugged with cork or rubber stopper in order to shake the tube vigorously for more

or less 10 times. The colour changes is observed. The stopper at test tube A is removed and

place it into the water bath again.

9. Step 8 is repeated to tube B and tube C.

10.

The colour of suspension precipitated in each tubes are observed again.11.

The observations are recorded in the table.

RESULTS

Boiling tubes Colour of the suspension

After 15 minutes While shaking After shaking

A Light blue Blue green White

B Light blue Light blue Light blue

C Blue Blue Blue


3/4

DISCUSSION

Each test tubes contains yeast suspension was added with couple drop of Methylene blue solution

as an indicator to detect whether the respiration process of yeast take place or not.

After 15 minutes being heated in the water bath with 38C- 42C, there is two differentcolour of precipitated formed. Test tube A and B does formed light blue colour while test tube C

formed blue colour.

Test tube C formed blue colour because it was being boiled for 5 minutes before being

heated at 38C42 C with the other test tube. This caused the yeast cell to die because of the high

temperature. So, theres no respiration occur for Test tube C throughout the experiment and the

methylene blue colour remain unchanged.

For Test tube A and B, there is some respiration process of yeast occur as they are in a

favourable condition. This makes the colour of methylene blue changes. Even though theres a

respiration process occur but, it was very less respiration process take place within the cell for the

first 15 minutes resulting only light blue colour formed, and the methylene blue not fully

decolourised.

When all the test tubes being shaken, only test tube A change to blue green colour why the

others remain the same colour as before. Test tube B remains light blue colour because it was also

being boiled for 5 minutes after the 15 minutes heat up cause the yeast cell to die.

After the shaking and leaving for 15 minutes in the water bath, only test tube A changes to

white because theres respiration occur. This shows that yeast can only do the respiration at the

optimal temperature around 38C42 C and the cell will die if it being exposed at high

temperature.

CONCLUSION

The yeast is able to do respiration only in favourable condition such as in optimal temperature and

the cell will die if it is exposed to high temperature condition. So, the temperature of surrounding

affects the respiration process of yeast.


4/4

REFERENCE

1) http://www.csun.edu/scied/2-longitudinal/schuster/

2)

http://en.wikipedia.org/wiki/Yeast

3) http://www.youtube.com/watch?v=sbG6rpfy07Y

4)

http://www.slideshare.net/AldrinLozano/exercise-14-cellular-respiration-in-yeast

5)

http://www.reference.com/motif/science/respiration-of-yeast-experiments

6)

http://www.vernier.com/experiments/bwv/16a/effect_of_temperature_on_respiration/

7) http://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-

temperature-effects-respiration-in-yeast.html

8)

http://www.123helpme.com/view.asp?id=122462
http://www.csun.edu/scied/2-longitudinal/schuster/http://www.csun.edu/scied/2-longitudinal/schuster/http://en.wikipedia.org/wiki/Yeasthttp://en.wikipedia.org/wiki/Yeasthttp://www.youtube.com/watch?v=sbG6rpfy07Yhttp://www.youtube.com/watch?v=sbG6rpfy07Yhttp://www.slideshare.net/AldrinLozano/exercise-14-cellular-respiration-in-yeasthttp://www.slideshare.net/AldrinLozano/exercise-14-cellular-respiration-in-yeasthttp://www.reference.com/motif/science/respiration-of-yeast-experimentshttp://www.reference.com/motif/science/respiration-of-yeast-experimentshttp://www.vernier.com/experiments/bwv/16a/effect_of_temperature_on_respiration/http://www.vernier.com/experiments/bwv/16a/effect_of_temperature_on_respiration/http://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-temperature-effects-respiration-in-yeast.htmlhttp://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-temperature-effects-respiration-in-yeast.htmlhttp://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-temperature-effects-respiration-in-yeast.htmlhttp://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-temperature-effects-respiration-in-yeast.htmlhttp://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-temperature-effects-respiration-in-yeast.htmlhttp://www.123helpme.com/view.asp?id=122462http://www.123helpme.com/view.asp?id=122462http://www.123helpme.com/view.asp?id=122462http://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-temperature-effects-respiration-in-yeast.htmlhttp://www.markedbyteachers.com/as-and-a-level/science/experiment-to-show-how-temperature-effects-respiration-in-yeast.htmlhttp://www.vernier.com/experiments/bwv/16a/effect_of_temperature_on_respiration/http://www.reference.com/motif/science/respiration-of-yeast-experimentshttp://www.slideshare.net/AldrinLozano/exercise-14-cellular-respiration-in-yeasthttp://www.youtube.com/watch?v=sbG6rpfy07Yhttp://en.wikipedia.org/wiki/Yeasthttp://www.csun.edu/scied/2-longitudinal/schuster/

6 Yeast Complete

Documents

Transcript of 6 Yeast Complete