RP9-respiration in single celled organisms

Question 1

what is the function of the methylene blue dye in this practical

Answer 1

It is redox dye and acts as an alternate electron acceptor of the electrons transferred during ATP synthesis

Question 2

outline the procedure to measure the effect of temperature on the rate of respiration of yeast

Answer 2

-set up a water bath at 35C
-add equal volumes of yeast and glucose solution to three test tubes
-place test tubes in water bath and leave for 10 mins
-add 2cm3 of methylene blue to the test tubes and start the timer
-shake and then put back on the test tube rack and time how long it takes to turn colourless for each test tube
-repeat for temps at 40,50,60 and 70C

Question 3

why does yeast solution need to be buffered

Answer 3

-to maintain a constant pH so that enzymes function optimally

Question 4

what is the effect of temperature on the respiration of yeast

Answer 4

-as temperature increases, so does the rate of respiration as as the enzyme activity increases
-beyond the optimum, enzyme activity decreases due to denaturing of enzymes