required practical 9

Question 1

what is the purpose of methylene blue?

Answer 1

it is a redox dye that acts as an alternate electron acceptor of the electrons transferred during ATP synthesis, it turns from blue to colourless to indicate the end point

Question 2

method

Answer 2

1. set up water bath at 35c
2. add 5cm3 of yeast and glucose to three test tubes and add them to the water bath for 10 minutes
3. add 2cm3 of methylene blue and start the timer, shake for 10 seconds and place back in water bath
4. record how long it takes solution to go from blue to colourless
5. repeat using different temperatures
6. find the mean for each temperature

Question 3

what is the equation for rate of respiration?

Answer 3

1/mean time

Question 4

why does the yeast solution need to be buffered?

Answer 4

to maintain a constant pH so the enzymes are functioning at the optimum

Question 5

what is the effect of temperature on respiration?

Answer 5

as temp increases, ROR increases because enzyme activity increases
beyond optimum, enzyme activity decreases beacuse they denature