respiration experiments Flashcards
how can aerobic respiration is yeast be measured
using methylene blue, which changes from blue to colourless as it is reduced during oxidative phosphorylation
what are the key stages for measuring aerobic respiration with methylene blue
add yeast suspension and a substrate solution to a test tube
place the test tube in a 25 water bath for 10 mins to stabilise substrate
add methylene blue and seal tube
shake test tube for a few seconds then return to water bath
record time it takes for methylene blue to turn colourless
how do you calculate the mean rate of respiration using methylene blue
1 / mean time for colour change
why is it important to repeat this experiment
ensure accuracy and reliability
how is anaerobic respiration in yeast measured
using a gas syringe to measure CO2 produced
what are the steps for measuring anaerobic respiration in yeast
add yeast suspension and a substrate solution to a test tube
place the test tube in a 25 water bath for 10 mins to stabilise substrate
add liquid paraffin to cover solution preventing oxygen entry
attach a gas syringe to the tube and start the stopwatch
record the volumes of gas in the syringe at regular intervals
what does a respirometer measure
the rate of respiration by measuring oxygen consumption over time
how is the rate of respiration calculated using a respirometer
potassium hydroxide absorbs CO2 leaving only oxygen changes to be measured
as oxygen is consumed, the pressure in the tube decreases moving liquid in the capillary tube
how do you calculate vol of O2 using a respirometer
distance moved by liquid x diameter of capillary tube
what variables can affect respirometer results
temperature
substrate conc
use of potassium hydroxide
