Investigating Respiration Flashcards
1
Q
germinating peas experiment
A
- as the peas start to grow they respire, releasing heat
- the thermos flask is insulated, so heat is not transferred to the surroundings and we can measure the change in temperature
- we only see a temperature rise in thermos A, as the peas in thermos B are dead (they have been boiled)
- in both thermos flasks the peas are soaked in Milton solution (bleach)
- this kills any bacteria - bacteria would also respire so this would affect results
- we could also use gas delivery tubes to collect any gas produced
- the gas can then be bubbled through limewater - the gas from flask A only would turn the limewater cloudy - this shows that carbon dioxide is produced
2
Q
hydrogen carbonate indicator and insects experiment
A
- the indicator is red, but turns yellow when the carbon dioxide concentration increases
- carbon dioxide reacts with water to form a weak acid
3
Q
investigating anaerobic respiration in yeast
A
- this equipment can be used to investigate the effect of changing a single variable on the rate of anaerobic respiration in yeast
- dependent variable could be the time taken for the limewater to turn cloudy
- you could also connect the delivery tube to a gas syringe, to measure the volume of carbon dioxide produced
4
Q
what do you do when an examiner asks you to describe experimental data?
A
say what the results are
5
Q
what do you do when an examiner asks you to explain what the results are?
A
say why the results occur