Anaerobic Respiration Flashcards
1
Q
What’s the experiment for anaerobic respiration
A
- Put a known volume and concentration of substrate solution in a test tube. Add a known volume of buffer solution to keep the pH constant
- Place the test tube in a water bath set to one of the temperatures been investigated. Leave it there for 10 minutes to allow the temperatures of the substrate to stabilise
- Add a known mass of dried yeast to the test tube and stir for two minutes
- After the yeast has dissolved into the substrate solution, trickle some liquid paraffin down the inside of the test tube so that it settled in and completely covers the surface of the solution. This will stop oxygen getting in, which will force the yeast to respire anaerobically
- Put a bung, with a tube attached to a gas syringe, in the top of the test tube. The gas syringe should be set to zero
- Start a stop watch as soon as the bung has been put in the test tube
- As the yeast respire, the co2 formed will travel up the tube and into the gas syringe, which is used to measure the volume of co2 released
- At regular time intervals, record the volume of co2 that is present in the gas syringe. Do this for a set time
- A control experiment should also be set up at each temperature, where no yeast is present. No co2 should be formed without the yeast
- Repeat the experiment 3 times at each temp you’re investigating. Use your data to calculate the mean and rate of co2 production
2
Q
How does pyruvate produce ethanol
A
The pyruvate molecule formed at the end of glycolysis loses a molecule of carbon dioxide and accept hydrogen from reduced NAD to produce ethanol
3
Q
How do we produce lactate from pyruvate
A
When oxygen is in short supply, NAD from glycolysis can accumulate and must be removed. To achieve this each pyruvate molecule produced takes up the two hydrogen atoms from the reduced NAD produced in glycolysis to form lactate
4
Q
How can lactate be oxidised back to pyruvate
A
Can be further oxidised to release energy or converted into glycogen
