Role of hydrogen acceptors.

Question 1

What is the process called in which hydrogen atoms are removed from molecules?

Answer 1

Dehydrogenase enzymes catalyse the reactions in reactions called dehydrogenation.

Question 2

How do redox indicators work?

Answer 2

The are a different colour when they are reduced as to when they are oxidised. They collect the hydrogen instead of the NAD and FAD and so show that respiration is occurring.

Question 3

State 3 redox indicators.

Answer 3

Methylene blue
Triphenyl Tetrazolium Chloride (TTC)
DCPIP

Question 4

Give the colour change for each.

Answer 4

Methylene blue - Blue to Colourless
TTC - Colourless to Pink
DCPIP - Blue to Colourless

Question 5

Give practical details on how to carry out this experiment.

Answer 5

1) Crush soaked peas to a paste in a pestle and mortar and place in a boiling tube.
2) Repeat with boiled peas
3) Make up some methylene blue of a suitable concentration
4) Add 2cm³ of methylene blue to each boiling tube and place in a water bath at 35ºC.
5) Observe the colour change over time.

Question 6

What are various experiments Redox indicators can be used for?

Answer 6

1) The example above
2) The effect of dehydrogenase activity on adding an intermediate of the krebs cycle e.g. succinate
3) Effect of malonate - competitive inhibitor of succinate dehydrogenase