Photosynthesis dehydrogenase practical Flashcards
What empty people of enzyme catalysés the reduction of NADP
A dehydrogenase enzyme
What is the colour change of DCPIP when it gets reduced
Blue -> colourless
How does DCPIP get reduced
Accepts electrons
What is measured for the rate of dehydrogenase enzyme
How quickly DCPIP decolourises
What instrument measures how much colour is left
A calorimeter
What is a light source in thus experiment
Lamp
How do you vary light intensity
The distance away from the lamp
Write method for dehydrogenase enzyme practical
- Cut leaves
- Use pestle and mortar to bring leaves with some chilled isolation solution
- Filter liquid into beaker using funnel lined with muslin cloth
- Transfer to centrifuge tubes
- Centrifuge at high speeds for 10 mins
- Chloroplasts will gather at bottom as pellet
- Remove supernatant
- Resuspend pellet in fresh chilled isolation solution
- Store in ice bath
- Set up calorimètre with red filter
- 0 calorimètre with distilled water
- Set up test tube rack with a certain distance away from the lamp
- Switch lamp on
- Add 2cm3 of DCPIP and 2cm3 of chloroplasts extract
- Mix
- immediately take out sample and put in calorimètre
- Repeat every 2 mins for 10 mins at different distances away from the lamp
What is chilled isolation solution
Sucrose
KCl
Phosphate buffer at ph7
What is produced with the chloroplasts pellet is resuspended in chilled isolation solution
Chloroplast extraction
What does it mean if the solution has a higher absorbance
It has more colour
What are the results of dehydrogenase is working at a fast rate
The absorbance will decrease
As the DCPIP is reduced and gets decolourised
What is the control in this experiment
Have 2 test tubes per distance away from the lamp
Both containing the same amount of chloroplast extraction and DCPIP
But one is in tin foil
So no light can be absorbed by it
Each control should be the same
