RP 8 DCPIP

Question 1

Explain why it’s important water potentials are the same

Answer 1

To prevent osmosis occurring.

So chloroplast don’t swell and burst

Question 2

Why was test tube 1 set up.

Contained no chloroplasts and solution was in light.

Answer 2

1. Shows light does not impact DCPIP as no colour change.

2. To show chloroplasts are required

Question 3

Explain results in tube 3

It containing chloroplasts and solution was in light .

DCPIP turned colourless after 30 mins.

Answer 3

It shows DICPIP has been reduced by electrons from the chlorophyll

Question 4

Explain advantage of using the IC50 in this investigation

Answer 4

Acts as a standard point allowing for comparison of different chemicals

Question 5

Explain how chemicals which inhibit decolorisation of DCPIP could slow the growth of weeds

Answer 5

Less ATP produced

Less reduced NADP produced

Less GP converted into TP