Enzymes and pH: Lab Work

Our Biology teacher, Magdalena Ravagnan, proposed an experiment in which we would have a look in how the pH affected the shape of the enzymes and how much they changed it. This is the task.

Many plant tissues change colour when exposed to the air. The enzymes that produce the coloured products may be affected by pH.

Aim: investigate the effect of pH on the production of these coloured products formed on the freshly cut surface of a plant tissue

First we had to cut 2 pieces of banana of 1cm wide. We had to leave one exposed to the air and the other one in a petri dish and covered with orange juice and leave them for half an hour.

After half an hour…

Colour of exposed surface: darker

Colour of surface covered with orange juice: same initial color

The piece of banana in the orange juice with acidic Ph, didn’t let the colour enzymes work and so it stayed the same.The high acidic Ph that in the orange juice produced a change in the active site and so the substrate didn’t fit anymore.


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