dcpip is often used to measure the electron transport chain in plants. it has a higher redox potential (electron affinity) than the fe-s complex in cytochrome b and will therefore "steal" electrons from it. this means that cytochrome c does not receive them. the process cuts off the electron supply of photosystem i. a common way to illustrate this change is by the addition of vitamin c solution. this reduces the 'jelly' by transforming it to a colourless mass. this experiment can be carried out to illustrate the effect of changing cell sizes on sa/v (surface area:volume ratio). this is known as titration.