The Effect of the Concentration Amylase on the Rate of Breakdown of Starch

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The Effect of the Concentration Amylase on the Rate of Breakdown of Starch

Investigation: To find the effect of the concentration amylase on the

rate of breakdown of starch.


The lower the concentration of amylase, the slower the breakdown of

starch will be. If you double the amount of amylase, the breakdown of

starch will be quicker because there are twice as many active sites.

I expect to see a graph like:


Rate of



Concentration of amylase


Enzymes are made of long protein molecules, which are folded up so

they have an irregular globular shape. One part of the surface is the

active site and fits exactly into the substrates, which then reacts.

When a substrate molecule collides with an enzyme it becomes attached

to the active site of the enzyme and the reaction then takes place.

The products then leave the active site, which can be used again.



Temperature effects the efficiency of the enzymes. The higher the heat

the greater the proportion of damage on the enzyme. The enzyme will no

longer fit in the active site. Below normal temperatures, enzymes

become less and less active, due to reductions in speed of molecular

movement, but this is reversible, so enzymes work effectively when

returned to normal temperature.

In digestion the substance which is present at the beginning of the

experiment is called the substrate. The substance made at the end of

the reaction is called the product. For example, in saliva there is an

enzyme known as amylase (which is being used in this investigation).

It catalyses the breakdow...

... middle of paper ...

...ld have been

the fact that the starch was left out so long. Being left out for a

while meant that the starch became viscous and stuck to the sides of

the boiling tube. This could have resulted in a variation of the

volume of starch being mixed together with the different

concentrations of amylase.

In the future a more accurate measuring cylinder could be used because

the measuring cylinder used in this investigation was only to the

nearest 0.1 cm3. The colour of the iodine solution could have also

caused some inaccuracies because different shades of brown could have

been chosen. This would have made the time taken for the starch to

break down different.

Overall, I think I used my time well, I followed my method and gained

fairly accurate results in the time given. My prediction was supported

by the results.

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