The Effect of Temperature on the Rate of Reaction of Yeast

1309 Words3 Pages

The Effect of Temperature on the Rate of Reaction of Yeast

Aim

My aim is to view the effects of different temperatures on the rate of

respiration of yeast in a glucose solution. I will do this by

measuring the rate of which carbon dioxide is given off (CO2) by the

yeast.

Scientific knowledge

====================

From previous experiments I have learnt several things about yeast and

enzymes. I have learnt that an enzyme is a natural catalyst,

(something that speeds up the experiment without altering the out

come.) Yeast is a fungus that is used in fermentation this is because

it respires anaerobically and aerobically, the anaerobic respiration

is the useful bit in fermentation as it produces ethanol (alcohol).

The sucrose solution that the yeast is put in is needed as energy so

that the enzymes in yeast can respire. The equation is:

[IMAGE]Glucose Carbon dioxide + Ethanol

From a similar experiment with amylase I have seen that a change in

temperature can drastically change the rate at which yeast respires.

This is because of a theory, which is called the "collision theory"

this says that when something is heated then it will move faster thus

there will be more collisions between the substrates and the enzyme

(glucose and the yeast).

The increase in temperature increases the efficiency of the enzymes up

to a point where they are at maximum efficiency this is about 40°C;

this is called the optimum temperature. After this point the enzymes

begin to denatured, this is where they are given so much kinetic

energy what the bonds break and this leads to the active site changing

shape.

This leads onto the lock and key theory that says that the substrate

and the enzyme fit together like a lock and key and when the active

site changes shape they cannot connect and so the reaction doesn't

take place.

http://regentsprep.org[IMAGE]

The pH of the solution would alter the rate of the reaction if it was

changed therefore I must keep it constant, it will not change.

Open Document