Effect of temperature and ph on enzymes

Question 1

Describe how increasing temperature effects enzymes speed?

Answer 1

As we increase the temperature the activity of the enzyme increases because the enzyme and substrate have more energy and are moving faster which causes more collisions per second between the substrate and the active site
At a certain point the enzyme is working at the fastest possible rate, and this is called the optimum temperature because there is the maximum number of successful collisions between the substate and the active site
After we increase the enzyme above the optimum the activity of the enzyme rapidly decreases to 0 because at high temperatures the enzyme molecule vibrates causing a change in the shape of the active site and the active site to de-nature

Question 2

Describe how changing the pH can affect enzymes speed?

Answer 2

The enzyme has an optimum pH where the activity is maximum
If we change the pH from the optimum to be more acidic or alkaline the activity drops to 0
This is because if the conditions aren’t right, it de-natures

Question 3

Why are different pHs required from different enzymes?

Answer 3

Each enzyme requires a different pH to work at optimum

Question 4

Describe how to investigate the effect of pH on the enzyme amylase?

Answer 4

Place one drop of iodine into each well of a spotting tile
Then get 3 test tubes and add starch solution to one, amylase solution to another and a pH 5 buffer solution to the third
Then add all three test tubes to a water bath at 30 degrees Celsius and leave them for 10 minutes
Then mix all three of the test tubes into one tube and return it to the water bath
Then start a stopwatch and after 30 seconds add one drop of the solution to each spotting tile
The iodine in the spotting well should turn blue-black showing that starch is present
Then take a sample every 30 seconds until the iodine remains orange
This tells us that starch isn’t present
Then repeat the experiment using different pH buffers

Question 5

Problems with this experiment?

Answer 5

Sample are only taken every 30 seconds, so we only have an approximate time for the reaction to complete
It isn’t always obvious when the iodine changes from orange to blue-black