Enzymes

Question 1

What are enzymes AND why are they essential.

Answer 1

Enzymes are proteins that act as biological catalysts.

Enzymes are essential to keep chemical reactions in our bodies fast enough for survival.

Question 2

What is a catalyst

Answer 2

Something that increases the rate of reaction without being changed by the reaction itself.

Question 3

Where does the molecule bind in the Enzyme

Answer 3

Active site

Question 4

What is the molecule the enzyme acts on called?

Answer 4

Substrate

Question 5

How does a enzyme work

Answer 5

Enzymes are specific to one substrate. The substrate specially fits in that enzymes active side and it breaks it down

Question 6

What affects the rate of enzyme activity

Answer 6

temperature and pH

Question 7

How does pH affect the rate of enzyme activity

Answer 7

The optimum pH for most enzymes is 7 but some that are produced in acidic conditions, such as the stomach, have a lower optimum pH (pH 2) and some that are produced in alkaline conditions, such as the duodenum, have a higher optimum pH (pH 8 or 9)
If the pH is too high or too low, the bonds that hold the amino acid chain together to make up the protein can be destroyed
This will change the shape of the active site, so the substrate can no longer fit in
The enzyme will denature and activity will stop

Question 8

How does temperature affect the rate of enzyme activity

Answer 8

If temperature is low, activity is low as the molecules have little energy therefore rates of successful collision is less therefore working slower
If temperature too high the enzyme would break as the high temperatures break the active site.
Enzymes work fastest at optimum temperature which is 37.

Question 9

What is denaturation

Answer 9

when the substrate can’t fit into the enzyme active site. anymore. It is irreversible

Question 10

investigate how enzyme activity can be affected by changes in temperature

Answer 10

1. Heat the strach solutions.
2. add iodine solution to well of the spotting tiles
3. Mix the strach solution with amylase
4. with a pipette add droplets of the solution to the iodine solution every 1 minute
5. continue until the iodine solution stops turning blue black (this means the amylase has broken down all the starch)
6. write down the time taken for the reaction to be complete.
7. repeat the experiment with different temperatures and repeat 3 times to get accurate results
8. the higher the temperature the faster the rate of reaction should be

Question 11

investigate how enzyme activity can be affected by changes in pH

Answer 11

1. add one drop iodine solution to well of the spotting tiles
2. take 3 tests tube. first test tube add 2cm3 of starch solution, 2cm3 of amylase solution and 2cm3 of pH 5 buffer solution
3. place all three test tubes in a water bath with a temperature of 30 and allow them to reach correct temperature
4. combine the 3 solutions into one and mix with a stirring rod, return it to the water bath and start a stop watch
5. after 10 seconds add a drop of the solution into the spotting tile that contain the iodine
6. continue until the iodine solution stops turning blue black (this means the amylase has broken down all the starch).
7. write down the time taken for reaction to be complete.
8. . repeat experiment with different pH levels buffers 3 times