T8 - Biological Molecules - ENZYMES

Question 1

what is an enzyme

Answer 1

a biological catalyst

Question 2

what does an enzyme do

Answer 2

speeds up the rate of a chemical reaction without being changed or used up in the reaction

Question 3

Why are enzymes important?

Answer 3

They maintain reaction speeds of all metabolic reactions (all the reactions that keep an organism alive) at a rate that can sustain life

Question 4

How do enzymes work?

Answer 4

-the substrate binds to the active site of the enzyme
-the enzyme and substrate form a substrate complex
-the products are released which catalyse the reaction

Question 5

how temperature changes can affect enzyme function, including changes to the shape of active site

Answer 5

increasing temperature speeds up the rate of reaction until the enzyme becomes denatured. The active site of the enzyme has been denatured and has changed shape meaning it can no longer bind to the active site.

Question 6

investigate how enzyme activity can be affected by changes in temperature

Answer 6

• add a set amount of starch solution to a test tube and heat to a set temp using a beaker of water and a bunsen burner
• add a drop of iodine to each of the wells of a spotting tile
• use a syringe to add amylase to the starch solution and mix well
• every minute, transfer a droplet of solution to a new well of iodine solution and wait for it to turn blue-black
• repeat the transfer process until the iodine solution stops turning blue-black meaning that the amylase solution has broken down all of the starch
• repeat the investigation at a range of temperatures (20-60 degrees celcius)

Question 7

understand how enzyme function can be affected by changes in pH altering the active site

Answer 7

• add a drop of iodine to each of the wells of a spotting tile
• add amylase into a test tube using a syringe
• add buffer solution (at pH 2) to the test tube using a syringe
• use another test tube and add starch solution to the amylase and buffer solution and mix well
• every ten seconds, transfer a droplet of the solution onto a new well of the spotting tile
• repeat the transfer process until the iodine stops turning blue black
• record the time taken for the reactions to be completed
• repeat the investigation using a range of pH values.