B2: ENZYMES

Question 1

What is an enzyme?

Answer 1

a biological catalyst

Question 2

what is lock and key theory?

Answer 2

enzymes have a specific shape of active site that is complementary to a specific substrate

Question 3

How does temp affect enzymes?

Answer 3

-a higher temp increases the rate of the reaction at first
-if it gets too hot the bonds holding the enzyme together start to break which changes the shape of the enzyme’s active site which means the substrate won’t be able to bind with the enzyme
-enzyme is denatured

Question 4

How does pH affect enzymes?

Answer 4

-if pH is too high or too low it can interfere with the bonds holding the enzyme together
-enzyme denatures

Question 5

RP - The effect of pH on enzyme activity

Answer 5

amylase catalyses the breakdown of starch into glucose. starch can be detected with iodine (if starch is present idodine changes from browny-orange to blue black)
-put a drop of iodine into every well of a spotting tile
-use a bunsen burner to heat water in a beaker until 35°C
-use a syringe to add 1cm^3 of amylase solution and 1cm^3 of a buffer solution with a pH of 5 to a boiling tube. using test tube holders put the tube into the beaker of water for 5 mins
-use a different syringe to add 5cm^3 of a starch soluton to the boiling tube
-mix the contents of the boiling tube and start a stopwatch
-use contiuous sampling to record how long it takes for all the amylase to break down the starch: use a pippete to take a fresh sample from the boiling tube every 30 secs and put a drop into a well. when the iodine solution remains browny-orange starch is no longer present
-repeat the whole experiment with buffer olutions of different pH values to see how pH affects time taken for starch to be broken down

Question 6

What are the 4 digestive enzymes?

Answer 6

-amylase
-carbohydrase
-protease
-lipase

Question 7

What does amylase break down and what is the product?

Answer 7

-breaks down: starch
-products: glucose

Question 8

What does carbohydrase break down and what is the product?

Answer 8

-breaks down: carbohydrates
-product: glucose

Question 9

What does protease break down and what is the product?

Answer 9

-breaks down: proteins
-product: amino acids

Question 10

What does lipase break down and what is the product?

Answer 10

-breaks down: lipids
-product: glycerol and fatty acids

Question 11

Where is amylase produced?

Answer 11

-salivary glands
-pancreas

Question 12

Where is carbohydrase produced?

Answer 12

-pancreas
-small intestine

Question 13

Where is protease produced?

Answer 13

-stomach
-pancreas
-small intestine

Question 14

Where is lipase found?

Answer 14

-pancreas