Active Site

Question 1

What is the active site of an enzyme?

Answer 1

The region into which the substrate fits.

Question 2

What is special about the shape of the active site?

Answer 2

Active site shape is complementary to shape of substrate.

Charges are also complementary

Question 3

What is the name for when an enzyme and subsrate bind together?

Answer 3

Enzyme-substrate complex

Question 4

What is the original theory of enzyme action?

Answer 4

Lock and Key model

Question 5

What does the Lock and Key Model say?

Answer 5

Active site is the Lock.
Substrate is the key
Both active site and subsrate are fixed in shape

Question 6

What is the new theory for enzyme action?

Answer 6

Induced Fit

Question 7

What does the Induced Fit Hypothesis say?

Answer 7

Active site changes shape slightly to fit around substrate.

Analogy of hand and a glove

Question 8

What is the first stage in an enzyme catalysed reaction?

Answer 8

Substrate fits into active site.

Enzyme-substrate complex formed.

Question 9

What is the second stage in an enzyme catalysed reaction?

Answer 9

Active site changes shape to convert substrate into products.
Forms enzyme-product complex.

Question 10

What is the third stage in an enzyme catalysed reaction?

Answer 10

Products no longer for active site.

Products are released.

Question 11

What is the final stage in an enzyme catalysed reaction?

Answer 11

Active site is now free for another substrate molecule.