3.1.4.2 Enzyme Action

Question 1

Define Enzyme.

Answer 1

They act as biological catalysts to speed up chemical reactions by providing a different pathway with a lower Ea. - without being used up itself

Question 2

How does the induced fit model explain why enzymes are so specific?

Answer 2

it shows that enzymes only bond to one particular substrate.

the substrate has to be the right shape and has to make the active site change shape in the right way.

Question 3

Describe the induced fit model of enzyme action.

Answer 3

the complementary substrate binds to the active site of the enzyme to form, an enzyme-substrate complex. As the substrate binds, the active site changes shape slightly, which provides a better fit.
The substrate is broken down/joined together to form the products

Question 4

How does the enzyme-substrate complex lower the Ea?
Explain this

Answer 4

1. if two substrate molecules need to be joined, being attached to an enzyme holds them closer together, reducing repulsion between the molecules, so they bond more easily.
2. if the enzyme is catalysing a breakdown reaction, fitting into the active site puts a strain on bonds in the substrate, so they substrate molecule easily breaks up.