Enzymes

Question 1

What are the function of enzymes?

Answer 1

• acts as a biological catalyst which is a substance that speeds up a chemical reaction without itself being used up
• enzymes are not a part of the reaction and reduce the activation energy of a chemical process

Question 2

Describe a model of enzyme action

Answer 2

1. Initiation: reactants bind to the active site in a specific orientation, forming an enzyme-substrate complex
2. Transition state facilitation: interactions between enzyme and substrate lower the activation energy
3. Termination: products have lower affinity for the active site and are released. Enzyme is unchanged after the reaction

Question 3

Describe the regulation of metabolic pathways

Answer 3

• end-product or feedback inhibition regulates the whole pathway

Question 4

What are the two types of enzyme regulation?

Answer 4

• Competitive Inhibition

- Allosteric Regulation

Question 5

What is competitive inhibition?

Answer 5

• the substrates cannot bind when a regulatory molecule binds to the enzyme’s active site

Question 6

Describe allosteric regulation

Answer 6

• active site becomes available to the substrates when a regulatory molecule bins to a different site on the enzyme
• the active state becomes unavailable to the substrates when a regulatory molecule binds to a different site on the enzyme

Question 7

Which is more efficient: competitive inhibition or allosteric regulation and why?

Answer 7

• Allosteric regulation because it use less regulatory molecules per substrate
• Deactivates the protein completely

Question 8

Describe cooperative allosteric transition

Answer 8

• occurs with two or more subunits of a single enzyme
• the transition between one inhibitor replacing a substrate in the enzyme is a difficult transition, but the implementation of a second inhibitor is an easier transition