Enzymes

Question 1

What are enzymes?

Answer 1

Biological catalysts:

-speed up chemical reactions without being used up

Question 2

What is the active site?

Answer 2

• Enzymes are proteins
• contain an area with a specific 3-D structure called the active site
• This is where chemical reactions take place

Question 3

What is meant by the phrase “Enzymes are specific”?

Answer 3

• They only react with their substrate
• The substrate has a specific shape that is complementary to the active site
• Fits like a “Key in a lock”

Question 4

What are products?

Answer 4

The enzymes convert molecules (the substrates) into the different molecules known as products

Question 5

What is an E-S C?

Answer 5

Enzyme + substrate is called and Enzyme-substrate complex

Question 6

What is a hydrolysis reaction?

Answer 6

A reaction where the substrate is broken by the addition of water

Question 7

What is a condensation reaction?

Answer 7

A reaction where the product is formed by the removal of water

Question 8

Explain the Induced fit theory of enzyme action

Answer 8

• The active site of the enzyme is a specific shape and only catalyses one reaction
• The substrate with the correct shape enters the active site
• it is thought that the active site changes shape slightly once the substrate has entered it
• This makes the active site fit more closely around the substrate and helps the reaction to take place more efficiently

Question 9

How does temperature affect the rate of an enzyme-catalysed reaction?

Answer 9

• As the temperature increases, the enzymes and substrates gain more kinetic energy and move around faster
• This increases the chance of the substrates colliding with the active sites of the enzymes with sufficient energy for the reactions to occur, so the rate of reaction increases
• The rate of reaction is fastest at the optimum temperature
• Above the optimum temperature, the enzyme begins to denature and the rate of reaction decreases until it stops when all of the enzymes are fully denatured
• Once denatured, the functional shape of the enzymes active site is altered, and it can no longer catalyse the reaction, even when the temperature is lowered

Question 10

How does pH affect the rate of an enzyme-catalysed reaction?

Answer 10

• Different enzymes work best at different pH values
• As the pH moves further away from the optimum, in either direction, the enzyme begins to denature and the rate of reaction falls
• Once denatured, the functional shape of the enzyme’s active site is destroyed and the enzyme can no longer catalyse the reaction, even when the pH is returned to optimum

Question 11

What is the role of amylase? Where is it produced?

Answer 11

• Breakdown Starch into small, soluble Maltose molecules

- Produced in the salivary glands and pancreas

Question 12

What is the role of Protease? Where is it produced?

Answer 12

• Breakdown Protein into smaller, soluble amino acids

- Produced in the stomach and pancreas

Question 13

What is the role of Lipase? Where is it produced?

Answer 13

• Breakdown Lipids into smaller, soluble fatty acids and glycerol molecules
• Produced in the pancreas

Question 14

What is the role of Maltase? Where is it produced?

Answer 14

• Breakdown Maltose into smaller, soluble Glucose molecules

- Produced in the small intestine