Enzymes

Question 1

What is an enzyme?

Answer 1

• A biological catalyst that speeds up a reaction without being consumed by the reaction.

Question 2

What is a substrate?

Answer 2

• The molecule that an enzyme acts on

Question 3

How do enzymes work?

Answer 3

• Substrate attaches to the active site of the enzyme.
• Reaction takes place and products are formed.
• When the substrate joins up with the active site, it lowers the energy needed for the reaction to start

Question 4

How do temperatures affect enzymes?

Answer 4

• Rate of an enzymatic reaction increases with increasing temperature.
• Substrates collide with active sites more frequently when the molecules move rapidly.

Question 5

What happens to enzymes above the optimum temperature (37°C)?

Answer 5

• The speed of the enzymatic reaction drops sharply.
• The heat energy disrupts the weak bonds that stabilize the shape of the enzyme and the protein molecule eventually denatures.
• The shape of the active site is changed, and the substrate will no longer fit.

Question 6

How does pH affect enzymes?

Answer 6

• Different enzymes have different optimum pH values.
• However, either side of the optimum the pH affects the structure of enzyme molecule and changes the shape of its active site so that the substrate wil not fit.