SC.912.18.11: Enzyme Activity Review

Explain how enzymes work in biological systems.

• Enzymes speed up the rate of reactions by increasing activation energy

• Enzymes inhibit the progress of chemical reactions

• Enzymes lower the activation energy required for chemical reactions to occur.

• Enzymes have no effect on the activation energy of reactions

Answer explanation

Enzymes lower the activation energy required for chemical reactions to occur.

What factors can affect enzyme activity?

• Time of day, Weather conditions, Distance from the equator

• Temperature, pH, substrate concentration, enzyme concentration, presence of inhibitors or activators

Answer explanation

Factors that can affect enzyme activity include temperature, pH, substrate concentration, enzyme concentration, and the presence of inhibitors or activators.

Describe the lock and key model of enzyme-substrate interaction.

• The lock and key model of enzyme-substrate interaction involves a specific interaction between the enzyme's active site and the substrate molecule, resembling a lock and key mechanism.

• In the lock and key model, enzymes change shape to fit the substrate

• Lock and key model suggests enzymes can bind to any substrate regardless of shape

• The lock and key model involves enzymes physically locking onto substrates with a key-like structure

Answer explanation

The lock and key model of enzyme-substrate interaction involves a specific interaction between the enzyme's active site and the substrate molecule, resembling a lock and key mechanism.

Explain the concept of enzyme denaturation.

• Enzyme denaturation is caused by optimal conditions for enzyme activity

• Enzyme denaturation occurs when enzymes lose their structure and function due to extreme conditions.

• Enzyme denaturation is the process of enhancing enzyme activity

• Enzyme denaturation is reversible and does not affect enzyme function

Answer explanation

Enzyme denaturation occurs when enzymes lose their structure and function due to extreme conditions.

How do inhibitors affect enzyme activity?

• Inhibitors only affect enzyme activity in the presence of cofactors

• Inhibitors enhance enzyme activity by binding to the enzyme

• Inhibitors have no effect on enzyme activity

• Inhibitors can either competitively or non-competitively inhibit enzyme activity by binding to the enzyme and altering its function.

Answer explanation

Inhibitors can either competitively or non-competitively inhibit enzyme activity by binding to the enzyme and altering its function.

Which enzyme is responsible for converting hydrogen peroxide into water and oxygen?

• Catalase

• Lactase

• Helicase

• Protease

Label the parts of the enzyme model

a

b

c

d

Enzyme

Substrate

Active site

Products

Changes in temperature and pH can decrease an enzyme’s activity by breaking

• peptide bonds

• hydrogen bonds

• amino acids

• sulfur bonds

Enzymes are proteins that have a three-dimensional shape that is specific to a particular substrate. Environmental conditions can change the shape of the protein.

What is the most likely result if the shape of the enzyme changes?

• The substrate will change its shape to match the enzyme.

• The enzyme will no longer be able to catalyze the reaction with the substrate.

• The products made from the enzyme and the substrate will be changed.

• The enzyme will be able to bind to more diverse substrates than before.

A prolonged period of high fever is dangerous to humans because... (choose TWO that apply)

• It makes the enzymes work faster

• It denatures the enzyme and stops working

• It can make the enzyme function better than it did before

• It can change the shape of an enzyme so it can not bind to the right substrate