Download Enzyme Action Worksheet

Name: ________________________________
Worksheet Enzyme Action
In this worksheet, we will practice describing the properties of enzymes, and outlining the
‘lock and key’ theory of enzyme action.
Q1: Fill in the blank: The reactant that an enzyme will bind to, due to its complementary
shape, is a/an .

A active site

B protein

C catalyst

D substrate

E product
Q2: Enzymes act as catalysts. What does a catalyst do?

A A catalyst speeds up the rate of a reaction.

B A catalyst increases the number of reactants in a reaction.

C A catalyst always maintains a constant rate of reaction.

D A catalyst ensures a reaction never ends.

E A catalyst slows down the rate of a reaction.
Q3: Which of the following statements correctly defines an enzyme?

A An enzyme is a product of digestion.

B An enzyme is a molecule that has been broken down.

C An enzyme is a biological catalyst.

D An enzyme is an inorganic catalyst.

E An enzyme is a fast reaction.
Q4: Which of the following is not a reaction, or a type of reaction, that involves enzymes?

A Photosynthesis

B Respiration

C Breaking down large molecules into smaller ones

D Diffusion

E Synthesizing large molecules from smaller ones
Q5: With reference to enzymes, what does “denatured” mean?

A The enzyme’s active site has been irreversibly changed.

B The enzyme has been killed.

C The enzyme has been used as much as it can be and must be replaced.

D The enzyme has been damaged and subsequently works more slowly.

E The enzyme’s protein structure has been stretched.
Q6: Which of the following best describes the lock and key theory of enzyme action?

A The enzyme and substrate have identical shapes, like a “lock and key.”

B The enzyme is the “lock” into which the substrate, or the “key,” fits.

C Once the enzyme and substrate have joined, they are locked together and cannot
be separated.

D The substrate is the “lock” into which the enzyme, or the “key,” fits.
Q7: The enzyme in the diagram has had its active site irreversibly changed. What scientific
term describes this change?

A Deformation

B Decomposition

C Denaturation

D Dying

E Deposition
Q8: A diagram of an enzyme and some substrates is shown. Which substrate will the
enzyme bind to?

AZ

BX

CY

DV
Q9: A diagram of an enzyme and some substrates is provided. Which substrate will the
enzyme bind to?

AY

BX

CZ

DV
Q10: The enzyme catalase catalyzes the reaction that breaks down hydrogen peroxide into
water and oxygen. The table shows how much oxygen is produced over time when this
reaction occurs with and without catalase.
In which reaction is the rate of oxygen production lower?

A The rate is the same in both reactions.

B The rate is lower in the reaction with catalase.

C The rate is lower in the reaction without catalase.
Q11: In the diagram provided, a section is labeled with a ?. This is where the substrate will
bind. What is the scientific term given to this part of the enzyme?

A Enzyme–substrate complex

B Active site

C Tertiary site

D Joining site

E Complementary site
Q12: Which of the following statements correctly links enzymes, substrates, and active sites?

A The enzyme’s active site is constantly changing to have a complementary shape
to a range of substrates.

B The substrate has an active site that has a complementary shape to a range of
enzymes.

C The substrate has an active site that has an identical shape to a specific enzyme.


D The enzyme has an active site that has an identical shape to a range of
substrates.
E The enzyme has an active site that has a complementary shape to a specific
substrate.
Q13: The diagram provided shows a basic outline of the lock and key theory.
Which letter represents the enzyme?

AZ

BX

CY

D None
Which letter represents the substrate?

AZ

BX

CY

D None
Which letter represents the products of this reaction?

AX

BZ

CY

D None
Q14: The diagram provided shows a basic outline of the lock and key theory.
Which label represents the substrate?

AY

BZ

CX

D None
What has happened to the substrate?

A It has been used to form a polymer.

B It has been broken down.

C It has been joined in a reaction.

D It has been dissolved.
In which step has an enzyme–substrate complex formed?
Q15: The enzyme catalase catalyzes the reaction that breaks down hydrogen peroxide into
water and oxygen. The graph shows how much oxygen is produced over time when this
reaction occurs with and without catalase.
Which of the following statements correctly describes the trend shown?

A The reaction produces more oxygen when catalase is present.

B The reaction produces more oxygen when catalase is not present.

C The reaction produces oxygen at a quicker rate when catalase is present.

D The reaction produces oxygen at a quicker rate when catalase is not present.

E There is no correlation between the rate of oxygen production and the presence of
catalase.
Q16: A diagram of an enzyme and some substrates is shown. Which substrate will the
enzyme bind to?

AV

BX

CY

DZ
Q17: The graph provided shows how the addition of an enzyme affects a biochemical
reaction. What key aspect of this reaction has changed with the addition of an enzyme?

A The volume of products formed has decreased.

B The free energy of the reaction has increased.

C The time taken for the reaction to become complete has increased.

D The activation energy has been lowered.

E There have been no obvious changes.
Q18: The graph provided shows the reaction profile of a biological reaction. Which letter
indicates the activation energy?

AX

BY

CZ

DW