Free Printable Enzyme (Cofactors, Inhibitors))

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Enzyme (Cofactors, Inhibitors))

Total questions: 46

Worksheet time: 32mins

Name

Class

Date

Blocking Active site of an enzyme

competitive inhibition

allosteric inhibition

When a molecule can occupy the same active site as the substrate, a situation called __________________ can result

Competitive lnhibition

Allosteric Regulation

Non-Competitive Inhibition

Feedback Inhibition

A receptor site that a molecule can bind to that changes the shape of the active site is called a(n):

Allosteric Site

Active Site

Activation site

Reactant site

Molecules that bind to enzymes and enhance an enzyme's ability are called:

CoFactors

Competitive Inhibitors

Allosteric Inhibitors

what impedes enzymatic reactions by binding to another part of the enzyme?

noncompetative inhibitor

competative inhibitors

coenzymes

cofactors

Many coenzymes are

metals

vitamins

proteins

substances

Organic molecules that temporarily bind to enzymes and enhance an enzyme's ability are called:

CoFactors

CoEnzymes

Allosteric Inhibitors

Allosteric Activators

The inorganic cofactor of amylase is

Cl-

Cl^2-

Zn²⁺

Zn^2-

The enzyme carbonic anhydrase found in the blood has a prosthetic group containing

Cl-

Cl^2-

Zn²⁺

Zn^2-

10.

Competitive inhibition can be overcome by _______________

increase the concentration of substrate

reduce the concentration of enzyme

increase the concentration of enzyme

reduce the concentration of substrate

11.

Consider the following: “Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid”.

Which of the following is correct?

Succinate dehydrogenase is the enzyme, and fumarate is the substrate

Succinate dehydrogenase is the enzyme, and malonic acid is the substrate

Succinate is the substrate, and fumarate is the product

Fumarate is the substrate, and malonic acid is a non-competitive inhibitor

12.

Only a small amount of enzyme is needed for a large amount of substrate because _______

Enzymes do not change at the end of a reaction and as such can be reused

A small amount of enzyme can provide enough energy to continue the reaction

More enzymes are formed while reaction takes place

Enzymes act till completion of a reaction or not at all

13.

The rate of reaction of salivary amylase on starch decreases when the concentration of chloride ion is reduced. Which of the following explains the role of a chloride ion?

substrate

cofactor

active site

inhibitor

14.

State the function of X

Binding site of substrate

Binding site of cofactor

Binding site of reactant

Binding site of inhibitor

15.

How does enzyme lower the activation energy?

Bring substrate closer to each other

Increase the kinetic energy of substrate

Weakening the bonds inside the substrate

Bring substrate together into correct orientation

16.

what reduces the productivity of enzymes by blocking substrates from entering active sites?

non competitive inhibitors

competitive inhibitors

coenzymes

cofactors

17.

Which of the following are the properties of enzyme?

I Enzymes are highly specific.
II All enzymes are denatured at $60\degree c$
III A large number of enzymes is needed to react with large number of substrate.
IV Enzymes lower the activation energy.

I only.

I and IV only.

I, II and III

I, II and IV

18.

The protein part of an enzyme that binds to prosthetic group to form a functional enzyme is called

holoenzyme

apoenzyme

coenzyme

conjugated protein

19.

Which of these cofactors help in making enzyme's active site become fitter with substrate?

Metal ion activators

Coenzyemes

Prosthetic groups

20.

Only protease can catalyses the breakdown of protein. This shows that enzyme

is a biological catalyst

is highly specific in action

able to speed up chemical reaction

may catalyses reversibly

21.

Which of these statements are true about competitive inhibitor?

Inhibitor and substrate has similar structure

The inhibitor binds to the allosteric site

The conformation of active site changed due to the inhibitor

Quantity of product formed is the same as reaction with no inhibitor

22.

Enzymes function as catalysts because they

Increase the free energy of a chemical reaction

Lower the activation energy of a chemical reaction

Decrease the enthalpy of a chemical reaction

Supply the energy to start a chemical reaction

23.

Cofactors for enzyme are

The protein substance

The inorganic substance

The protein and non-protein substances

The non-protein substance

24.

Which is true of non-competitive inhibition?

It is irreversible

The inhibitor binds only to the active site of enzyme

The inhibitor binds to enzyme to lower activation energy

It can be reduced by increasing the concentration of the substrate

25.

What happens to an enzyme when it is denatured?

The activation energy is doubled

The activation energy is lowered

The optimal temperature for enzyme action is doubled

The shape of the enzyme molecule is change

26.

Which type of reversible enzyme inhibitor binds to both the free enzyme and the enzyme-substrate complex?

Non-competitive inhibitor

Competitive inhibitor

End product inhibitor

None of the above

27.

In non-competitive inhibitor, the allosteric inhibitor

Binds to the active site, preventing the substrate from binding to the enzyme

Binds to the substrate, preventing it from binding to the active site

Binds to the enzyme at a site away from the active site, altering the shape of the enzyme

Changes the pH of the environment that the enzyme acts in

28.

Malonic acid could inhibit the action of succinic dehydrogenase on succinic acid because

Malonic acid could react with succinic acid

Malonic acid could bind at the active site of succinic dehydrogenase

Succinic acid could bind at the active site of succinic dehydrogenase

Succinic acid could not bind at the active site of succinic dehydrogenase

29.

If one continues to increase the temperature in an enzyme-catalyzed reaction, the rate of the reaction:

increases and then levels off

decreases and then levels off

increases and then decreases rapidly

decreases and then increases rapidly

30.

Which of these are properties of enzymes?

Reusable

Needed in small quantity

Highly specific

Fibrous protein

31.

Explain model shown above

The active site is exactly complementary to substrate

The active site is highly specific

The active site is flexible

The active site is rigid

32.

What happen when heavy metal ions bind to enzyme?

Substrate is blocked by inhibitor from binding to the active site

Enzyme is permanently denatured

Maximum rate of reaction is still reached at the end

Active site is no longer complementary with substrate

33.

What is structure C?

Substrate-enzyme complex

Substrate-enzyme complement

Enzyme-substrate complement

Enzyme-substrate complex

34.

Watch the animation and identify the hypothesis involved

Lock and Key hypothesis

Induced Fit hypothesis

Enzyme-Substrate hypothesis

35.

Which of the following would increase the rate of enzyme activity in the presence of a non-competitive inhibitor?

add more substrate

add more enzyme

add more inhibitor

reduce the temperature

36.

Which of the following would increase the rate of enzyme activity in the presence of a competitive inhibitor?

add more substrate

add more enzyme

add more inhibitor

reduce the temperature

37.

What kind of inhibition is being shown?

Competitive

Non-competitive

38.

What kind of inhibition is being shown?

Competitive

Non-competitive

39.

Non-competitive inhibitors reduce enzyme activity by

competing for the active site of the enzyme

competing for the allosteric site of the enzyme

denaturing the enzyme preventing substrate binding

changing the shape of the active site by binding to the allosteric site

40.

In a reaction system that involves immobilised enzymes, …………………………

both enzymes and substrate can move about

only enzymes but not substrates can move about

only substrates but not enzymes can move about

neither substrate not enzymes can move about

41.

In using immobilized enzymes to produce lactose free milk, the enzymes will be found in which labelled part of the diagram?

A only

A and B

B and C

B only

42.

What happen when heavy metal ions bind to enzyme?

Substrate is blocked by inhibitor from binding to the active site

Enzyme is permanently denatured

Maximum rate of reaction is still reached at the end

Active site is no longer complementary with substrate

43.

Malonic acid could inhibit the action of succinic dehydrogenase on succinic acid because

Malonic acid could react with succinic acid

Succinic acid could bind at the active site of succinic dehydrogenase

Succinic acid could not bind at the active site of succinic dehydrogenase

Malonic acid could bind at the active site of succinic dehydrogenase

44.

What is the role of Michaelis-Menten equation?

To calculate the free energy

Mathematically explain the relationship of enzyme's velocity and the substrate concentration

Mathematically explain the saturation of enzyme in substrate

45.

Affinity is a word to describe how effective is the binding between the enzyme and the substrate. What is the relationship of Km with affinity?

High Km, High affinity

High Km, Low affinity

With lower Km, the enzyme can reach Vmax faster

46.