Enzymes | Free Mock Test Series | Target Mdcat 2025

Question 1

Which of the following is a characteristic feature of enzymes?

They increase the activation energy

They are used up in the reaction

They speed up reactions without being consumed

They are always made up of carbohydrates

Question 2

Which component of an enzyme determines its specificity?

Active site

Allosteric site

Hydrophobic tail

Zinc cofactor

Question 3

What happens to enzyme activity when the temperature is increased beyond optimum?

It increases continuously

It stays constant

It decreases due to denaturation

It becomes reversible

Question 4

At which temperature do most human enzymes function optimally?

0°C

25°C

37°C

100°C

Question 5

What effect does extreme pH have on enzyme activity?

Enhances enzyme activity

No effect at all

Causes denaturation of enzyme

Increases substrate concentration

Question 6

Which of the following is an example of a competitive inhibitor?

Cyanide

Sulfanilamide

Penicillin

ATP

Question 7

How does a non-competitive inhibitor affect enzyme activity?

Binds at the active site

Reduces the enzyme's affinity for the substrate

Changes enzyme shape by binding elsewhere

Increases enzyme activity

Question 8

Which of the following best defines an enzyme?

A carbohydrate that speeds up chemical reactions

A lipid that stores energy

A protein that acts as a biological catalyst

A hormone that regulates metabolism

Question 9

What is the term for the minimum amount of energy required to start a reaction?

Enzyme energy

Activation energy

Kinetic energy

Potential energy

Question 10

What happens when enzyme concentration is increased while substrate remains constant?

Rate decreases

Rate increases initially then levels off

No change

Reaction stops

Question 11

Enzymes are usually composed of:

Proteins

Lipids

Carbohydrates

DNA

Question 12

What name is given to the substance upon which an enzyme acts?

Product

Catalyst

Substrate

Cofactor

Question 13

Which model explains how enzyme and substrate fit together?

Fluid mosaic model

Lock and key model

Sliding filament model

Central dogma

Question 14

Which enzyme works best in highly acidic conditions?

Lipase

Trypsin

Pepsin

Amylase

Question 15

Which enzyme is used to break down hydrogen peroxide?

Lipase

Catalase

Amylase

Protease

Question 16

What kind of protein is an enzyme?

Structural protein

Transport protein

Catalytic protein

Storage protein

Question 17

The reaction rate of an enzyme is highest when:

Substrate is absent

Enzyme is denatured

Temperature is optimal

pH is extremely high

Question 18

Which factor does NOT affect enzyme activity?

Temperature

pH

Substrate concentration

Color of enzyme

Question 19

Allosteric inhibition occurs when:

Substrate binds to enzyme

Inhibitor binds to active site

Inhibitor binds to other site and alters shape

Temperature is too high

Question 20

Which of these is an example of an enzyme-substrate complex?

Glucose

Lactose + water

Sucrase-sucrose

Starch

Question 21

Which factor increases enzyme activity up to a point but then causes denaturation?

Increasing temperature

High salt concentration

Darkness

Constant pH

Question 22

Which structure level is crucial for enzyme function?

Primary

Secondary

Tertiary

Quaternary

Question 23

Which substance is needed by some enzymes for activity?

Cofactor

Glycogen

Phospholipid

RNA

Question 24

In competitive inhibition:

Inhibitor binds elsewhere on enzyme

Inhibitor destroys the enzyme

Inhibitor mimics substrate and binds active site

Substrate binds more strongly

Question 25

Pepsin works best at which pH?

2

5

7

9

Question 26

The function of enzymes in cells is to:

Store energy

Provide structure

Speed up chemical reactions

Act as hormones

Question 27

Which enzyme digests starch?

Lipase

Amylase

Protease

Maltase

Question 28

Why do enzymes show specificity?

Due to universal active sites

Due to shape of active site matching substrate

Due to hydrophobic nature

Because they are always acidic

Question 29

Which of the following enzymes digests protein in the stomach?

Pepsin

Trypsin

Lipase

Amylase