Enzymes: Interactive Learning Quizzes for Sixth Form Biology

Question 1

Which of the following factors **DOES NOT** affect enzyme activity?

Accepted Answer

Concentration of product

Answer

Temperature

Answer

pH

Answer

Concentration of enzyme

Question 2

Which of the following is an example of an allosteric enzyme?

Accepted Answer

Aspartate transaminase

Answer

Hexokinase

Answer

Glucokinase

Answer

Pyruvate kinase

Question 3

Which of the following is **NOT** a role of enzymes in living organisms?

Accepted Answer

Transporting ions across membranes

Answer

Catalysing metabolic reactions

Answer

Regulating gene expression

Answer

Digesting food

Question 4

Enzyme inhibitors are used in medicine to:

Accepted Answer

Block the action of harmful enzymes

Answer

Increase the activity of enzymes

Answer

Change the specificity of enzymes

Answer

Destroy enzymes

Question 5

Which conditions are most likely to result in the highest enzyme activity?

Accepted Answer

Temperature at optimum, substrate concentration at optimum, and pH at optimum

Answer

Temperature below optimum

Answer

Substrate concentration below optimum

Answer

pH below optimum

Question 6

Enzymes are essential for life because they:

Accepted Answer

Control the rate of biochemical reactions in cells.

Answer

Store and release energy for cells.

Answer

Transport molecules across cell membranes.

Answer

Synthesize DNA.

Question 7

The Michaelis-Menten constant (Km) represents:

Accepted Answer

The substrate concentration at which the enzyme is half-saturated

Answer

The maximum velocity of the enzyme-catalyzed reaction

Answer

The affinity of the enzyme for its substrate

Answer

The rate of enzyme turnover

Question 8

Competitive enzyme inhibition occurs when:

Accepted Answer

The inhibitor binds to the enzyme's active site

Answer

The inhibitor binds to a different site on the enzyme, causing a conformational change

Answer

The inhibitor binds to the enzyme-substrate complex

Answer

The inhibitor binds to the product of the enzyme-catalyzed reaction

Question 9

Which of the following is a metalloenzyme?

Accepted Answer

Carbonic anhydrase

Answer

Alcohol dehydrogenase

Answer

Chymotrypsin

Answer

Hexokinase

Question 10

The transition state of an enzyme-catalyzed reaction is:

Accepted Answer

The activated state of the substrate

Answer

The highest energy state of the reaction

Answer

The lowest energy state of the reaction

Answer

The state of the enzyme-substrate complex

Question 11

Which of the following is a proteolytic enzyme?

Accepted Answer

Pepsin

Answer

Amylase

Answer

Lipase

Answer

Sucrase

Question 12

The optimum pH for most enzymes is around:

Accepted Answer

7-9

Answer

2-3

Answer

4-6

Answer

10-12

Question 13

What is the optimal temperature range for most human enzymes to function efficiently?

Accepted Answer

25-37°C

Answer

0-10°C

Answer

50-60°C

Answer

80-100°C

Question 14

Which of the following describes the primary structure of an enzyme?

Accepted Answer

A linear chain of amino acids

Answer

A three-dimensional arrangement of amino acids

Answer

A complex of multiple polypeptide chains

Answer

A structure with repeating patterns of α-helices and β-sheets

Question 15

What is the role of cofactors in enzyme catalysis?

Accepted Answer

They provide the active site with the necessary chemical environment for catalysis.

Answer

They are organic molecules that participate directly in enzyme reactions.

Answer

They are metal ions that help to stabilize the enzyme structure.

Answer

They are inhibitors that bind to the enzyme and reduce its activity.

Question 16

The Michaelis constant (Km) of an enzyme represents:

Accepted Answer

The substrate concentration at which the enzyme reaches half of its maximum velocity.

Answer

The maximum velocity of the enzyme-catalyzed reaction.

Answer

The time it takes for an enzyme to reach its maximum velocity.

Answer

The concentration of inhibitor required to decrease the enzyme activity by half.

Question 17

Which of the following enzymes is involved in the breakdown of glucose during glycolysis?

Accepted Answer

Hexokinase

Answer

Pepsin

Answer

Lipase

Answer

Catalase

Question 18

How does increasing substrate concentration typically affect enzyme activity?

Accepted Answer

It increases enzyme activity until the enzyme is saturated with substrate.

Answer

It decreases enzyme activity by reducing the availability of free enzyme.

Answer

Enzyme activity remains unaffected by changes in substrate concentration.

Answer

It initially increases enzyme activity, then decreases it as substrate concentration becomes excessive.

Question 19

Distinguish between competitive and non-competitive enzyme inhibition.

Accepted Answer

Competitive inhibitors bind to the active site, hindering substrate binding, while non-competitive inhibitors bind elsewhere on the enzyme.

Answer

Non-competitive inhibitors bind to the active site, blocking substrate binding, while competitive inhibitors bind elsewhere on the enzyme.

Answer

Competitive inhibitors enhance enzyme activity, whereas non-competitive inhibitors reduce it.

Answer

Non-competitive inhibitors enhance enzyme activity, whereas competitive inhibitors reduce it.

Question 20

What is the primary function of coenzymes in enzymatic reactions?

Accepted Answer

They participate in electron transfer reactions during catalysis.

Answer

They provide the enzyme with the energy required for catalysis.

Answer

They assist in substrate orientation for efficient catalysis.

Answer

They regulate the overall activity of the enzyme.

Question 21

Which of the following enzymes is classified as an allosteric enzyme?

Accepted Answer

Hexokinase

Answer

Ribozyme

Answer

Amylase

Answer

Lipase

Question 22

State the optimal pH range for most enzymes:

Accepted Answer

Varies according to the enzyme

Answer

Acidic (below pH 7)

Answer

Neutral (pH 7)

Answer

Alkaline (above pH 7)

Question 23

Which of the following factors does NOT affect enzyme activity?

Accepted Answer

Light intensity

Answer

Temperature

Answer

pH

Answer

Enzyme concentration

Question 24

The Michaelis constant (Km) represents:

Accepted Answer

The substrate concentration at which the enzyme is half-saturated

Answer

The maximum velocity of the enzyme-catalyzed reaction

Answer

The rate constant for the enzyme-catalyzed reaction

Answer

The equilibrium constant for the enzyme-catalyzed reaction

Question 25

Which type of enzyme inhibition involves the inhibitor binding to the active site of the enzyme?

Accepted Answer

Competitive inhibition

Answer

Non-competitive inhibition

Answer

Uncompetitive inhibition

Answer

Mixed inhibition

Question 26

Which of the following is NOT a medical application of enzymes?

Accepted Answer

Antibiotics

Answer

Digestive aids

Answer

Blood thinners

Answer

Detergents

Question 27

Which enzyme is responsible for hydrolyzing starch?

Accepted Answer

Amylase

Answer

Protease

Answer

Lipase

Answer

Nuclease

Question 28

Which of the following is a metalloenzyme?

Accepted Answer

Cytochrome oxidase

Answer

Alcohol dehydrogenase

Answer

Lysozyme

Answer

RNA polymerase

Question 29

The active site of an enzyme is:

Accepted Answer

A specific region that binds and interacts with the substrate.

Answer

A random location on the enzyme.

Answer

The site where the enzyme is produced.

Answer

The entire surface of the enzyme.

Question 30

Which of the following factors can influence enzyme activity?

Accepted Answer

Temperature, pH, and substrate concentration

Answer

Wind speed

Answer

Number of students in class

Answer

Light intensity

Question 31

Most enzymes in the human body function optimally at a temperature of:

Accepted Answer

37°C

Answer

0°C

Answer

25°C

Answer

100°C

Question 32

Competitive inhibition occurs when the inhibitor:

Accepted Answer

Binds to the active site, competing with the substrate for binding.

Answer

Binds to a site other than the active site, altering enzyme conformation.

Answer

Increases the activation energy of the enzyme-substrate complex.

Answer

Decreases the rate of product formation.

Question 33

What is the primary role of coenzymes in enzyme reactions?

Accepted Answer

To provide additional functional groups or carry electrons, facilitating chemical reactions.

Answer

To decrease the specificity of the enzyme.

Answer

To increase the activation energy of the reaction.

Question 34

Which of the following is an example of a zymogen?

Accepted Answer

Pepsin

Answer

Lipase

Answer

Amylase

Answer

Catalase

Question 35

What is the main difference between exoenzymes and endoenzymes?

Accepted Answer

Exoenzymes function outside the cell, while endoenzymes function within the cell.

Answer

Exoenzymes are larger than endoenzymes.

Answer

Endoenzymes are more specific than exoenzymes.

Question 36

Which of the following techniques can be employed to measure enzyme activity?

Accepted Answer

Spectrophotometry (by monitoring the change in absorbance over time).

Answer

Chromatography

Answer

Atomic absorption spectroscopy

Answer

Electrophoresis

Question 37

What is the fundamental significance of enzymes in biological systems?

Accepted Answer

They regulate the rate and specificity of metabolic reactions, facilitating the efficient functioning of cells.

Answer

They provide energy for cells.

Answer

They transport nutrients across cell membranes.

Question 38

Identify the specific region of an enzyme that interacts with the substrate?

Accepted Answer

Active site

Answer

Catalytic site

Answer

Allosteric site

Question 39

Which value represents the substrate concentration at which an enzyme is operating at half of its maximum velocity?

Accepted Answer

Michaelis-Menten constant (Km)

Answer

Turnover number (kcat)

Answer

Catalytic efficiency (kcat/Km)

Question 40

In competitive enzyme inhibition, what type of binding occurs?

Accepted Answer

Inhibitor binds to the active site

Answer

Inhibitor binds to an allosteric site

Answer

Inhibitor binds to the substrate

Question 41

Which enzyme listed below is regulated by allosteric interactions?

Accepted Answer

Aspartate transcarbamoylase

Answer

Lipase

Answer

Catalase

Answer

Hexokinase

Question 42

What is the primary function of coenzymes in enzyme-catalyzed reactions?

Accepted Answer

Provide specific chemical groups or electrons

Answer

Increase the rate of the reaction

Answer

Decrease the activation energy of the reaction

Question 43

Identify the enzyme responsible for breaking down proteins:

Accepted Answer

Trypsin

Answer

Lipase

Answer

Amylase

Answer

Catalase

Question 44

Which of the following accurately describes the nature of enzymes?

Accepted Answer

Enzymes are proteins that act as catalysts in biochemical reactions.

Answer

Enzymes are consumed in the reaction they catalyze.

Answer

Enzymes increase the activation energy of a reaction.

Answer

Enzymes are non-specific and can catalyze any reaction.

Question 45

The active site of an enzyme is:

Accepted Answer

A specific region of the enzyme that binds to and facilitates the conversion of the substrate.

Answer

The entire surface of the enzyme.

Answer

A non-polar region of the enzyme.

Question 46

The optimal rate of an enzyme-catalyzed reaction occurs when:

Accepted Answer

The enzyme is saturated with substrate and environmental conditions are within the optimum range.

Answer

pH is far from the optimum.

Answer

Temperature is below the optimum.

Answer

Substrate concentration is low.

Question 47

Which type of enzyme inhibition occurs when an inhibitor binds to the active site of the enzyme, competing with the substrate for binding?

Accepted Answer

Competitive inhibition

Answer

Uncompetitive inhibition

Answer

Mixed inhibition

Answer

Non-competitive inhibition

Question 48

An example of a cofactor for an enzyme is:

Accepted Answer

A non-protein molecule or metal ion required for enzyme activity.

Answer

Amino acid

Answer

Glucose

Answer

Water

Question 49

Proteolytic enzymes primarily function to:

Accepted Answer

Catalyze the hydrolysis of peptide bonds in proteins.

Answer

Regulate gene expression.

Answer

Transport oxygen.

Answer

Synthesize carbohydrates.

Question 50

Which of the following medical conditions is caused by a deficiency in a specific enzyme?

Accepted Answer

Phenylketonuria (PKU)

Answer

Diabetes

Answer

Cancer

Answer

Cystic fibrosis

Question 51

The process by which cells synthesize enzymes is known as:

Accepted Answer

Translation

Answer

Respiration

Answer

Replication

Answer

Transcription

Question 52

Which of the following statements about enzymes is accurate?

Accepted Answer

Enzymes can be reused multiple times in different reactions.

Answer

Enzymes are not affected by temperature or pH.

Answer

Enzymes are specific for only one type of substrate.