Chapter 3: Enzymes

Question 1

What is the role of enzymes in biochemical pathways?

Answer 1

Enzymes act as catalysts, speeding up chemical reactions in important biochemical pathways.

Question 2

What percentage of the global population is estimated to have a reduced ability to digest lactose?

Answer 2

Approximately 65% of the global population.

Question 3

What are the key factors affecting enzyme activity

Answer 3

Temperature, pH, and enzyme inhibitors

Question 4

How do enzymes influence the complex chemical reactions of photosynthesis and cellular respiration?

Answer 4

Enzymes catalyze these reactions

Question 5

What is the definition of an enzyme?

Answer 5

An organic molecule, typically a protein, that catalyzes specific reactions

Question 6

What happens to enzymes after catalyzing a reaction?

Answer 6

Enzymes remain unchanged and can catalyze future reactions; they are reusable

Question 7

What is the active site of an enzyme?

Answer 7

The area to which the substrate binds, allowing the reaction to occur

Question 8

How do enzymes lower the activation energy of reactions?

Answer 8

Enzymes bring reactants closer to the state needed for the reaction, reducing the size of the activation energy hurdle

Question 9

Why does lactose intolerance occur?

Answer 9

It is a result of an enzyme deficiency, specifically a decrease in lactase levels as individuals age

Question 10

How is lactose broken down in individuals with lactose intolerance?

Answer 10

Without lactase, lactose is broken down by probiotic bacteria, producing gas and causing symptoms like bloating and diarrhea

Question 11

What is a catabolic reaction, and what does it involve?

Answer 11

Catabolic reactions break down large molecules into smaller ones, releasing energy in the process. Examples include digestion and cellular respiration.

EXERGONIC - releases energy

Question 12

2. Define an anabolic reaction and provide examples.

Answer 12

Anabolic reactions build larger molecules from smaller ones, requiring energy. Examples include protein synthesis and photosynthesis.

ENDOGONIC - requires energy

Question 13

3. What is activation energy in a chemical reaction?

Answer 13

coActivation energy is the minimum energy needed for a chemical reaction to occur.

Question 14

Describe the process of enzyme action and the role of active sites.

Answer 14

Enzymes, proteins with active sites, catalyze reactions by attracting substrates, inducing stress for bond-breaking, and forming products. Active sites are crucial for enzyme specificity.

Question 15

Explain the role of coenzymes and cofactors in enzyme-catalyzed reactions. Provide examples.

Answer 15

Coenzymes (e.g., ATP, NADH) and cofactors (inorganic/organic) assist enzymes by transferring energy. Examples include metallic ions and vitamins.

Question 16

What is the significance of pH and temperature in enzyme activity?

Answer 16

Enzymes function optimally within specific pH and temperature ranges. Extremes can denature enzymes, affecting their efficiency.

Question 17

7. How does substrate concentration influence enzyme reaction rates?

Answer 17

Increasing substrate concentration enhances reaction rates until saturation, where all active sites are occupied.

Question 18

Differentiate between reversible and irreversible enzyme inhibition.

Answer 18

Reversible inhibition is temporary (competitive/non-competitive), while irreversible inhibition permanently deactivates enzymes. (form unbrekable covalent bonds)

Question 19

Explain the lock and key model and induced fit model of enzyme-substrate interaction.

Answer 19

The lock and key model symbolize specific substrate-enzyme binding, while the induced fit model involves shape changes for better interaction.

Question 20

What are the factors affecting enzyme activity?

Answer 20

pH, temperature, enzyme concentration, substrate concentration, and inhibition are factors influencing enzyme activity. Each factor plays a critical role in enzyme function.