Enzymes

Question 1

What is thermodynamics?

Answer 1

The study of energy and its transformations.

Question 2

What are exergonic reactions?

Answer 2

Energy-releasing reactions.

Question 3

What are endergonic reactions?

Answer 3

Energy-requiring reactions.

Question 4

What does thermodynamics tell us about a reaction?

Answer 4

Whether a reaction can occur, but not how fast it will happen.

Question 5

What is activation energy (Ea)?

Answer 5

The energy needed to start a reaction

Question 6

Why don’t spontaneous reactions always happen quickly?

Answer 6

Because reaching the activation energy is rare.

Question 7

How do enzymes affect activation energy?

Answer 7

Enzymes lower the activation energy needed for reactions.

Question 8

What role do enzymes play in biological systems?

Answer 8

They act as catalysts to speed up reactions without being consumed.

Question 9

Do enzymes change the overall free energy change (ΔG) of a reaction?

Answer 9

No, enzymes do not change the overall free energy change of a reaction.

Question 10

What is enzyme specificity?

Answer 10

The concept that each enzyme catalyzes only particular reactions.

Question 11

What is the induced-fit hypothesis?

Answer 11

The idea that enzymes adjust their shape to bind substrates more precisely.

Question 12

What happens to enzymes after the reaction?

Answer 12

They are released unchanged and ready to catalyze more reactions.

Question 13

What are cofactors?

Answer 13

Non-protein molecules essential for enzyme activity.

Question 14

How do enzymes bring reactants together?

Answer 14

By binding reactants in the right orientation for the reaction.

Question 15

How do enzymes strain reactant bonds?

Answer 15

By putting stress on bonds, making them easier to break.

Question 16

What favorable microenvironments do enzymes create?

Answer 16

Enzymes provide an environment conducive to the reaction.

Question 17

What is ATP’s role in reactions?

Answer 17

ATP typically provides the energy in coupled reactions.

Question 18

What are some factors that influence enzyme activity?

Answer 18

Substrate concentration, molecule interactions, temperature, and pH.

Question 19

How does enzyme concentration affect the reaction rate?

Answer 19

With excess substrate, the reaction rate is proportional to enzyme concentration.

Question 20

What happens to the reaction rate as substrate concentration increases?

Answer 20

The reaction rate increases until enzymes become saturated.

Question 21

What are competitive inhibitors?

Answer 21

Molecules that resemble the substrate and bind to the enzyme’s active site, reducing the reaction rate.

Question 22

Can competitive inhibition be overcome?

Answer 22

Yes, by increasing substrate concentration (if the inhibition is reversible).

Question 23

What are noncompetitive inhibitors?

Answer 23

Molecules that bind to an allosteric site on the enzyme, altering its function without competing with the substrate.

Question 24

How do noncompetitive inhibitors affect enzyme activity?
.

Answer 24

They can either increase or decrease enzyme activity

Question 25

What is feedback inhibition?

Answer 25

A regulatory mechanism where the product of a reaction inhibits the enzyme that produces it.

Question 26

Give an example of feedback inhibition.

Answer 26

The synthesis of isoleucine from threonine, where isoleucine inhibits the first enzyme in the pathway.

Question 27

What is the optimal temperature for enzyme activity?

Answer 27

The temperature at which an enzyme functions most efficiently.

Question 28

What happens to enzyme activity at temperatures above the optimal range?

Answer 28

Enzyme activity declines rapidly as enzymes can denature.

Question 29

How does pH affect enzyme activity?

Answer 29

Each enzyme has an optimal pH, and deviation from this pH can reduce its activity.

Question 30

What can extreme changes in pH do to an enzyme?

Answer 30

They can alter the enzyme's structure and function, reducing its activity.

Question 31

Why is understanding enzyme regulation important?

Answer 31

It is crucial for controlling enzyme activity in biological and industrial processes.

Question 32

What is activation energy?

Answer 32

The minimum amount of energy required for a chemical reaction to occur.

Question 33

What is the active site of an enzyme?

Answer 33

The specific region where substrate molecules bind and undergo a chemical reaction.

Question 34

How do enzymes affect activation energy?

Answer 34

Enzymes lower the activation energy, increasing the reaction rate.

Question 35

What is allosteric regulation?

Answer 35

The regulation of an enzyme's activity through the binding of a regulatory molecule at a site other than the active site, known as the allosteric site.

Question 36

What is an allosteric site?

Answer 36

A specific site on an enzyme, distinct from the active site, where a regulatory molecule can bind, inducing a conformational change in the enzyme.

Question 37

What is a catalyst?

Answer 37

A substance that increases the rate of a chemical reaction without being consumed or permanently altered.

Question 38

What is a coenzyme?

Answer 38

A non-protein organic molecule that binds to an enzyme and is essential for its activity, often acting as a carrier during the enzymatic reaction.

Question 39

What is a cofactor?

Answer 39

A non-protein chemical compound or metallic ion required for an enzyme's activity, assisting in the proper functioning of the enzyme.

Question 40

What is competitive inhibition?

Answer 40

When a molecule similar to the substrate competes for binding at the enzyme's active site, reducing the enzyme's activity.

Question 41

Can competitive inhibition be overcome?

Answer 41

Yes, by increasing the concentration of the substrate.

Question 42

What is an enzyme?

Answer 42

A protein that acts as a biological catalyst, speeding up the rate of a chemical reaction without being consumed.

Question 43

What is feedback inhibition?

Answer 43

A regulatory mechanism where the end product of a metabolic pathway inhibits an enzyme involved in its synthesis, preventing overproduction.

Question 44

What is a substrate?

Answer 44

The specific reactant molecule that an enzyme acts upon during a biochemical reaction.

Question 45

How do enzymes function as catalysts?

Answer 45

By lowering the activation energy required for the reaction to occur.

Question 46

What happens at the enzyme's active site?

Answer 46

The substrate binds, forming an enzyme-substrate complex, and is converted into products.