Multiple Choice

Question 1

How does an enzyme allow chemical reactions to occur more often than without an enzyme present?

Answer 1

activation energy (the amount of energy needed to begin the reaction) is reduced when an enzyme is present

Question 2

Which component binds to the active site of an enzyme, and why?

Answer 2

A single substrate binds to the enzymes active site, facilitating the conversion of the substrate into product

Question 3

Which component would bind to the regulatory site of the enzyme, and why?

Answer 3

The enzyme’s regulatory site will bind components that will either enhance or decrease the enzymes capacity to facilitate the chemical reaction in order to regulate how often the reaction occurs

Question 4

What happens to the enzymes in the human body at temperatures above 40 degrees?

Answer 4

Prolonged exposure to 40 degrees will see more and more of the enzymes breakdown, compromising the body’s ability the perform chemical reactions

Question 5

Describe the lock and key model.

Answer 5

The enzyme’s active site has a specific shape that accommodates a specific substrate, allowing the substrate to bind to the enzyme to form the enzyme-substrate complex.

Question 6

Describe the induced fit model.

Answer 6

The enzyme’s active site has a similar shape to the specific substrate, and after small changes to the structure of the active site, the enzymes active site accommodates the binding of the specific substrate.

Question 7

Describe a competitive inhibitor that sometimes binds to an enzyme.

Answer 7

A competitive inhibitor has a very similar shape to the substrate, so both the inhibitor and the substrate compete to bind to a specific enzyme’s active site.

Question 8

Describe a non-competitive inhibitor which does not compete with the substrate for the active site.

Answer 8

A non-competitive inhibitor binds to the regulatory site of the enzyme, causing the shape of the active site to change so that the enzyme’s active site can no longer bond the substrate.

Question 9

Describe an irreversible inhibitor.

Answer 9

An irreversible inhibitor forms a covalent bond to part of the active site, with the attachment of the inhibitor creating an irreversible change to the shape of enzyme’s active site, meaning the substrate can not bind to the enzymes active site

Question 10

Why are different enzymes needed for different reactions?

Answer 10

A certain enzyme’s active site can only accomodate the binding of a substrate that has a complementary shape, with this binding event needed to facilitate the conversion of reactant into product

Question 11

Why is it necessary for zymogens to be synthesised in the inactive form?

Answer 11

If the zymogen enzymes were active all the time they would damage the body, instead the zymogen’s are activated only when their function needs to be performed.

Question 12

What do coenzymes provide to help the chemical reaction take place?

Answer 12

The coenzyme provides chemical reactivity (that the apoenzyme does not provide), such as the capacity to engage the substrate in a redox reaction which are often used in metabolism.

Question 13

Is energy required or released in a chemical reaction where ATP is converted to ADP?

Answer 13

Energy is released when ATP is converted into ADP, as ATP loses one of its high energy phosphoanhydride bonds.

Question 14

Is energy required or released in a chemical reaction where ADP is converted to ATP?

Answer 14

Energy is required when ADP is converted into ATP, as ATP gains a high energy phosphoanhydride bond.

Question 15

What is the reduced for of the NAD+ coenzyme?

Answer 15

The reduced form of the coenzyme is NADH, as it contains more hydrogen atoms than NAD+, demonstrating that NADH has undergone a redox reaction.

Question 16

What is the oxidised form of the FAD coenzyme and why?

Answer 16

The oxidised form of the coenzyme is FAD as it contains less hydrogen atoms than FADH2, demonstrating that it has undergone oxidation in a redox reaction.

Question 17

For the FAD / FADH2 coenzyme, which is the electron rich version and why?

Answer 17

FADH2 is the electron rich version as FADH2 contains two extra hydrogen atoms (each contain one electron).

Question 18

What events take place in the digestion part of the bioenergetic pathway?

Answer 18

Complex molecules are broken down into simpler molecules, which are absorbed into the blood where they can be taken up by cells to be further metabolised.

Question 19

What events take place in the acetyl group formation part of the bioenergetic pathway?

Answer 19

Multiple metabolic reactions are used to convert simple compounds that were originally part of either a protein, lipid or carbohydrate into the central metabolite which is required for the Citric Acid Cycle.

Question 20

What events take place in the Citric Acid Cycle part of the bioenergetic pathway?

Answer 20

Oxidised coenzymes are converted to electron rich coenzymes in multiple chemical reactions within this process, with the electron rich coenzymes then taken to the Electron Transport Chain.

Question 21

What events take place in the Electron Transport Chain part of the bioenergetic pathway?

Answer 21

The electron rich coenzymes are needed to begin this process, which connects to a second process that produces a significant amount of ATP.

Question 22

If an individual’s oxygen supply was cut off for five minutes, what affect would this have on the individual?

Answer 22

The individuals cells would begin to die, eventually leading to death of the individual, as ATP generation ceases in the absence of oxygen.