2.3 Exploring enzymes

Question 1

What are enzymes?

Answer 1

Enzymes are protein catalysts that speed up reactions within cells without being used up by the reactions themselves

Question 2

What are the naturally*-occurring micro organisms enzymes?

Answer 2

Bacteria and yeasts

Question 3

Why enzymes are used for baking, cheese-making and production of juice?

Answer 3

Because it improves their texture appearance, and nutritional value to give them desirable flavors and aromas.

Question 4

What are enzymes composed of?

Answer 4

Are proteins
amino acids that arranged in tertiary or quaternary structures that have complex conformations (shapes)

Question 5

How do enzymes function?

Answer 5

Enzymes can be used to join two molecules or break one molecule into two parts

Question 6

What does maltase do?

Answer 6

hydrolyzes breaks down maltose into glucose

Question 7

What does sucrase mean?

Answer 7

hydrolyzes breaks down sucrose into glucose and fructose monomers n

Question 8

What are enzymes specific for?

Answer 8

Enzymes are specific to a particular substrate (reactant)

Question 9

In order for a reaction to occur, the reactions have to overcome

Answer 9

the activation energy (Ea) barrier

Question 10

What is the activation energy?

Answer 10

Is the amount of energy that must be available in order for a reaction to occur.

Question 11

How does the structure of enzymes allow them to lower the activation energy of reactions and increase the speed chemical reaction?

Answer 11

Enzymes lower the activation energy required for the reaction to occur by attaching to the reactants and positioning them so that they are in the optimal orientation to break or make chemical bonds between them.

Question 12

When reactants begin to interact with enzymes they are called

Answer 12

substrates

Question 13

The enzyme and its attached substrate form a structured called

Answer 13

enzyme-substrate complex

Question 14

What happens when the substrate begins to attach?

Answer 14

The active site changes shape slightly to hold on to the substrate

Question 15

Enzymes decrease the energy of activation by

Answer 15

stretching and bending chemical bonds that need to break during the reaction.

Question 16

Coenzymes work by:

Answer 16

moving molecules from one enzyme to another.

Question 17

Many coenzymes are derived from

Answer 17

vitamins

Question 18

The coenzyme NAD- IS A DERVITIVE OF

Answer 18

vitamin B3 (niacin)

Question 19

What does pepsin do>

Answer 19

It breaks down proteins into smaller fragments called peptides so they can be broken down further in the small intestine

Question 20

What is one critical enzyme in respiration?

Answer 20

cytochrome c oxidase

Question 21

What does cytochrome c oxidase do?

Answer 21

Helps to combine the highly reactive waste oxygen molecules produced during this process with hydrogen to form water

Question 22

The enzyme acetylcholinesterase breaks

Answer 22

acetylcholine which is a natural transmitter

Question 23

In bread making amylase is used to break down

Answer 23

flour starch to simple sugars which are converted by yeasts to alcohol and carbon dioxide(which makes the bread rise)

Question 24

What are some benefits of industry enzymes?

Answer 24

1. Replaces synthetic chemical which lower the amount of waste energy to produce food product
2. Pectinase is used to produce clear apple juice
3. Provides specific action that allows very specialized food products to be produced efficiently

Question 25

Advantages of Cellulosic Ethanol

Answer 25

Would not compete with food production since its produced from waste

Question 26

Disadvantages of Cellulosic Ethanol

Answer 26

expensive because of process of extracting it

Question 27

What does lipase enzymes do?

Answer 27

breaks down triglyceride into glycerol and fatty acids

Question 28

Enzymes are regulated using the following methods:

Answer 28

1. Enzyme inhibition: Competitive and non-competitive
2. Feedback inhibition

Question 29

Most enzymes with more than one subunit contain more than one active site called the

Answer 29

allosteric site

Question 30

The allosteric site is a place on an enzyme:

Answer 30

that will not bind substrates that bind to the active site
that will bind to other specific molecules that will change the shape of the enzyme and influence its ability to be active or not.

Question 31

The allosteric site is involved in turning the enzyme

Answer 31

“on” and “off”

Question 32

What is a competitive enzyme>

Answer 32

If the enzyme activation or inhibition happens on an active site its classified as competitive.

Question 33

What is a non competitive enzyme?

Answer 33

If the enzyme activation or inhibition happens as a result of changes on the allosteric site its classified as non-competitive

Question 34

What is the structure of competitive inhibitors

Answer 34

are molecules that are so similar in shape to an enzyme substate that they can bind to active site and block the normal substrate binding

Question 35

What is the function of competitive inhibitors

Answer 35

Once the inhibitor has attached to the active site the enzyme is unable to catalyze any reactions at that site

Question 36

Allosteric (or non-competitive) activators and inhibitors are molecules that bind to the

Answer 36

allosteric site not the active site

Question 37

Allosteric (or non-competitive) activators and inhibitors are molecules that bind to the

Answer 37

allosteric site not the active site

Question 38

Enzymes can oscillate in shape between the “on” and “off” conformation.
They can be temporarily locked into the “on” or “off” conformation by interacting with other molecules called

Answer 38

allosteric activators and inhibitors

Question 39

How is hydrogen peroxide (H2O2) produced?

Answer 39

product of some cell processes and since its toxic to cells it must be inactivated immediately

Question 40

This breakdown of hydrogen peroxide equation is:

Answer 40

2H2O2 –< 2H2O + O2

Question 41

which enzyme is invloved in the breaking down of hydrogen peroxide

Answer 41

catalse