Enzymes Lab

Question 1

ENZYMES

Answer 1

are globular proteins that catalyze reactions without being consumed themselves

Question 2

Why are enzymes essential to life

Answer 2

Because they allow chemical reactions to occur rapidly and efficiently without having to increase the temperature in the system

Question 3

Each reaction is catalyzed by

Answer 3

its own unique/ specific enzyme

Question 4

SUBSTRATE

Answer 4

is a REACTANT acted upon by an enzyme is called the SUBSTRATE of that enzyme.

Question 5

What does the activity or specific function of an enzyme dependent on

Answer 5

it depend on its 3D shape ( tertiary structure)

Question 6

Generally, How is the name of an enzyme formed

Answer 6

by addidding “ ase” to the name of its substrate

Question 7

ACTIVE SITES

Answer 7

An enzyme molecule contains one more active sites where the SUBSTRATE fits

Question 8

DENATURED

Answer 8

The shape of the enzyme is altered- it no longer is functional

Question 9

EQUATION OF ENZYMATIC REACTIONS

Answer 9

ENZYME + SUBSTRATE ENZYME SUBSTRATE COMPLEX —–> ENZYME + PRODUCT

Question 10

The variable that remains unchanged in a enzymatic ration is

Answer 10

THE ENZYME

Question 11

What happens to the enzyme at the end of a reaction

Answer 11

The product is released and the enzyme returns to it original shape

Question 12

Since all enzymes speed up the conversion of some substances(SUBSTRATE) into a product. How we study the activity of the enzyme

Answer 12

by detecting production of the product ( since only THAT enzyme can cause THAT PRODUCT to be produced

Question 13

Why do some plants and vegetables turn burn if peeled or sliced

Answer 13

It is due to the formation of a class of compounds called QUINONES by the damaged plant.

Question 14

The purpose of QUINONES in potatoes ( for example)

Answer 14

They protect the interior of the potato from invasion by soil microorganisms if the skin of the potato is damaged.

Molecules of quinones collect in the area of the damage and form a brown patch that

1. seals the break
2. is toxic to microorganisms

Question 15

How does QUINONES protect the plant

Answer 15

Molecules of quinones collect in the area of the damage and form a brown patch that

1. seals the break
2. is toxic to microorganisms

Question 16

High concentration of QUINONES is also toxic to plant cells. What mechanism do plants have that make quinone only after the plant skin is damaged.

Answer 16

In addition to cellulose the cell walls also contain CATECHOL

Question 17

in its chemically reduced form ( gained electron) what does CATECHOL look like

Answer 17

It is colorless

Question 18

What happens to CATECHOL in the presence of oxygen

Answer 18

It will oxidize to QUINONE

Question 19

What is the purpose of POLYPHENOL OXIDASE (PPO)

Answer 19

It is an enzyme that catalyses the oxidization of CATECHOL to QUINONES

Question 20

How does PPO work

Answer 20

1. In an undamaged potato PPO remains inside the cells (in the cytoplasm) with the CATECHOL outside.
2. When the potato cells are damaged the cytoplasm leaks out, allowing the PPO to come in contact with the CATECHOL on the outside and catalyze its conversion to QUINONE

Question 21

What is the equation for the QUINONE PRODUCT

Answer 21

PPO( enzyme) + CATECHOL( substrate) ENZYME- SUBSTRATE COMPLEX —> PPO (enzyme) + QUINONE ( product/ brown)

Question 22

How can the activity of any enzyme be measured

Answer 22

by detecting the product of the reaction catalyzed by the enzyme

Question 23

QUINONE is a yellow/ brown liquid, its formation indicates

Answer 23

a reaction has occurred. PPO catalyzed CATECHOl to produce QUINONE

Question 24

Why is QUINONE in its entirety darker than its individual molecules that are a faint copper colored molecule

Answer 24

A solution of QUINONE is proportional to its concentration. The darker the solution, the more product present

Question 25

In the experiment why are the potatoes blended

Answer 25

to open up lots of potato cells

Question 26

Why is the blended potato poured through 4 layers of cheese cloth

Answer 26

To remove most of the starch

Question 27

The extract turns brown why

Answer 27

1. once the cells are broken the PPO comes in contact with the CATECHOL and become QUINONE a brown color.
2. The CATECHOL is used up in the solution to make QUINONE but soon after this product is made PPO IS free to catalyze waiting for more CATECHOL

Question 28

Why does increasing the amount of PPO not increase the rate of the reaction

Answer 28

There are specific amounts of active sites per substrate. Adding more PPO will not make a difference unless more substrate is added