4- Enzymes

Question 1

What is metabolism?

Answer 1

the sum of all chemical reaction within cells and organisms

Question 2

What is an anabolic reaction?

Answer 2

one which builds a molecule or molecules

Question 3

What is a catabolic reaction?

Answer 3

One which breaks down a molecule or molecules

Question 4

Why do organisms need enzymes in their bodies?

Answer 4

To act as catalysts for their metabolic reactions

Question 5

what are some benefits that enzymes provide tov organisms?

Answer 5

Mean the organism requires less energy to function, meaning it needs to consume less food and could maintain a lower body temperature. Would also save time

Question 6

Where do intracellular enzymes act?

Answer 6

Inside cells

Question 7

Where do extracellular enzymes act?

Answer 7

Outside of cells

Question 8

What is the structure of catalyse?

Answer 8

A conjugated globular protein with 4 haem groups in its quaternary structure

Question 9

Is catalyse intracellular or extracellular

Answer 9

Intracellular

Question 10

What is the function of catalyse?

Answer 10

It breaks down toxic hydrogen peroxide into water and oxygen

Question 11

What is the function of amylase?

Answer 11

breaks down starch into maltose

Question 12

Where is amylase present? Is it intra or extracellular?

Answer 12

-mouth and small intestine
-extracellular

Question 13

What is the function of trypsin?

Answer 13

It is a protease, and therefore breaks down proteins into peptides

Question 14

Where does trypsin work? Is it intra or extracellular?

Answer 14

-Small intestine
-Extracellular

Question 15

What is the lock and key hypothesis?

Answer 15

-an are within the tertiary structure of an enzyme which has a shape complementary to the shape of a specific substrate molecule
-this area is called the active site
-when the substrate is bound to the active site an enyme-substrate complex is formed
-the substrate is held in a way by the enzyme that the right atom-groups are close enough to react. The R-groups within the active site will also react with the substrate forming temporary bonds
-these put strain on the bonds within three substrate, which also helps the reaction along

Question 16

What determines the shape of an enzymes active site?

Answer 16

It’s tertiary structure

Question 17

What type of proteins are enzymes?

Answer 17

globular

Question 18

What is the induced fit hypothesis?

Answer 18

-the substrate enters the active site of an enzyme, which os not complementary but a slightly different shape to the substrate
-the active site slightly changes shape to mould around the substrate, this puts pressure on the substrate via its R-groups and causing a reaction
-when the enzyme-substrate complex occurs it puts strain on the bonds and therefore lowers the activation energy

Question 19

What is an enzyme-product complex?

Answer 19

When the substrate reacts and the products are formed (within the lock and key hypothesis)

Question 20

What are enzymes?

Answer 20

-biological catalysts
-globular proteins that interact with substrate molecules causing them to react at much faster rates

Question 21

What are the roles of enzymes in reactions?

Answer 21

-catalyse anabolic reactions which are required for growth
-catalyse catabolic reactions which release energy that is required for majority of living processes
-catalyse digestion to break down larger organic molecules
eg. starch

Question 22

How is startch digested?

Answer 22

1. Startch polymers are partially broken down into maltose by the enzyme amylase (which is produced by salivary glands and pancreas) in the mouth and small intestine
2. Maltose is broken down into glucose by maltase present in the small intestine
3. Glucose is small enough to be absorbed by the cells lining in the digestive system and subsequently absorbed into the bloodstream

Question 23

What must occur for a reaction to take place?

Answer 23

-some or all chemical bonds in reactants must be broken so that new bonds can form
-molecules need to collide in the right orientation
-energy needs to be supplied , activation energy (the highest the activation energy the slower the reaction will be)

Question 24

What the factors that affect enzyme activity?

Answer 24

-temperature
-pH
-enzyme concentration
-substrate concentration

Question 25

However do enzymes lower the activation energy of anabolic reactions?

Answer 25

The tight fit between the two substrates in the enzyme-substrate complex reduces the repulsion between the two molecules, so they bond more easily

Question 26

However do enzymes lower the activation energy of catabolic reactions?

Answer 26

The strain placed on the substrate by its fitting in the active site causes it to break down more easily