1.7- ENZYME ACTION

Question 1

What type of protein are enzymes?

Answer 1

globular proteins

Question 2

What do enzymes act like?

Answer 2

act as catalysts

Question 3

What do catalysts do?

Answer 3

alter rate of chemical reaction without undergoing permanent changes themselves

Question 4

Why are enzymes effective in small amounts?

Answer 4

can be used repeatedly

Question 5

What do enzymes NOT do?

Answer 5

make reactions happen

Question 6

What DO enzymes do?

Answer 6

speed up reactions that already occur

Question 7

By what factor can enzymes sometimes increase a reaction by?

Answer 7

many millions

Question 8

What must the substrates collide with?

Answer 8

sufficient energy

Question 9

Why must the substrates collide with sufficient energy?

Answer 9

to alter the arrangement of their atoms to form products

Question 10

What must the free energy of the products be like in comparison to the substrates?

Answer 10

free energy must be less than that of the substrates

Question 11

What do many reactions require to start?

Answer 11

an initial amount of energy

Question 12

What is the minimum amount of energy needed to activate a reaction called?

Answer 12

activation energy

Question 13

What must initially be overcome before the reaction can proceed?

Answer 13

an activation energy level, like an energy hill or barrier

Question 14

How do enzymes work?

Answer 14

work by lowering the activation energy level

Question 15

As enzymes lower the activation energy what does this mean?

Answer 15

allow reactions to take place at a lower temperature than normal

Question 16

As the reactions are allowed to happen at a lower temperature, what does this mean?

Answer 16

enables some metabolic processes to occur rapidly at human body temp. , 37 degrees Celsius

Question 17

How is 37 degrees Celsius in terms of chemical reactions?

Answer 17

relatively low in terms of chemical reactions

Question 18

What would happen to life without enzymes?

Answer 18

reactions would proceed too slow to sustain life as we know it

Question 19

How are enzymes globular proteins?

Answer 19

have a specific 3D shape that is result of sequence of amino acids (primary structure)

Question 20

What is the name of the specific region of the enzyme that is functional?

Answer 20

active site

Question 21

What is the active site made up of?

Answer 21

relatively small number of amino acids

Question 22

What does the active site form?

Answer 22

a small depression within the much larger enzyme molecule

Question 23

What is the name of the molecule on which the enzyme acts on?

Answer 23

substrate

Question 24

Where does the substrate fit into?

Answer 24

fits neatly into the depression

Question 25

What is formed when the substrate fits into the active site of the enzyme?

Answer 25

enzyme-substrate complex

Question 26

How is the substrate molecule held within the active site?

Answer 26

by bonds that temporarily form between certain amino acids of the active site and groups on the substrate molecule

Question 27

How do scientists often try to explain their observations?

Answer 27

by producing a representation of how something works

Question 28

What is the representations of how something works called?

Answer 28

scientific model

Question 29

What is an example of a scientific model?

Answer 29

physical models used to explain enzyme action

Question 30

What does the induced fit model of enzyme action proposes?

Answer 30

that the active site forms as the enzyme and substrate interact

Question 31

What does the proximity of the substrate lead to?

Answer 31

a change in the enzyme that forms the functional active site

Question 32

Why does the proximity of the substrate cause a change?

Answer 32

as there’s a change in the environment of the enzyme

Question 33

In other words what can the enzymes said to be like?

Answer 33

the enzyme is flexible and can mould itself around the substrate

Question 34

What happens as an enzyme changes its shape?

Answer 34

enzyme puts a strain on the substrate molecule

Question 35

What does the strain exerted by the enzyme do?

Answer 35

distorts a particular bond or bonds in the substrate molecule

Question 36

As bonds are distorted due to the strain, what happens?

Answer 36

lowers the activation energy needed to break the bond

Question 37

What is any change in an enzyme’s environment likely to do?

Answer 37

change its shape

Question 38

Why does the very act of an enzyme colliding with a substrate cause it to change shape?

Answer 38

as it is a change in environment of the enzyme- induced fit