enzymes

Question 1

enzymes

Answer 1

3-D proteins that act as a biological catalyst

-name are often end with -ase

Question 2

activation energy

Answer 2

energy is needed to start a chemical reaction, usually heat

problem:
- for cells to start reactions they need to put in energy; but temperature increase can coagulate their proteins and cells die!

solution:
-enzymes lower the neccessary energy of activation

Question 3

uncatalyst reaction

Answer 3

requires a higher activation energy than the catalyzed reaction
-no difference in free energy between catalyzed and uncatalyzed reactions

Question 4

substrate

Answer 4

molecule to which the enzyme attaches itself

Question 5

active site

Answer 5

the area of an enzyme that attaches with the substrate molecules

Question 6

enzyme helpers

Answer 6

1. cofactors

2. co-enzymes

Question 7

cofactors

Answer 7

inorganic molecules, atoms or ions that help enzymes bind to substrate molecules
-made from minerals

Question 8

co-enzymes

Answer 8

organic molecules that help enzymes bind to substrate molecules
-made from vitamins

Question 9

factors affecting enzyme activity

Answer 9

1. temperature
2. pH
3. concentration of substrate
4. concentration of enzyme
5. inhibitors

Question 10

temperature

Answer 10

increase temp.= faster reaction

• but high temp can break the enzyme stopping it from working- active site can no longer bind substrate molecules
  
  • can work at an optimum temperature

Question 11

pH

Answer 11

each enzyme works at its optimum pH

• change in acidity or basicity can change enzyme shape
  
  • active site can no longer bind substrate molecules

Question 12

concentration of substrate

Answer 12

enzymes work slowly with low substrate concentration

• usually more substrate increases reaction rate
• when the enzyme is working as fast as it can, it has reach maximum velocity (Vmax) and more substrate will not make it work faster

Question 13

concentration of enzyme

Answer 13

usually the presence of more enzyme will increase the reaction rate, providing there is an unlimited supply of substrate

Question 14

2 types of inhibitors

Answer 14

1. competitive inhibitors

2. non-competitive inhibitors

Question 15

competitive inhibitors

Answer 15

compete with the substrate for the active site on the enzyme.

• if they bond to the enzyme they stop the reaction
  - loosely bound to the active site and can be replaced by the substrate (effect is reversible)

Question 16

non-competitive inhibitors

Answer 16

attaches to the enzyme changing the shape of the active site = the substance cannot bind

• irreversible event
• adding more substrate will not reactivate the enzyme

Question 17

inhibition pathway

Answer 17

enzyme participate in a metabolic pathway where the substrate is modified by a number of enzymes before producing a final product
-as the final product gather together within the cell, it binds to the regulatory site of an enzyme in the path way, changing its shape and thus preventing the substrate from binding

final product is no longer produced until concentration are reduced

Question 18

precursor

Answer 18

store up substrate molecules causes these molecules to attach to the regulatory site of one of the enzymes in a pathway, which improves fit between enzyme and substrate – increases reaction rate