1. Chemical Reactions
A chemical reaction breaks down some substances and builds other substances
2H2 + O > 2H2O
Chemical reactions can occur when reactants collide with enough energy to react
The amount of energy needed for a particular reaction to occur is called activation energy
Some reactions must absorb energy to start, often this is in the form of heat
Some reactions give off energy in the form of heat or light
Biochemical reactions allow organisms to:
Grow Develop
Reproduce Adapt
Reactants
Products

2. Chemical Reaction
Certain conditions can affect the rate at which a chemical reaction will occur
Temperature – gaining or losing heat energy
pH – most organisms need to be kept in a small range of acidity for reactions to properly occur
Buffers within an organism regulate pH so homeostasis is maintained
A small change in pH can disrupt cell processes
Catalysts – a substance that changes the rate of reaction or allows the reaction to occur at a lower temperature
Catalysts are not consumed or altered in a reaction, can be used over and over
Enzymes are catalysts in living organisms

3. Energy and Enzymes Enzymes are made up of proteins
Enzymes are a type of catalyst: a material that lowers the activation energy required for a reaction to occur
Enzymes speed up chemical reactions that otherwise would occur too slowly at the body’s temperature
Reactions are able to occur at lower temperatures

4. Enzyme Functions Functions in the body: Help with digestion of food
Help with energy storage and release
Burning glucose
Help with molecule synthesis
Building proteins and fats

5. Enzyme Names Enzymes will often end in the suffix –ase
The beginning of the name often tells you the substrate of the enzyme
Substrate: what an enzyme acts upon
Examples:
Amylase breaks down amylose (a component of starch)
Lactase breaks down lactose (a sugar in dairy products)
Lactose intolerant people lack the enzyme lactase

6. Enzyme Action Enzymes act on a specific substrate
Fit like a lock and key
Substrate fits at the active site
Enzyme-substrate complex
The product is released from the enzyme
Enzyme is back to its original shape and ready to act again

7. Factors that Affect Enzyme Activity
Temperature
Each type of enzyme has a temperature range at which they like to work. Enzyme activity increases as the environment reaches that ideal temperature and slows outside of that range. pH
As with temperature, there is a specific pH range at which an enzyme will work
At extreme an temperature or pH, an enzyme can denature (change shape and become ineffective)

8. Factors that Affect Enzyme Activity
Enzyme Concentration
If the amount of substrate stays the same, the rate of reaction will increase if the enzyme concentration increases
Reaction rate will drop if it runs out of substrate
Substrate Concentration
If the amount of enzyme stays the same, the rate of reaction will increase if the substrate concentration increases
Reaction rate will level off when all of the enzymes are working
Constant enzyme concentration

9. ATP ATP stands for adenosine triphosphate
ATP is the molecule that supplies energy that can be used quickly and easily by cells
ATP could be used for many things:
Contracting muscles
Transmitting signals
Move flagella
Moving materials in the cell

10. ATP Structure ATP (adenosine triphosphate) is made up of three parts:
A nitrogen base (adenine)
A sugar (ribose)
Three phosphate groups that are held together with high energy bonds

11. ATP  ADP
ATP releases energy by losing a phosphate group and becoming ADP
adenosine triphosphate becomes adenosine diphosphate
When it transfers a phosphate, it transfers energy
This energy drives the cell’s metabolism.
ADP can later bind with another phosphate and start all over again.

12. ATP  ADP
To supply cells with energy, the high energy ATP bond is broken. ADP is formed and energy is released.
ATP  ADP + Phosphate + Energy
Energy is used (and stored) by reattaching a phosphate group to ADP forming ATP to be used later.
ADP + Phosphate + Energy  ATP
Less energy is used to make ATP than is released when it is broken