1. Unit 2 Objective A
Part 1 Notes
Chemical Reactions

2. A chemical reaction is one or more substances are chemically changed into one or more new substances

3. A + B  C
Reactant – substances you have before the chemical reaction takes place
Product – substances you have after the chemical reaction takes place
Substance A and B are reactants – two separate substances
After the chemical reaction A and B combine to make a totally new substance -- substance C
The chemical reaction occurs where the arrow is
Example

4. The minimum amount of energy required to start a chemical reaction
Particles must collide fast enough and hard enough to break/form chemical bonds
Particles must have enough energy to start the chemical reaction
Activation Energy

5. A molecule, either protein or RNA, that acts as a catalyst in biochemical reactions
A substance
Usually used in small amounts
Increases the rate of a reaction
Without being consumed in the process
Catalyst makes the reaction go
Swift kick in the pants gets the cat moving
Enzymes

6. Enzyme Speed up reactions Holds the molecules close together
Holds the molecules in the correct orientation
Lowers the activation energy
Makes reactions happen quicker and more efficient
Enzyme

7. Enzyme Activity Active Site Substrates
Place on the enzyme that the reaction takes place
Substrates
Reactants that bind to the enzyme before the reaction takes place
Shape of the active site determines which substrates will bind to it
Enzyme Activity

8. Enzyme Activity How it works…
Substrates (reactants) bind to the enzyme’s active site
They fit in a very specific way
Once the substrates are positioned, the enzyme changes slightly
This forces the substrates to bind to each other
The two substrates are now one product
The enzyme then releases the product
The enzyme is not changed
Can be used again

9. Enzyme Activity Enzyme Enzyme Enzyme + 1 Substrate
Enzyme + 2 Substrates
Enzyme squishes 2 Substrates
Enzyme + 1 Product
Enzyme releases Product
Enzyme ready to start again
Enzyme
Enzyme + 1 Substrate
Enzyme breaks 1 Substrate
Enzyme + 2 Products
Enzyme releases Products
Enzyme ready to start again
Enzyme Activity

10. Enzyme Cartoon

14. Enzyme Activity

15. Enzyme Conditions What can stop an enzyme from working? Why?
Temperature pH
Why?
Temperature or pH can make the enzyme change shape
What happens if the enzyme changes shape?
Enzyme Conditions

17. Protein & Heat

18. Metabolism Definition
Sum of all chemical processes in an organism that sustains life
Most of the energy for metabolism comes from the food we eat
The food enters our bodies in is broken down in a series of complex steps
Metabolism

19. Metabolism Enzymes help control those steps
Enzymes are needed to kick start the reactions
They LOWER the activation energy
What is activation energy?
Once the reactions start…
Enzymes help control the rest of the reactions
Metabolism