1. Energy and Chemical Reactions

2. Energy is defined as the ability to do work or cause change
Energy is defined as the ability to do work or cause change. Energy can be converted from one form to another, but NEVER be lost or destroyed.

3. Basics of Chemical Reactions
Reactants are found on the left side of the arrow, while products are on the right side.
Reactions must be balanced, or have the same number of each type of atom on both sides.
Two direction arrows, mean the reaction can go backward and forward.
Reactants Products
6CO2 + 6H2O + light C6H12O6 + O2

4. Energy and Reactions
Chemical reactions in your body release energy for use by your cells.
If energy is released the reaction is exergonic (“exo” “thermic”).
out heat
If energy is absorbed the reaction is endergonic (“endo” “thermic”).
in heat
exothermic vs. endothermic (blah)

5. Activation Energy & Catalysts
For most chemical reactions to begin, energy must be added (activation energy).
Catalysts are chemicals that reduce the amount of energy you need to start the reaction. Catalysts in living organisms are called enzymes.
Catalysts LOWER the amount of energy needed to start a reaction.

7. Temperature has a major impact on reaction rate.
As temperature increases, collisions between substrates and active sites occur more frequently as molecules move faster.
BUT…at some point thermal agitation (heat) begins to break the bonds and destroys the enzyme.
Each enzyme has an optimal temperature.

8. Because pH also influences shape and therefore reaction rate, each enzyme has an optimal pH too.
This falls between pH for most enzymes.
However, digestive enzymes in the stomach are designed to work best at pH 2 while those in the intestine are optimal at pH 8.

9. “Carbon Compounds” are made of monomers that connect to form polymers during dehydration synthesis.
There are four molecules of life that are carbon compounds:
lipids (ie. triglycerides, phospholipids)
carbohydrates (ie. glucose, starch)
proteins (ie. enzymes)
nucleic acids (ie. DNA, RNA)
Each is made of a monomer that must connect to other monomers to form larger carbon compounds.
monomer + monomer = polymer (macromolecules of life)

10. carbon compound monomer elements example of polymer
carbohydrate
monosaccharide
C, H, O
sucrose, fructose, starch
lipid
fatty acid
triglyceride, phospholipid, wax, steroids
protein
amino acid
C, H, O, N
enzymes, silk, collagen
nucleic acid
nucleotide
DNA, RNA

11. nucleic acid (monomer)
DNA
nucleic acid (monomer)
LIPID
fatty acid (monomer)
PROTEIN
amino acid (monomer)

12. Dehydration Synthesis & Hydrolysis
All monomers are combined during dehydration reactions (dehydration = loss of water).
As the monomers combine, they give off an OH- and a H+ (collectively a molecule of water).
If monomers have to separate they need a molecule of water to split up again (hydrolysis).
Do you remember me??!!
CARBOHYDRATE
monosaccharide (monomer)
COVALENT BOND forms