1. Chemistry in Biology * see THE PERIODIC TABLE of ELEMENTS *
Element – a pure substance that can’t be broken down into a simpler form of matter
* see THE PERIODIC TABLE of ELEMENTS *
ATOM -The simplest particle of an element that retains the properties of that element
Sub-atomic particle
Charge
Proton +1
Neutron
Electron -1
In Nucleus →

3. Elements Found in Living Things
Carbon (C) %
Hydrogen (H) 9.5%
Oxygen (O) 65%
Nitrogen (N) 3.3%
Phosphorus (P) 1.0%
Sulfur (S) 0.3%
Others… K, Ca, Na

4. BONDING
Compound – A substance containing atoms of 2 or more elements bonded together
Covalent Bond → electrons are shared
Ionic Bond → electrons are transferred

5. COVALENT BOND

6. IONIC BOND

8. WATER
Remember:
Electrons are shared in a covalent bond
*** But not necessarily shared evenly
A molecule is said to be POLAR if it has an uneven charge distribution like this
Characteristics of POLAR Compounds:
Hydrogen Bonding
Attraction (“polar likes polar”)
Temperature Moderation
Water’s Surface Tension

9. SOLUTIONS A solution is saturated when no more solute can dissolve
A mixture of 2 or more substances
Uniformly distributed
SOLUTE dissolved into a SOLVENT
CONCENTRATION – a measurement of the amount of solute dissolved in a fixed amount of solvent
A solution is saturated when no more solute can dissolve
AQUEOUS SOLUTION – a solution in which water is the solvent
*** THINK ABOUT LIVING SYSTEMS ***
(your body cells!)

10. Potential of Hydrogen A water molecule can break up (dissociate)
2 H20 ↔ H30+ + OH-
(Hydronium ion) (hydroxide ion)
ACID SOLUTION – hydronium ions outnumber hydroxide ions
BASE SOLUTION – hydroxide ions outnumber hydronium ions
(a.k.a. alkaline solution)
pH scale
acidic neutral basic
]____________________________________________[
stomach acid Urine Water Intestinal Fluid

11. Organic Compounds Carbon can make 4 bonds
Organic compounds have a carbon backbone
STRUCTURE:
Monomer – single, simple structural unit
Polymer – repeated, linked chain of monomers
Condensation Reaction –
Forms polymers; water molecule is given off in the process
Hydrolysis Reaction –
Breaks polymers; water molecule is used in the process

16. GLUCOSE

17. Condensation (dehydration synthesis)

18. Hydrolysis

19. ENERGY TRANSFER Reactants → Products
BUT: Not all reactions were created equal
Exergonic/Exothermic –
A chemical reaction that results in a release of energy
Endergonic/Endothermic –
A chemical reaction that results in an absorption of energy
Activation Energy -
The energy needed to start a reaction

20. CATALYST -
A substance that reduces the activation energy of a reaction
ENZYME -
Acts as a catalyst in a living system
Usually a protein

21. ENERGY CURRENCY Making of a bond (~) in ATP
The energy currency for the
cell is a molecule called …
Adenosine Triphosphate (ATP)
A = Adenosine ATP = A ~ P ~ P ~ P
P = Phosphate ADP = A ~ P ~ P
~ = chemical bond AMP = A ~ P
Breaking of a bond (~) in ATP releases energy (EXERGONIC)
A~P~P~P → A~P~P + P + ENERGY
Making of a bond (~) in ATP
“bottles up” energy for later use
(requires energy input)
A~P~P + P + ENERGY → A~P~P~P