1. Chapter 2: The Chemical Basis of Life
Matter is anything that has
mass & takes up space.
Solid
Liquid
Gas
Elements make up all
matter (living and
nonliving).
EX. Carbon, oxygen,
hydrogen

2. Basic Chemistry (carbon, hydrogen, nitrogen, oxygen)
There are only 25 elements that are basic to life.
CHON= Make up 96% human weight
(carbon, hydrogen, nitrogen, oxygen)
The atom is the smallest part of an element.
Made up of:
1) protons (+ charge)
2) neutrons (neutral)
3) electrons (- charge)

3. Basic Chemistry cont.
Atomic Number: the number of protons in the nucleus of atom that makes it unique.
Atomic Mass = # of protons + # of neutrons

4. Basic Chemistry cont.
Isotopes = same # protons, different # of neutrons
Radioactive isotopes release energy in the forms of rays & subatomic particles.
Can harm cells
Damage DNA
Cause cancer
May have beneficial uses:
Sterilize medical equipment
Kill cancer cells

5. Chemistry of Life Bonds:
Ionic: oppositely charged ions are attracted to each other after gaining or losing electrons
Water soluble (ionic bonds break)
Ex. NaCl table salt
Covalent: atoms share valence electrons
Bonds do not break in water; often not water soluble
Ex. C6H12O6 glucose
Polar covalent: atoms share valence electrons unequally
A prerequisite for hydrogen bonds
Hydrogen: partially positive H (part of a polar covalent bond) is weakly attracted to partially negative O, N, or F (part of polar covalent bond)
Ex. H20 water 5

6. Water’s Life Supporting Properties
Water is cohesive & adhesive
Cohesion: water molecules stick together
Hydrogen has partial positive charge
Oxygen has partial negative charge
Oxygen of one H2O molecule attracted to Hydrogen of another molecule
Adhesion: water is attracted to other partially charged substances
Surface Tension: a measure of how difficult it is to stretch or break the surface of a liquid

7. Water’s Life Supporting Properties
Heat: the amount of energy associated with the movement of atoms and molecules
Temperature: measures average speed of molecules
Ice is less dense than liquid water due to the 3-D crystalline bonding pattern
Hydrogen bonds are stable
Atoms are equally spaced apart
Hydrogen bonds in liquid water constantly break & re-form

8. Water’s Life Supporting Properties
Solution: liquid consisting of a uniform mixture of 2 or more substances
Solvent: dissolving agent
Solute: Substance that is dissolved
Aqueous solution: water is the solvent
Water can dissolve ionic compounds & other polar molecules (Ex. NaCl, sugar)

9. Chemistry of Life pH (Power of Hydrogen ions)
Scale from 1 (highest # of H+) to 14 (lowest # of H+)
Low numbers are acids (1-6)
High numbers are bases (8-14)
7 is neutral

10. Chemistry of Life All living things contain carbon.
Organic compounds are substances that contain carbon and make up all living things.
There are four kinds of organic compounds:
1) carbohydrates
2) lipids
3) proteins
4) nucleic acids

11. Organic Compounds Carbohydrates
Sugars & starches
Contain elements C, H, O in a 1:2:1 ratio
C6H12O6 glucose
Energy source for living things
The building blocks of carbohydrates are monosaccharides or single sugars.
Dissacharides are two single sugars bonded together.
Ex. Sucrose (table sugar)= glucose + fructose
Polysaccharides are 3 or more single sugars bonded together.
Ex. Starch, cellulose, glycogen

12. Organic Compounds The building blocks of lipids are fatty acids.
Fats, waxes, and oils
Do not dissolve in water
Made up of C, H, and O but not in a ratio
Store and release energy
Ex. Steroids, phospholipids, chlorophyll
The building blocks
of lipids are fatty
acids.

13. Organic Compounds Proteins
Made up of the elements C, H, O, N, S
Make up hair, skin, nails
The building blocks of proteins are amino acids.
Enzymes are special proteins that speed up chemical reactions.
Ex. Salivary amylase

14. Organic Compounds The building blocks of nucleic acids are
Ex. DNA & RNA
DNA is found in the nucleus of all living cells.
DNA makes up genes which store hereditary information.
The building blocks of
nucleic acids are
nucleotides.
Nucleotides are made up of 3 parts:
1) a base
2) a sugar
3) a phosphate

15. ATP Adenosine triphosphate (ATP) is an energy found in living cells.
Fuel for cells
Used to make proteins & carbohydrates in cell
Energy needed for muscle cells to contract
Energy needed for nerve cells to conduct impulses
ATP stores its energy in the chemical bonds between the phosphate atoms.
Energy is released when bonds are broken.
ATP is made up of a sugar, the base adenine, and 3 phosphate molecules.