Molecule: A Precise arrangement of atoms
– May be composed of 2 or more atoms of the
same element or of different elements
– Ex: O2
•Compounds: A collection of molecules
Bonds: Molecules joined by bonds
Ionic: Electrons transferred
Covalent: 2 or more electrons are shared.
Covers more than 75% of Earth’s surface
Unique Property*** there is an uneven
distribution of electrons, slightly charged on
one end => Polarity
– strong attraction among molecules
– The substance that – the substance
does the dissolving dissolved.
Acids and Bases
Acids are chemical Bases are chemical
compounds that compounds that attract
release hydrogen ions hydrogen atoms when
(H+) when placed in they are placed in
A base solution results
HCl --> H+ + Cl- as hydroxyl ( -OH )
NaOH --> Na + + OH-
90 Naturally Occurring Elements
11 Elements common in living organisms
96.3% of the Human body composed of
The main 4: Carbohydrates, lipids,
proteins, and nucleic acids.
Carbon! Strong, stable covalent bonds
– Simplest compound= methane CH4 C
– Can form large chains.
Molecules composed of
carbon, hydrogen and oxygen.
– 1:2:1 ratio
Sugars ( glucose, sucrose,
Starches (glycogen, amylase)
Chitin (exoskeleton of insects)
Cellulose (cell walls of plants)
Composition and Structure:
1) 1:2:1 ratio (C:H:O)
2) CH2O = empirical formula (shows ratio)
such as C6H12O6 (actual molecular formula)
3) In bodies: found in a ring form.
Must Memorize structure of glucose!
Suggestion: Draw skeleton, put in H’s, Put on OH’s
And continued more...
5) Monosaccharide = 1 ring sugar (glucose)
Disaccharide = 2 ring sugars (sucrose)
Polysaccharide= simple or branched chain(s)
– Monosacc. Monomers --> bond to form
6) Dehydration Synthesis: bonding
together 2 molecules by removing H2O.
– Ex: Glucose + Fructose --> Sucrose + Water
Result= Maltose (disaccharide) which is 2 glucose
units covalently linked.
Energy - breaking down glucose/sugars in a
stepwise fashion releases the energy trapped
in the bonds.
– Energy is captured and used by cells.
Storage of Energy - Complex carbs-like
starches, store energy for later use
– Complex carbs must be broken into simple
sugars by HYDOLYSIS (H2O added).
Structural components/ Protection:
Fibers, chitin, cellulose of cell walls make
tough, hard structures to provide support
(skeleton) and protection.
Fats (butter, lard, meat fats)
Oils ( Veg. Oils-olive oil)
Waxes ( earwax, layer on leaves)
Steroids ( make up hormones-
testosterone, estrogen, cortisone)
Composition and Structure
C, H, O with only a few O
relative to # of C and H
Saturated/ Unsaturated Fat
Notice the double bond.
Triglyceride: bond 2 f.a.’s to
glycerol by dehydration synthesis
*tend to be solid at room temp.
*bad for your arteries
-Need some fats to process fat
soluble vitamins (A,D,E & K)
-Meat and dairy.
*tend to be liquids at room temp.
- mono-unsat. Is believed to be better at
lowering LDL (the bad cholesterol)
-Flax, canola oil, salmon, nuts, seeds.
Energy: breaking C-H bonds
– protection from bumps/abrasions, etc…
– prevent water loss: like the waxes on leaves.
Examples: Proteins are found
in foods such as meat, cheese,
eggs, nuts, beans,etc…
Proteins have 2 primary jobs
1) Structural components of cell
2) Enzymes that control cell
Composition and Structure
Composed of C,H,O,N with
Sulfur (S) and (P) phosphorus
in some side chains.
Proteins are polymers composed of amino
– May be straight chain, folded, or globular.
There are 20 amino acids that build
– 20 a.a have same basic structure but differ only
at the side chain position [R]
group on one end
Always one lone H
R is one of 20
possible side chains
NH2 is the amino
Structure: Primary, Secondary, Tertiary,
20 possible R- amino acids.
Protein Synthesis…take notice of the
peptide bond and the end product of water.
Structural Components of Cell Parts-
– functions like the framework that other
molecule are attached to build cell parts.
– Construct things!
• Bone, cartilage, tendons, ligaments
– Enzymes catalyze the chemical reactions that take place
• Genetic Code: made up of specific amino acid
Source of Energy
– Composed of smaller units called nucleotides
• Each nucleotide contains carbohydrate, a phosphate,
and a nitrogen-containing molecule.
2 types of nucleic acids
– 1. RNA: ribonucleic acid : found in nucleus
and cytoplasm contains uracil
– 2. DNA: deoxyribonucleic acid: found in cell
nucleus. Contains thymine.