• Organic – molecules that have a carbon skeleton and also contain some hydrogen atoms
•Carbon is versatile because can form many bonds allowing for vast array of organic molecules
• Functional groups – groups of atoms attached to the carbon backbone that determine the characteristics and chemical reactivity of the molecule

•Organic molecules are synthesized by linking small organic molecule subunits ( monomers ) together to form a long chain called a polymer
•Monomers are linked together by a condensation reaction (dehydration synthesis)
•Monomers are broken apart by hydrolysis – a water molecule is added to the reaction and broken apart to separate monomers

2
n

•Composed of 3 to 7 carbon atoms – “circle up” into a ring when dissolved in water
•Glucose (C
6
H
12
O
6
) most common monosaccharide in living organisms
•Body’s main source of energy
•Other monosaccharides include fructose, galactose, ribose, and deoxyribose

• Disaccharides – two single sugars linked together
(examples: maltose, sucrose, lactose)
• Polysaccharides – long chains of single sugars
1.
Starch – long term energy (glucose) storage for plants
2.
Glycogen – energy storage (glucose) for animals
3.
Cellulose – structural support for plants (makes up cell walls) a. Highly insoluble b. Bonds btw glucose units are β linkages instead of α linkages c. Animals cannot digest cellulose

• Contain carbon, hydrogen, and oxygen and may contain phosphorus and nitrogen – highly insoluble (hydrophobic)
• Functions:
1. Energy storage molecules
2. Provide insulation
3. Forms waterproof covering
4. Make up the bulk of cell membranes
5. Act as hormones

1. Oils, fats and waxes
• Contain only carbon, hydrogen, and oxygen
• Contain glycerol bonded to 3 fatty acid subunits

2. Phospholipids
• Similar to oil except one fatty acid is replaced with a polar phosphate group – primary component of cell membranes

3. Steroids
• Structurally different from other lipids
• Composed of 4 rings of carbon fused together with various functional groups

• Molecules composed of one or more chains of amino acids
• Functions of proteins:
1. Structure (skin, hair, nails, horns)
2. Movement (muscles)
3. Defense (antibodies)
4. Storage of energy and materials (albumin in egg whites)
5. Transport (hemoglobin to carry O
2
)
6. Signals/hormones (neurotransmitters, protein hormones)

•Building blocks of proteins
•20 different kinds – all have the same fundamental structure, differ based on R group

•R group gives each amino acid it’s distinctive properties (size, water solubility, electrical charge)
•Cysteine has sulfur in it’s R group causing it to form bonds with other cysteines forming disulfide bridges

•Amino acids are linked together by condensation reactions linking the amino group (-NH
2
) of one amino acid to the carboxyl group (-COOH) of the next forming a peptide bond
•Polypeptides vary in length between 3 amino acids to thousands of amino acids

•Primary structure – specific sequence of amino acids coded for by the DNA
(different proteins have different sequences

•Secondary structure – hydrogen bonds cause protein chains to coil or fold ( α helix or β pleated sheet are common structures)

• Tertiary structure – secondary structure folds into a complex, 3-D specific shape
• Caused by:
1. Disulfide bridges between cysteines
2. Cellular environment – whether protein is dissolved in water of cytoplasm or in lipids of membrane (hydrophobic/hydrophilic interactions of amino acids)
3. Polar amino acids will orient themselves to watery environments
4. Non-polar amino acids will orient themselves away from water

•Quaternary structure – proteins that consist of 2 or more independent polypeptide chains held together by hydrogen bonds (ex.
Hemoglobin)

The shape of a protein allows it to perform it’s function
• Exact type, position and number of amino acids with specific R groups determines both the structure (shape) of the protein and it’s biological function
•
If the shape is changed, the protein will NO LONGER function the same way
• Denatured proteins – have lost most of their secondary, tertiary, and quaternary structure (THE SHAPE HAS
CHANGED – protein will no longer function the same way)
1. Causes: a. Extremes in temperature (over 60 o C) b. Extremes in pH c. Excessive radiation d. Electricity e. Certain chemicals

•Proteins that have a nonproteinaceous prosthetic group attached – ex. Hemoglobin contains iron which alters the properties of the protein (increases affinity for O
2
)

Fibrous vs Globular Proteins
• Fibrous proteins – tertiary structure that is a long, much-coiled chain, often insoluble
– Ex. Collagen (skin, bone and tendons) and keratin (hair, horns, nails)
• Globular proteins – tertiary structure is more spherical, usually highly soluble in water
– Ex. enzymes, hormones, insulin

• Long chains of similar but not identical subunits called nucleotides
• Make up the hereditary information (genes)
• Nucleotides have a three-part structure:
1. A five-carbon sugar (ribose or deoxyribose)
2. A phosphate group
3. A nitrogen-containing base

There are two types of nucleotides
•Ribose nucleotides (contain the sugar, ribose)
 bond to four types of nitrogen bases: adenine, guanine, cytosine, and uracil
•Deoxyribose nucleotides (contain the sugar, deoxyribose)
 bond to adenine, guanine, cytosine, and thymine

Nitrogen bases are divided into two groups
1. Purines – double ring structure (adenine and guanine)
2. Pyrimidines – single ring structure (thymine, cytosine, and uracil)

•Nucleotides are strung together in long chains to form nucleic acids
•Phosphate group of one nucleotide covalently bonds to the sugar of the next

• Deoxyribonucleic Acid (DNA)
1. Double helix
2. Deoxyribose sugar
3. Contains A, C, T, and G (A-T, C-G)
4. Makes up chromosomes of all living things
5. Sequence of nucleotides spells out information to construct proteins
• Ribonucleic Acid (RNA)
1. Single helix
2. Ribose sugar
3. Contains A, C, U, and G (A-U, C-G)
4. RNAs are copies of DNA – carries message to cell to direct synthesis of proteins

Nucleotides have many functions – not all are part of nucleic acids
• May exist singly or occur as parts of other molecules
• Some act as intracellular messengers to carry information from cell membrane to other molecules in cell – ex. cyclic AMP
• Some nucleotides have extra phosphates groups – ex. Adenosine triphosphate (ATP), Adenosine diphosphate (ADP)
1. Unstable molecules that carry energy from place to place – pick up energy where it is produced
(cellular respiration) and give up energy to drive energy demanding reactions elsewhere
•Certain nucleotides assist enzyme in their role of promoting chemical rxns – coenzymes – usually consist of a nucleotide combined with a vitamin