Lecture Notes Chp 3

LECTURE NOTES CHP. 3

BIOMOLECULES/BIOCHEMISTRY

CARBOHYDRATES: General formula– (CH2O)N Example: Glucose - C6H12O6 Functions in cells include – intermediate source of energy, short/long term storage and structural compounds, organic compounds with a hydroxyl group (OH) on each carbon. okay MONOSACCHARIDES: Simple/single sugars Roll in cells: immediate energy source, (Ex: Glucose) and as building blocks of other compounds. (Ex: Ribose) Examples: Glucose Fructose Ribose (RNA and DNA) Many isomers exist in these monosaccharides Example: Structural isomers alpha and beta glucose Also stereo isomers = D and L forms (mirror images) In living cells, the D form predominates. DISACCHARIDES: Literally means 2 sugars 2 simple sugars linked by a glycosidic bond (c1 = linkage of the 1 place, c2 = linkage of the 4 place: c1-o-c2) Used primarily as transport molecules in plants. Example: We harvest sucrose (table sugar) from sugar cane. 3 Examples: Glucose + Glucose = Maltose Glucose + Fructose = Sucrose Glucose + Galactose = Lactose POLYSACCHARIDES: Literally means many sugars Long chain molecules of Glucose linked by Glycosidic bonds Storage

Structural

Animals and Fungi Glycogen- Branched chain stored in liver and muscles. Chitin- Found in arthropod exoskeletons and fungal cell walls.

Plants Starch (Amylose) Straight chain stored in underground parts (roots, tubers, etc.). Cellulose- Plant cell walls.

LIPIDS: Organic molecules which are not soluble in water. Non polar, neutral compounds with NO separation of charge nor unequal sharing of electrons. FUNCTIONS: STRUCTURAL – Phospholipids are the basic building blocks of cell membranes.

Energy storage – Long term energy storage (Animals = fats, Plants = oils) Signal molecules – Hormones- sex hormones (testosterone and estrogen) A signal molecule produced at a signal site and typically having it’s targeted effect far from sight of its production. (Example: Testosterone is made in your pituitary gland and is used in the testes.) PROTEINS: Organic molecules formed by a linear polymer of amino acids linked by peptide bonds. The synthesis of polypeptides is by condensation reactions. Only when a polypeptide takes on its final shape, does it become a functional protein. PRIMARY STRUCTURE: The genetically determined sequence of amino acids. (Ex: ALA-LYS-PRO- HIS) SECONDARY STRUCTURE: Two recurring shapes that form as a result of the primary sequence: Alpha helix + beta pleated sheet. TERTIARY STRUCTURE: Protein folding due to interactions of R groups with their environment.