Wed 3.6.2013 • Today’s Objectives(Write on today’s NOTES!) • Review the structure & function of DNA • Prepare for the DNA extraction lab
TAKE NOTES! Nucleus; in eukaryotes Double Helix 4 base pairs (A,C,G,T) Chromatin which condenses into chromosomes
Cell wall (only in plants) 2. Nuclear Membrane 3. Cell Membrane
To extract the DNA ….. Which parts of the cell do you have to go through to remove the DNA? BARRIERS TO OVERCOME BARRIER 1: Cell Wall (only in plant) BARRIER 2: Cell membrane BARRIER 3: Nuclear membrane
BARRIER 1 - Cell Wall EXTRACTION PROCEDURE ACTIVITY FUNCTION Mashing/Crushing This breaks open the cell (LYSE) wall, cell membrane, and the nuclear envelope to allow the DNA to be released.
BARRIER 2 – Cell Membrane&BARRIER 3- Nuclear Membrane EXTRACTION PROCEDURE ACTIVITY FUNCTION Detergent (buffer) Breakdownthe fat and proteins that make up the cell and nuclear membrane. (Just like the detergent dissolves grease on your dishes).
Cell Membrane What components make up the membrane that surrounds the cell? REMEMBER Cell membranes are made ofphospholipids
Cell Membrane Phospholipids are bi-layer, with a head and a tail. the head –LOVES WATER the tail – HATES WATER Phospholipids won’t dissolve in water HATES Water: HYDROPHOBIC LOVES Water: HYDROPHILIC
Breaks open the cell Breaks open the cell membrane and nuclear membrane
Protein wrapped around DNA EXTRACTION PROCEDURE ACTIVITY FUNCTION Meat tenderizer (Enzyme) Adding an enzyme, such as meat tenderizer will break down proteins such as nucleases and histones that are wound around the DNA.
Breaks open the cell Breaks open the cell membrane and nuclear membrane To cut proteins away from the DNA
Filter EXTRACTION PROCEDURE ACTIVITY FUNCTION Filter Separate the components of the cell
Breaks open the cell Breaks open the cell membrane and nuclear membrane To cut proteins away from the DNA Organelles, broken cell wall, membranes from proteins, carbohydrates
Last Step! EXTRACTION PROCEDURE ACTIVITY FUNCTION • Alcohol DNA does not dissolve in alcohol. (It is soluble in water). The addition of alcohol causes the DNA to precipitate.
Cold slows down molecules helping them clump together Alcohol is a weak polar solvent—causing insoluble DNA to separate out
DNA Extraction Protocol DNA eNzymes (meat tenderizer) Alcohol Detergent Dissolve cell membranes Break down proteins Precipitate DNA Just follow these 3 easy steps: