Bellringer Wed, 01/07 Replicate the following DNA strand (hint: find the complementary nucleotides and remember your base pairings) ATGGCTAGCCTTTTAACGC What is RNA? Look it up! Reminders: HW #17 due Fri, LAB FEE anytime, 5 days to FINAL EXAMS!

DNA Which objects contain DNA?

Prior Knowledge DNA is found in the cell of every living thing. Proteins that help DNA maintain its form may obscure our ability to see the DNA so they must be removed. Among eukaryotes, DNA is contained in the membrane wrapped nucleus. The cell membrane is made of lipids with embedded proteins.

DNA Facts Each cell contains 9 feet of DNA In an average meal, you EAT approximately 55,000,000 cells This is equal to approximately 93,205 miles of DNA If the total DNA in one person were laid in a straight line, it would stretch to the sun and back over 30 times (it’s 93 million miles from here to the sun)

Problem The Biotech Foods Company is developing an improved strain of bananas through genetic engineering. In order to obtain DNA that they can examine and use, scientists working for the company must extract the DNA from banana cells in a way that does not destroy the DNA molecules. Conditions that can damage or destroy DNA molecules include exposure to heat, acids, and ultraviolet radiation. In this lab you will follow a simple procedure for extracting DNA.

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) Breakdown the 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 of phospholipids

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 LOVES Water

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.

Filter EXTRACTION PROCEDURE ACTIVITY FUNCTION Filter Separate the components of the cell

Last Step! EXTRACTION PROCEDURE ACTIVITY FUNCTION Alcohol DNA does not dissolve in alcohol. (It is soluable in water). The addition of alcohol causes the DNA to precipitate.

DNA Extraction Protocol Just follow these 3 easy steps: Dissolve cell membranes Break down proteins Precipitate DNA DNA Detergent eNzymes (meat tenderizer or salt) Alcohol