Bellwork: Monday, Nov. 23, 2015 What are the two things genes do? Code for _____________________ And are __________________ from one _______________________________________

http://www. neok12. com/php/watch. php http://www.neok12.com/php/watch.php?v=zX1f096c43446b7c624d540a&t=Genetics Not this… but this…

Glitter pills Do not consume

Separating DNA from Buccal Cells

To investigate DNA, you must know the following: DNA Extraction in the lab • DNA is found in the cell of every living thing • Proteins and enzymes may obscure seeing the DNA, so it must be removed. • You must break thru a cell membrane to release your DNA. • Our DNA is contained in the membrane wrapped nucleus.

Collecting buccal (cheek) cells First make sure you have no residual food in your mouth from the last time you ate Swish 2 teaspoons (10 mL) of .9% salt water in your mouth, gently chew on the inside of your cheeks to scrape off as many cells as possible. Do this for about 30 seconds. Salty water helps the DNA precipitate (solidify and appear) when alcohol is added.

You are trying to loosen as many cheek cells as you can as you rinse

2. Spit the saltwater into a large test tube containing 1 teaspoon (5mL) 25 % liquid detergent.

3. Cap the test tube and gently rock it on its side for 2-3 minutes 3. Cap the test tube and gently rock it on its side for 2-3 minutes. The detergent will break open the cell membrane to release the DNA in to the soap solution. Caution: don’t be too vigorous while mixing! DNA is a very long molecule – mixing it too roughly will break it into smaller fragments known as shearing The gentle motion helps to break down the cell membrane

4. Open and slightly tilt the test tube and pour 1 teaspoon (5mL) fluid ounces of the chilled 95 % ethanol down the side of the tube so that it forms a layer on the top of your soapy solution Cold water helps keep the DNA intact during the extraction process. Cooling slows down enzymatic reactions. This protects DNA from enzymes that can destroy it.

5. Allow test tube to stand until the DNA rises to the top of the alcohol solution. You will see bubbles. These bubbles will pull the thin whitish DNA to the top.

Top of alcohol layer Bubble DNA

A large amount of DNA sometimes rises up

If desired place a glass or acrylic rod into the test tube and twirl to collect the DNA. Do not put the rod below the alcohol layer. Twirl or spool the DNA to place into a test tube with alcohol only.

Lab tech spooling DNA

DNA looks the same no matter what the souce becase the bases are always the same: A, T C and G http://topdocumentaryfilms.com/dna/

Bellwork: Wed. Nov. 28, 2012 1. Look at yesterday’s notes and label the replication fork 3’ 5’ Leading Strand Lagging Strand 3’ 5’