Do you look like your parents Where did

Do you look like your parents? ? • Where did you get the color of your hair from? • Are you going to be bald like your dad? • Do you have the same body shape as your mom?

• Our traits come from genes • Genes are found on chromosomes • Chromosomes are made of coiled up DNA

• DNA is located in the nucleus of a cell • DNA stands for deoxyribonucleic acid

DNA is the genetic code or program of the cell, passed from generation to generation - Different body cells of same organism contain same amount of DNA (46) except sex cells, sperm and egg, which contain 23 each.

Structure of DNA, polymer made of units called nucleotides. -Composed of: 1. sugar 2. phosphate 3. base.

Bases • • Adenine (A) Thymine (T) Guanine (G) Cytosine (C) * There is also a U (Uracil) that is in RNA

Rosalind Franklin purified and stretched DNA molecule shot X - rays through strand recorded pattern on film Clues to structure of DNA * twisted like rope (a double helix) * Large molecules spaced at regular intervals.

Watson and Crick attempted to make a three dimensional model of DNA molecule With Franklin's X - ray pattern Watson and Crick within weeks figured out the structure of DNA Their model was almost immediately accepted. Won 1962 Nobel prize (Watson, Crick, Wilkins, Franklin if alive).

Base Pairing

Base Pairing • A bonds to T • G bonds to C A-T G-C * A way to remember this is the saying: “At Grand Central” Question: What would the complementary strand be for the following sequence? TCAGCCACCTATGGA AGTCGGTGGATACCT

The Cell Cycle Review: • What is the cell cycle? • What must happened to a cell’s DNA in order for it to divide properly?

Mitosis and DNA Replication • Before a cell divides, its DNA must be duplicated, so that each cell has an exact copy of the original DNA. This is called replication. http: //web. mit. edu/esgbio/www/cb/mitosis. gif – This process takes place during the interphase step of mitosis.

DNA Replication Watson and Crick’s model provided a quick and easy way to see how DNA copies itself. The other half of a DNA strand is built through base pairing. Each half of the DNA strand is said to be “complementary” or matching to the other. Ex. A T C C G T A A C T T G T A G G C A T T G A A C

Enzymes are involved in DNA replication. One enzyme "unzips" the two strands, like a pair of scissors. Another attaches the appropriate bases, like glue. • Other enzymes are involved in this process.

Sources • • • www. accessexcellence. org/AB/GG/genes. html http: //biology. clc. uc. edu/graphics/bio 104/cell. jpg http: //fig. cox. miami. edu/~cmallery/150/gene/16 x 5 bc. jpg http: //library. thinkquest. org/20830/Textbook/DNAStructureandfunction/Nucle otide. htm http: //www. daviddarling. info/images/cell_cycle. jpg http: //www. ba-education. demon. co. uk/gifs/mitosis. jpg • Gerard J. Tortora Sandra Reynolds Grabowski Principles of Anatomy and Physiology Tenth Edition 2003 published by John Wiley& Sons, Inc. • Marcia Bhide http: //www. edugraphics. com/marcia/images/Albums/Anatomy/Epithelium/slides/Epi thelium%20006. jpg • http: //www. defiers. com/sc. jpg • Biology Prentice Hall, Miller and Levine 2002