4/20/12Bell Ringer

I'm called by three lettersThough I have a long name.

I'm in all of you,But I'm never the same.

I'm all coiled upSo that I am quite small,But if you stretch me out

I'll be really tall.

I could be the root Of certain disease;

If man can unlock meHe'll solve many mysteries.

WHAT AM I?!?!

DNA Pg. 281-284

What Is DNA?DeoxyriboNucleic Acid (DNA)

oDiscovered in 1953

o James Watson and Francis Crick with the help of Rosalind Franklin

Located in the nucleus of cells

Coiled as chromosomes

Your DNA contains sections of heredity traits (genes)

DNA Codes For Proteins (enzymes)

o Large complex molecules that do most of the work in cells.

oRequired for the structure, function, and regulation of the body’s tissues and organs.

o Enzymes control the chemical reactions needed for life.

DNA Structure/ ShapeDouble HelixLike a twisted zipper

Structure on the outside:

- Phosphate + sugar (deoxyribose) on the inside - Nitrogenous bases (A, T, G, C)Phosphate + Sugar + Nitrogenous Base= Nucleotide

Nitrogen BasesBase Pairs:Adenine (A) ------ Thymine (T) Cytosine (C ) ------ Guanine (G)• Attached by weak Hydrogen Bonds

The sequence of nucleotides form the unique genetic information of an

organism

What Does DNA Do

Codes for proteins and traits like arecipe for that organism!!

HOW?1. Replication2. Transcription3. Translation

What is DNA Replication?

Replication= Copying

- Before Mitosis and Meiosis during Interphase

3 Step Process of Replication

1. DNA strand “Unzips”

3 Step Process of Replication

2. Base pairing of new nucleotides to original strand

3 Step Process of Replication

3. Matching of base pairs until two DNA molecules are formed

Each one identical to the original.

Let’s Predict the complementary strand of DNA

A C G T A A C T G G

A C G T A A C T G GT G C A T T G A C C

Let’s Try One More

T G A C A C T A G A T A C C C G T A T C

T G A C A C T A G A T A C C C G T A T CA C T G T G A T C T A T G G G C A T A G