Structure and Function 1) Choose an item. Explain - How does the structure of this item support its function? 2) What should be the functions of DNA? What would you expect this molecule to do?

Journal: Anticipation Guide handout. -Answer on your own. -Share afterwards with your neighbor -Turn it in. -Will be answered again, later in the unit.

James Watson and Francis Crick 1953.

1940’s: DNA is the genetic material * A chemical from dead harmful bacteria can transform nearby ‘naive’ cells to become harmful. * Not a protein: No Sulfur, lots of phosphate, breaking down proteins does not prevent it action.

The Structure of DNA was discovered based on it’s predicted functions as the genetic material: 1. DNA contains specific genetic information. 2. DNA carries information to the next generation: by accurate replicating.

Early information about DNA structure: 1) Monomers: Nucleotides A, C, G, T 2) Chargaff’s Rules: The amount of each nucleotide show a universal behavior: A=T, C=G. 3) Three dimensional data: Twisted Ladder

Purines Pyrimidines Adenine Guanine Cytosine Thymine DNA is a chain of nucleotides:

James Watson and Francis Crick 1953.

Try and Figure it out! Use the materials you have in hand and the clues from ‘previous knowledge’ to build a DNA model.

Powernotes: DNA Fill in the handouts, then color the back side, according to directions.

Considering the two models of DNA. A. Compare: Which parts are similar? Which parts are different? (ignore ribbon color) B. Where in the molecule might the specific information be? C. How might DNA replicate? Journal 2

View the animation of replication. Describe what you see in at least three bullets – You can add a drawing for support, but this is not mandatory J3

Replication – AnimationReplication – Animation: Fast Animation of Replication Lewport NOBEL PRIZE RePLICATION Detailed but clear! DNA Replication - Calsszone

Building DNA from models: Pipes: pick up -20 black parts,10 connectors -20 white pipes -8 blue, yellow -10 orange, green -Beads: - 20 red, 20 white - 10 orange, green, blue, yellow, -10 connectors

Copy the following DNA strand: A G G T C C T A T G A. What would be the order of nucleotides in the opposite strand (blanks)? B. How many nucleotides are in each strand? C. How many phosphates and sugars are on each side of this DNA? J4

Animation of Replication Lewport Movie of DNA Replication (DNAi) * Speed of replication: ~50 base-pairs / second. * Human DNA contains about 150x10 6 (150 million) base- pairs. How long would it take to replicate? * It actually takes about an hour. Why?

Animation

Purines Pyrimidines Adenine Guanine Cytosine Thymine Phosphate groupDeoxyribose DNA is a chain of nucleotides: nucleotide

Adenosine Tri Phosphate (ATP) A-Nucleotide! Adenine Ribose (sugar) Phosphates

Source of DNAATGC Streptococcus Yeast Herring Human Streptococcus Yeast Herring Human Chargaff rules: In all organisms, A=TC=G

3. Rosaline Franklin, X-Ray Crystallography: DNA is made like a double twisted ladder