Structure and Function

Structure and Function1) 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

PurinesPyrimidines

Adenine GuanineCytosine

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?

07.20.11 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.

07.21.11 J3

Replication – 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?

07.21.11 J4

Animation of Replication Lewport

Movie of DNA Replication (DNAi)

* Speed of replication: ~50 base-pairs / second.* Human DNA contains about 150x106 (150 million) base-pairs. How long would it take to replicate? * It actually takes about an hour. Why?

Animation

PurinesPyrimidines

Adenine GuanineCytosine

Thymine

Phosphate group Deoxyribose

DNA is a chain of nucleotides:

nucleotide

Adenosine Tri Phosphate

(ATP)

A-Nucleotide!

Adenine

Ribose (sugar)

Phosphates

Source of DNA A T G CSource of DNA A T G C

Streptococcus 29.8 31.6 20.5 18.0

Yeast 31.3 32.9 18.7 17.1

Herring 27.8 27.5 22.2 22.6

Human 30.9 29.4 19.9 19.8

Streptococcus 29.8 31.6 20.5 18.0

Yeast 31.3 32.9 18.7 17.1

Herring 27.8 27.5 22.2 22.6

Human 30.9 29.4 19.9 19.8

2. Chargaff rules: In all organisms, A=T C=G

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