Central Dogma - msgoodwin.com · Central Dogma The classic view of the central dogma of biology states that "the coded genetic information hard-wired into DNA is transcribed into

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Central DogmaThe classic view of the central dogma of biology states that

"the coded genetic information hard-wired into DNA is transcribed into individual transportable cassettes, composed of

messenger RNA (mRNA); each mRNA cassette contains the program for synthesis of a particular protein (or small number of

proteins)."

Sources: Definition from Chapter 1: The Dynamic Cell, of Molecular Cell Biology.Sources: Definition from Chapter 1: The

Dynamic Cell, of Molecular Cell Biology.

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What genetic material needed to be able to do:

1. Store information to control activities of the cell2. Be copied for cell division3. Be able to undergo mutations to provide genetic variability

But how & what molecule was responsible for this?

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16. 1 Timeline of the road to the discovery of the structure of DNA, on the pathway to the Central Dogma discovery

1869: Miescher removed nuclei from cells & discovered a material called nuclein, became nucleic acid

Later: became nucleic acids. 2 types: RNA & DNA

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16.1 DNA is the Genetic Material: Timeline of the road to the discovery of the structure of DNAA. 1928: Griffith‛s Transformation Experiment

1. Investigated virulence of pneumonia bacteria2. Concluded that DNA(something) was passed from the dead S (shiny smooth

colonies) strain to the living R (rough colonies) strain - changed the genotype and the phenotype

3. Discovered transformation/transforming factor (DNA/gene)

Griffith & Avery mice animationhttp://dnalc.org/view/15012-Oswald-Avery-.html

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B. 1944: Avery & McCarthy & MacLeod published a paper explaining that DNA was the transforming material1. Only Dnases (enzymes that destroy DNA), not Rnases or proteases stopped transformation. DNA is the transforming substance2. DNA from dead cells was being incorporated into genome of living

cells• Avery video clips: http://www.dnaftb.org/17/av.html

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C. 1952: Hershey & Chase1. Determining which from a virus(bacteriophage), DNA or protein, enters

a bacterium.2. Whichever does, must be the genetic material.

- Viruses are not capable of reproducing on their own -Viruses must enter a cell and then use the cell‛s enzymes and ribosomes to create new viruses- Viruses are not composed of cells so are considered

nonliving.

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• 1. Results indicated that DNA, not the protein capsid, enters the host, therefore DNA is the genetic material of viruses

• http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120076/bio21.swf::Hershey%20and%20Chase%20Experiment

C. 1952: Hershey & Chase

(C,H,O,N,S)

(C,H,O,N,P)

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D. Chargaff's Rule or the Rule of Base Pairing

1. The amount of adenine is = to thymine

2. The amount of guanine = cytosone

E. 1951 & 1952: Rosalind Franklin

1. X-ray diffraction

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F. 1953: Watson and Crick

1. the 2 strands are antiparallel a. the sugar phosphate groups are oriented in different directions. b. the 5' end is opposite the 3'end

Nucleotide

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