DNA and Protein Synthesis

A. Nucleic Acids and Protein Synthesis

• All functions of a cell are directed from some central form of information.
• This "biological program" is called the Genetic Code. It is where as the way cell store information regarding its structure and function.

B. History

• For years the source of heredity was unknown. this was resoled after numerous studies and experimental research by the following researchers: 

1. Fredrick Griffith
               He was studying effects of 2 strains of an infectious bacteria, the "smooth" strain was found   to cause pneumonia and death in mice. the rough strain did not. He conducted the following experiment:

Source: http://www.ibri.org/Books/Pun_Evolution/Chapter2/fig2-41.jpg

• The last condition was unusual, as he predicted that the mouse should live.
• Concluded that some unknown substance was transforming the rough strain into the smooth one.

2. Avery, McCarty and MacLeod

•  Tried to determine the nature of this transforming agent. E.g. was it protein or DNA?
• Degraded chromosomes with enzymes which destroyed proteins or DNA.

Source: http://chsweb.lr.k12.nj.us/mstanley/outlines/dna/image8.gif

• Samples with proteins destroyed would still cause transformation in bacteria indicating genetic material was DNA. 

3. Hershey-Chase

• One virus was tagged with 32P on its DNA.
• The other was tagged 35S on its protein coat.
•  Researchers found the radioactive P in the bacteria, indicating it is DNA, not protein being injected into bacteria.

Source: http://www.accessexcellence.org/RC/VL/GG/images/HERSHEY.gif

4. Watson and Crick

• The constituents of DNA had long been known. Structure of DNA, however was not.
•  In 1953, Watson and Crick published findings based on X-ray analysis and other data that DNA was in the form of a "Double-Helix".
• Their findings show us the basic structure of DNA which is as well as we know now.

Source: http://www.g2conline.info/content/c16/16427/16427_watsoncrickatcambridge.jpg

C. In this blog we will talk about DNA and Protein Synthesis with detail as follows: 

1. DNA Structure and Function

• DNA Structure and Function
• DNA Replication

2. Protein Synthesis

• Genetic Code
• Transcription
• Translation