Molecular Biology of the Gene

What is Transcription?

The transfer of genetic information from DNA into an RNA molecule



What is Translation?


The transfer of the information in the RNA into a protein


What are the base nucleotides for DNA and RNA?

DNA: Adenine, Cytosine, Guanine and Thymine
RNA: Adenine, Cytosine, Guanine and Uracil


The Facts:
-DNA is arranged in a double helix shape (a sort-of molecular ladder), twisted.
-DNA nucleotides are only attached to the 3' end of a strand
-Daughter DNA can only grow in the 5' --> 3' direction
-The two main stages of RNA protein synthesis are Translation and Transcription
-In RNA protein synthesis, the only start codon is AUG
-The stop codons in RNA synthesis are: UAA, UAG, UGA
-tRNA matches amino acids to the correct codons to form new polypeptide chains
-The P Site on the ribosome is where the growing polypeptide is being held
-The A Site on the ribosome is vacant and ready for the next tRNA
-The most common method of mutagens come from radiation


Some Key Terms:
-Bacteriophages: Infects bacterial viruses
-Nucleotides: Chemical monomers
-Sugar-phosphate backbone: a repeating pattern of sugar-phosphate-sugar-phosphate
-Double Helix: Two strands of DNA
-Semiconservative model of DNA: Half of the parental molecule is maintained in each daughter molecule
-DNA Polymeras: Enzyme that links nucleotides to a growing daughter strand
-Triplet Code: The genetic information for an amino acid codes in chunks of three nucleotides
-Introns: Internal non-coding regions
-Exons: The parts of the genes that are expressed in the amino acids
-RNA Splicing: Introns are removed, exons are joined to form mRNA before leaving the nucleus


Diagram:

This is a diagram of DNA replication. As you can see on the side, the 4 monomers are labelled. You can also see the parent strands prior to splitting, in the process while the free monomers attach, and finally being coupled with a new complimentary strand.















Summary:


This chapter was about the molecular level of genetics, explaining replication of DNA as well as RNA replication and the production of amino acids.
Transcription occurs, translating a strand of DNA into RNA via free RNA monomers attaching. These are then Translated into amino acids through triplet codes, becoming a poly peptide chain of acids. But before leaving the nucleus, Eukaryotic RNA has its' introns removed and its' exons spliced as a coding sequence. The anticodon is the base triplet of a tRNA strand and couples the tRNA to the correct codon in the mRNA.
The chapter ends talking about viral DNA and how it integrates itself with the host chromosomes. It can either go through the lytic or lysogenic cycle. The lytic cycle destroys the cell shortly after infection, while the lysogenic cycle lets the cell divide a few times, letting the DNA copy itself before multiplying.

A Cool Video:


http://www.thedailyshow.com/watch/wed-july-10-2002/ted-williams--resurrection