DNA Day
Wednesday, March 23, 2011
Oswald Theodore Avery (1877-1955)
Tuesday, March 22, 2011
Forensics
Some examples of Forensic DNA:
- help identify a suspect using evidence from a crime scene
- fraternity and finding family relationships
- to match organ donors with the receiver
- identify victims where there physical appearance is severally change in an indecent
Monday, March 21, 2011
Central Dogma
DNA synthesis bind to specific regions of the chromosomes which is the replication origin.In prokaryotes there is only one origin for replication. The small chromosomes can replicate rapidly. Eukaryote although contain several chromosomes. Once the DNA double helix is at the origin and separates, an enzyme starts for preparation of each of the individual strands of DNA for synthesis. When the replisome moves away from the replication origin it starts to unwind the double helix. The replisomes move away from the replication origin along the DNA in both directions. The results of the process replaces the old DNA double helix with 2 identical ones. After adding a new nucleotide to the chain it goes through a check point to see if everything is correct. And if there is an error in the enzyme, the enzyme will put everything in a stand still and it'll remove the nucleotide and replace it with a correct one. If there is a mutation the enzyme would bind it to DNA and it'll break the sugar phosphates bonds of the mutation and fix it correctly.
Transcription:
(is the process of the making of a mRNA molecule) Happens in three stages the Initiation is the 1st stage. Its occurs when the enzyme RNA polymerse attaches to a specific region of the DNA. This are is known as the promteter region. But in the eukaryote cells the proteins need to present for the RNA polymerse to join itself with the prometer region. The 2nd stage is known as the Elongation. The Elongation is when the RNA polymerse begins to break the DNA. The enzyme travels with the DNA away from the prometer. A strand of RNA is created known as the primary transcript. The 3rd stage is known as Termination. Its when the RNA polymerse reaches at the end of the DNA to be transcribed. The primary transcript and the enzyme id then released.
Translation: When the protein synthesis moves the codon sequence of the mRNA to the amino acid sequence of a protein. One end of the RNA molecule carries a specific amino acid and the other side is the anti codon. The anti codon pairs with the mRNA . When the correct amino acid conbines with tRNA is called tRNA charging. Each enzyme bonds a different amino acid to its match tRNA by the energy from ATP. The tRNA and mRNA and the polypeptide chain come together at a specific region on the ribosomes. The tRNA leaves the E site after its amino acid is added to the polypeptide chain. The ribosomes move along the mRNA strand at a time.
Structures of DNA, tRNA and mRNA
DNA's backbone is based on a repeated pattern of a sugar and phosphate group. The Genetic parts of the DNA are found in the "Steps" of the structure. (nitrogen bases) The Bases are on the inside and the backbone is on the outside.(1)
It also has two strands of nucleotides that form a spiral stair case looking figure. Each nucleotide contains three parts; Phosphate group, sugar molecule and one of four bases. Those four bases are admine, guanine, cytosine and thymine. The bases link up using hydrogen bonds; Admine to Thymine and Cytosine to Guanine. The pairs never change but the pattern can very depending on the species.(2)
Structure of tRNA
Transfer RNA brings out the amino acids to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. All tRNA's have a similiar sequences of 73-93 nucleotides. The image of tRNA is in a compact "L" shape. (4) Transfer RNA has three structures; A primary, secondary and a tertiary. Each one contains a specific anticodon triplet sequence that can be a base pair to one or more codons for an amino acid. (3)
Structure of mRNA
Tuesday, March 15, 2011
J.Craig Veneter and Francis Collins
The human genome project is an international reserch project with the goal of finding out the sequence of chemical base pairs of DNA. THe project began in the early 1990's. The project mostly focused on the genetic make up of human beings. The project also researched/ studied on E Coli, fruit flies, and lab mice. For the human side of the research , there were willing blood donors of male and females. The project was very expensive so they decided to use the ''shotgun theory'' which was to breakup the genome into smaller pieces into ''Vectors''. These vectors can be inserted into bacteria so that they could be copied using DNA replication. The genome that were broken apart are mapped out to chromosomes.
The contributions of Veneter and Collins to the Human Genome project toward DNA are still increasing now. A better understanding of DNA for new advancements in medicine and biotechnology, Genetic tests to find diseased genes such as breast cancer and liver disease.
Watson & Crick 1953 - Double Helix Structure of DNA
Friday, March 11, 2011
Martha Chase and Alfred Hershey
Biologists thought that proteins are carried there information through inheritance since 1869. Chase and Hershey created there experiments on a virus known as "T2 phage". This virus infects baceterium by connecting its outer membrane and injecting its genetic material and leaving the empty shell on the bacterium. First they allowed the virous to infect E.Coli (in this experiment they observed that there was a transfer of P32 labeled virous its DNA was in the cytoplasm of the bacterium. in there second experiment they conducted they labeled the virous with radioactive Sulfur-35. After the seperation the radioactive S35 tracer was in the protein shells, but not in the infected bacteria. This in conclusion they found that the genetic material that infected the bacteria was DNA not protein. Chase and Hershey recieved the Nobel peace prize for their ''discovers concerning the genetic structure of virouses.''
Martha Chase and Alfred Hershey's findings that DNA is genetic material contributes to the better understand of virouses. With having a better understanding of virouses helped other scientests to develop vaccines against diseases such as polio.With there new information about DNA; Chase and Hershey creates ther blender experiment. A year after there blender experiment James Dewey Watson and Francis Harry Compton Crik deterimined that DNa is in a double helix type structure.