Transcription vs. translation vs. replicaiton

Initiation: 

Transcription	Translation	Replication
-          TATA box (DNA), signals Transcription Factors (proteins), which then signals the Polymerase II -          Polymerase II recognizes a base sequence in the DNA specifically called a promoter and binds to it, the Polymerase II then starts unwinding the double helix structure and starts reading the DNA sequences	-          small subunit (ribosome) binds to 5’ cap of mRNA -    tRNA (has methionine attached to it already)  attaches itself to the small subunit  -          big subunit (ribosome), containing 3 sites, the A (acceptor) site, P (peptide) site, and  E (exit) site binds to the small subunit	- Helicase untwist  the double helical structure and breaks hydrogen bonds and opens up the  DNA strand - Gyrase relieves tension from unwinding - Single-Strand Binding Protein protects the single stranded DNA from water - Primase: makes RNA primer that is used to signal the Polymerase III -

Elongation 

Transcription	Translation	Replication
-          Polymerase II reads DNA template strand (also named antisense strand) from 3’ to 5’, which is similar to the Coding strand (also named sense strand) -     Polymerase II matches the corresponding nucleotides to the unzipped nitrogen bases of the gene, which would form a single strand of pre-mRNA, the pre-mRNA is formed from 5' to 3' -          The Polymerase II replaces thymine with uracil in the pre-mRNA	-          The ribosome reads the codes in triples (codons), translation only occurs when the ribosome reads the start codon which is AUG and corresponds to the amino acid methionine -          tRNA’s anticodon recognizes the complementary base sequence on the mRNA -          aminoacyl-tRNA synthetase (enzyme) brings in the correct amino acid, then attaches it the 3’end of tRNA  -     the tRNA then brings the correct amino acid to the A site, when a second amino acid comes, the first amino acid translocate into the P site. -          The peptide bond is formed between the first the second amino acid , then the first tRNA enters the E site, when a third tRNA with the correct amino acid comes, and then leaves  -           this cycle continues with a fifth amino acid entering the A site then moves to the P site when a sixth amino acid comes in	- Polymerase III  reads strand from 3’ to 5’ and makes the DNA from 5’ to 3’ - one of the strand will be the leading strand, this strand will be elongated continuous, while the other strand, the lagging strand, will be made discontinuously. The lagging fragments are called Okazaki fragments

Termination 

Transcription	Translation	Replication
- AAUAA sequence (RNA) stops the production of RNA - then pre-mRNA is released for further modification  -  the DNA structure reforms its double helical shape	-          elongation stops when a stop codon (UAG, UGA and UAA) is read in A site, then ribosome stalls -          Release Factor recognizes the stall of the ribosome and causes the ribosome subunits to leave and to release the polypeptide chain	G – after all the nucleotide are replicated, Polymerase I double checks and fix any mistakes made and also remove the primers - k – Ligase then glue all the DNA back together and glue the gaps - -

Watson and Crick 

Francis Crick and James Watson was a pair of scientist who discovered the structure of DNA, they uncover the double helix nature. Francis Crick studied physics and received a BS degree in that branch of science. However Crick was interested in biology and decided to focus on the effects of x-ray on proteins. James Watson studied the effect of x-ray on bacteria in the Indiana University and received a degree in zoology. When the two met, which was by chance, they discovered that they both wanted to uncover a gene’s true structure. In 1953, after many experiments with paste and cardboard, they finally figured out that DNA was composed of two double-helical configurations, however no matter what they did; it always ended up as a ladder shape. They couldn’t figure what shape was the perfect figure that allowed genetic information to be protected. They found their missing puzzle when they saw Franklin’s work and knew that the secret was that the double helical configuration had to be twisted. Their founding explained how DNA replicates and how hereditary and genetic information are coded on the DNA.  In 1962, Crick and Watson won the Nobel Prize in Medicine for discovering the structure of DNA, which became one of the most important discoveries of the 20^th century. Crick then continued to work in genetic field and later moved into brain research. On the other hand, Watson, at the American National Institutes of Health, became the director of the Human Genome Project there.

     "BBC - History - Historic Figures: Watson and Crick (1928- )." BBC - Homepage. Web. 08 Feb. 2012. <http://www.bbc.co.uk/history/historic_figures/watson_and_crick.shtml>. 

Maurice Wilkins (Maurice Hugh Frederick Wilkins, 1916-2004) 

Maurice Wilkins was born on December 15, 1916. His father was a doctor and was very interested in research but didn’t have the opportunity to. Wilkins had a degree in physics in 1938 and retained his Ph.D in 1940. He applied his studies and ideas to various war-time problems, but when the war was over he began his research in biophysics. In 1946, his biophysics project moved to king’s College where he became a member of the newly formed Medical Research Council Biophysics Research Unit. He then formed a partnership with Rosalind Franklin. In 1953, together with Franklin, they published their first x-ray diffraction pictures of DNA in Nature, but Wilkins was second author while Franklin became the first author. Further studies established and helped the Watson-Crick proposal for DNA structure. In 1959, Wilkins married and as a result of their marriage one girl and one boy was born later. In 1962, due to Franklin’s death, Wilkins was rewarded the Nobel Prize. 

     "Maurice Wilkins - Biography." Nobelprize.org. Web. 08 Feb. 2012. <http://www.nobelprize.org/nobel_prizes/medicine/laureates/1962/wilkins-bio.html>.

Gregor Mendel (July 1822 – January, 1884): 

Gregor Mendel was an Austrian monk, botanist and plan experimenter, whom already had a strong foundation for mathematics and science. He began as a high school teacher who taught nature science, his love for nature was what drove he to find his discovery. He is often referred to as the father of genetics and the first person to discover the basic laws of heredity and came up with the idea that genes existed. In his gigantic pea plant he found the secret to genetic, and also developed two laws; the law of segregation and law of independent assortment. Law of segregation stated that alternative versions of gene are responsible for variations in inherited characters. Law of independent assortment stated that each pair of alleles will segregate independently of the other pairs of alleles during the formation of gametes. He also held the important link to Darwin’s theory of natural selection. His founding was rediscovered in modern times and became the foundation of modern genetics and heredity. He chose peas as his test subjects, because of the distinct features of peas. Like other scientist, Mendel did publish, but his work was not taken seriously and he did not become famous or rich during his life time. 

     "Gregor Mendel - Biography." Angelfire: Welcome to Angelfire. Web. 08 Feb. 2012. <http://www.angelfire.com/zine/baptistsurfer/BioMendel.html>.