Synthesis Of Dna Research Paper

Transcription is the formation of an RNA strand from a DNA template within the nucleus of a cell. There are four nucleotides of DNA. These are adenine, cytosine, guanine and thymine. These nucleotides are transcribed to form messenger ribonucleic acid (mRNA) consisting of nucleotides made of adenine, cytosine, guanine and uracil. This transcription from DNA to mRNA happens by an RNA polymerase II. This newly created mRNA is read in the 5' to 3' direction in sets of 3. These sets are called codons. Each mRNA also has a cap and end. On the 5 prime side is a methylated guanine triphosphate and on the 3 prime is a poly A tail. Messenger RNA then moves to the cells cytoplasm and through the cells ribosomes for translation. Messenger RNA is matched to molecules of transfer RNA (tRNA) in the ribosomes to create amino acids. These amino acids subsequently form an amino acid chain. (Osuri, 2003) A visual representation of this can been viewed in figure 3.

In eukaryotes, stored primarily in the cell nucleus. A nucleic acid using deoxyribose rather than ribose.

The minimum number of nucleotides needed to code for the the protein is 777(258x3 + the stop codon). There are many codons before the start codon and after the stop codon, only the 751 between the two actually come for a

There are three types of RNA: mRNA, tRNA, and rRNA. Messenger RNA (mRNA) is synthesized from a gene segment of DNA which ultimately contains the information on the primary sequence of amino acids in a protein to be synthesized. The genetic codes is translated is for mRNA, not DNA. The messenger RNA carries the code from the nucleus to the ribosome in the cytoplasm where protein synthesis occurs. It also carries the genetic information copied from the DNA in the form of a series of three-base code “words”, also known as triplets, each of which specifies a particular amino acid. Each nucleotide triplet, called a codon, can be “read” from the mRNA and translated into an amino acid to be incorporated into a protein being synthesized. Messenger RNA is a

Before leaving the nucleus the pre-mRNA may go through a process called RNA splicing (Brooker). During this process the undesirable introns are disposed of while the coding sequences, exons, are spliced together to form messenger RNA (Brooker). Understanding RNA splicing, the most important process that may alter a protein’s shape is alternative splicing (Brooker). This process allows one strand of pre-messenger RNA to produce several different polypeptide sequences (Brooker). One pre-mRNA can create multiple polypeptide sequences which in turn creates proteins that are distinctive from each other. Alternative splicing is seen in the LMNA gene, it produces Lamins A and C (Swahari). Although they are different proteins, they are believed to be functionally redundant (Swahari). During the formation of these proteins a farnesyl group, which embeds into the cell membrane, is added to one end and later the protein is cleaved at a recognition site in exon 11 removing the tip and the farnesyl group (Swahari). Due to the point mutation linked to HGPS 50 amino acids are removed, within these is the recognition site (Swahari). As a result the protein is permanently farnesylated and known as progerin (Swahari). This protein imbeds and accumulates in the cell membrane creating the symptoms of HGPS (Swahari).

Once the initial proteins are made, then eight complementary positive sense RNA strands are made from the eight negative sense RNA segments (at least in influenza A and B. . . influenza C has seven segments). These lack the 5' capped primer, as well as the 3' poly (A) tail found in the mRNA. From this cRNA, a negative sense RNA is produced. Various proteins then help this negative sense RNA exit the nucleus and into the cytoplasm of the host.

the DNA. Binding of the regulatory protein activates transcription which results in the production of mRNA product which is then translated to protein product.

Ribonucleic acid (RNA): It is a single nucleic acid supported by adenine, guanine, cytosine and uracil supported by ribose sugars. mRNA, rRNA and tRNA.

The substrate binding domain has a specific sequence antisense to the target mRNA. This sequence recognizes and hybridizes specifically to its substrate. (Missailidis, 2008). Alteration of the substrate binding domain can be done so that the substrate specifically cleaves any mRNA sequence. The RNA catalytic domain cleaves the substrate at a target site recognized by the ribozyme (Glick &Pasternak, 2003).

In the early 70s it was observed that the ribonu-cleoprotein precursors to ribosomes contain two classes of protein. The difference between these proteins was thought to be that one class could be recognized as ribosomal proteins,

It is lighter to carry around. Since mRNA has to move from inside the nucleus to the cytoplasm.

(Except that uracil replaces thymine). The nucleotides form sugar-phosphate bonds with each other and become an mRNA strand but they do not form bonds with the DNA strand. The sequence of three exposed bases on mRNA, that are complimentary to the base triplet on the DNA, are known as codons. Once the mRNA strand is complete it moves from the DNA in the nucleus, through the nuclearpore into the cytoplasm where it drapes itself over the ribosomes with their codons exposed. Floating in the cytoplasm are tRNA molecules which job is to pick up specific amino acids and transport them to where the mRNA is draped.

When each sub-genomic mRNA is translated into a single polypeptide, they will assemble with a nucleocapsid protein in the cytoplasm to form helical nucleocapsids which are to be released from the host cell to infect other cells (Brooks et al., 2007).

The first step is the binding of the next tRNA to an anticodon complementary to the next mRNA codon. The amino Acid carried by this trNA will be the next amino acid in the polypeptide chain.

c. Messenger RNA is a single-stranded RNA molecule that carries the instructions from a gene inside of the nucleus that is always strand number 1 to make a protein. The transfer RNA transfers amino acids to the ribosome to make the protein.