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BIOCHEMISTRY TASK 1

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THE ROLE OF DNA AND RNA IN REPLICATION
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Introduction
The standard view of molecular biology says that DNA keeps information about all our proteins and that they exist three types of RNA. Which, actively transform the codes to polypeptides. Of the three, the mRNA is responsible for transporting the information from the DNA to the ribosomes. The ribosome that converts the codes to amino acids.Deoxyribonucleic acid, or commonly referred to as DNA, is a molecule that is found inside every cell and which contains genetic information, (Hall 2011). The parent transmits the genetic information stored in the DNA to the offspring during reproduction. Two strands make up the DNA structure, which coil together to form a double helix. Each strand has four nucleotides within it. Which include cytosine; thymine, guanine and adenine, abbreviated as C, T, G and A respectively. Thymine and Cytosine are pyrimidines while guanine and adenine are purine bases.
This is what happens during DNA replication. An enzyme known as DNA gyrase initiates the splitting of the double helix, making them separate. Single strand binding proteins bind with each side for a while. After which the enzyme DNA polymerase passes through the strand creating or adding on new nucleotides. Then the nucleotides pair with other corresponding nucleotides. Finally, the enzyme DNA ligase joins the strand into one long strand.

(Source http://www.shmoop.com/dna/dna-replication.html)
Transmission of information within the cell involves two steps.

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Where in the first step the information in the DNA is transmitted to the M RNA through a process known as transcription. The second major step is known as translation, where mRNA is read, and the genetic code determined which is similar to the DNA sequence.
Three bases from the mRNA make up a codon. Each codon is unique as it represents a particular amino acid. The two major steps that take place in order for information to be passed through are discussed in detail below. Before we look at the process, let just have a brief introduction of the cell and the parts involved. The DNA is found in the nucleus, at the center of the cell. Transcription takes place in the nucleus; the DNA is transcribed into RNA. For you to understand the process, you must know the difference between DNA and RN. Here is a list of differences that may help you remove any misunderstanding between the two, (Hall 2011).DNA contains deoxyribose, but RNA contains ribose. Ribose has more –OH than deoxyribose that contain –H in the second carbon. DNA is composed of two strands, but the RNA has only one strand. DNA can handle alkaline environments, but RNA cannot. When it comes to their functions, the DNA stores and transmits genetic information. While the RNA carries messages, between the ribosomes and the DNA. The DNA has thymine, adenine, guanine and cytosine nucleotides. But RNA has cytosine, adenine, guanine and uracil.TranscriptionIt involves the replication of genetic material or information stored in the DNA to the RNA. Although the RNA sounds similar to the DNA, it only has a single strand. Only one strand of the DNA is required to from the RNA. It is called the antisense strand and is the only strand that the DNA uses during the transcription stage. The sense strand remains unused during the process. Also involved is the enzyme ligase. It role is to facilitate or make sure that DNA strands are joined, through catalyzing the creation of the bond phosphodiester. It also plays another significant role, repairing broken or damaged single strands, but only in animals with duplex DNA.

(Source http://www.shmoop.com/dna/dna-replication.html)
TranslationTranslation is the second stage. It takes place when the protein is created from the data or information obtained from the mRNA. The translation process involves reading of the mRNA using a series of genetic codes. The genetic codes are a set of rules or procedure that stipulates how the mRNA sequence will be translated into 20 different amino acids. The genetic code is composed of a combination of three nucleotides which, together from a codon. Every codon corresponds or is same with a particular amino acid, (Hyde 2010). The translation process happens in the ribosome, which acts as a factory for the production of protein. The ribosome is made up of small subunits, which are surrounding comprise of protein and ribosomal RNA. The transformation of the genetic information from the mRNA takes place in three stages. The first initiation, the subunits around the ribosome binds at the edge of the mRNA. The tRNA molecule with methionine, which is an amino acid, attaches to the first codon of the mRNA. The bigger subunits also bind to finish the initiation stage. The second process is the elongation, translation of the remaining codons continues. A long chain of the peptide bond is formed while the amino acid is being formed. This process continues up to the last remain codon id done. The termination stage takes place when the tRNA cannot recognize certain codon known as the stop codon. After which the ribosome figures it out that the process is complete. Then the protein formed is set free. The RNA synthesis is a process carried out by RNA polymerases, which are proteins. They transcribe the information from the DNA. It involves several stages, and the enzyme RNAP is an essential component. It helps in creating a similar RNA copy of a DNA, this is usually the stage in gene creation. Because the RNA polymerase is necessary during the life of a cell, it is a soft target to toxins and poisons. There many factors that can inhibit the action of the RNA polymerase and cause its nit to carry out it functions. One such factor is the alpha amanatin, which is found in the death cap mushroom. Briefly, the amanatin prevents inhibition and elongation from taking place during the transcription process.
It does this by directly preventing the conformational change of the enzyme, which is important for the transcription process. The amanatin binds on the RNA polymerase molecule just under the double helix extending far to the cleft, which is between two subunits. The amanatin then forms hydrogen bonds with the bridge of the doudle helix and the residues left by Rpb1.The interaction of the amanatin molecule with the RNA polymerase molecule means, that the translocation of the RNA polymerase along the DNA and RNA helix is inhibited. Research has shown that amanatin does not inhibit the formation of phosphodiester bonds. Nonetheless, the, the speed at which polymerase moves along the helix is reduced. Thus, by stopping translocation the active area is never empty, which causes the synthesis of messenger RNA to stop. When the death cap mushroom is ingested, the amanatin reacts RNA polymerase stopping the synthesis of the messengers RNA. The reason why this is bad for the body is because without the messenger RNA protein cannot be produced and as a consequence the production of new cells stops also. The major toxin mechanism is the inhibition of RNA polymerase II in DNA reproduction. The reason this becomes deadly is that this is a vital enzyme in the synthesis of the messenger RNA and without it, protein synthesis cannot happen and new cell production ceases. Without new cells being produced, the old once die out and the body cannot function, which results to organ failure and eventually the death of the victim. The liver and the kidney cells are the one most affected and this is why people who have eaten the mushrooms die of organ failure.
References
Hall, L. (2011). DNA and RNA. New York: Rosen Pub.
Hyde, N. (2010). DNA. St. Catharines, Ont: Crabtree Pub.

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