What Makes Protein Synthesis

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.

Encoded DNA within the nucleus is transported to small molecules of nucleic acid named messenger RNA (mRNA)

2) The mRNA exits through the pores in the nuclear envelope and travels to the cytoplasm, where it then binds to ribosomes.

Since DNA has the instructions for making protein we usually wonder how is it able to make ribosomes if DNA is stored within the nucleus. This is when a handy tool comes in called transcription and copies the DNA into mRNA so it can be reached outside of the cell.

Translation is a task that makes ribosomes synthesize proteins utilizing mRNA transcript made during transcription. In the begining of this task mRNA attaches it self to a ribosome so that it can be reveal a codon (three nucleotides).

Inside the nucleus is the nucleolus which produces ribosomes. The ribosomes then transport out of the nucleolus and to the rough endoplasmic reticulum for a process called protein synthesis. (Plant Cell Anatomy, n.d.)

Transcription is a process in which genetic information from DNA is encoded onto messenger RNA, by unwinding the DNA and splicing exons and introns and coding them onto the mRNA so the DNA itself is not used directly. Translation is a process by which ribosomes reads the mRNA to determine the amino acid sequence of the protein.

(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.

At the end of this unit, students will be able to use the terms DNA, RNA, protein, and nucleotide when it comes to protein synthesis. They will be able to explain how transcription and translation are processes of protein synthesis. They will be able to use genetic code table to translate an RNA sequence into an amino acid sequence. Students will be able to demonstrate their understanding of the Central Dogma. They will be able to describe the semi-conservative nature of DNA replication. They will be able to explain how a change in the DNA sequence code can alter protein function.

During the process of transcription, the information stored in a gene's DNA is transferred to a similar molecule called RNA (ribonucleic acid) in the cell nucleus. Both RNA and DNA are made up of a chain of nucleotide bases, but they have slightly different chemical properties. The type of RNA that contains the information for making a protein is called messenger RNA (mRNA) because it carries the information, or message, from the DNA out of the nucleus into the cytoplasm.

Transcription. In this process, the information from the DNA sequence is copied to a complementary RNA sequence. The type of RNA that is involved in this process is the messenger RNA (mRNA). During a transcription process, when a sequence of DNA is expressed, one of the two DNA strands is copied into the mRNA based on the base-pairing rules. For example, in base-pairing in DNA, Adenine (A) is paired with Thymine (T), and Cytosine (C) is paired with Guanine (G.

Ribosomes- This is a tiny particle made up from RNA and a large number of proteins found in the cytoplasm. Ribosomes bind to messenger RNA and then synthesises proteins.

Transcription is where DNA is transcribed into RNA which then can be pass to the ribosome’s to act as a template for protein synthesis. Before transcription can begin DNA must unwind and the two halves of the molecule much come apart so exposing the base sequence. This process begins when a region of a two DNA strands is unzipped by enzyme called RNA polymerase attaches to the DNA molecule at the imitation site.

The formation of a protein begins in the genes, which contain the basic building information for all parts of living organisms. There are four DNA nucleotides that make up genes: A, T, C, and G. A codon is any arrangement of three of these nucleotides. Each triplet of nucleotides codes for one amino acid. First transcription will begin in the nucleus where mRNA will transcribe the DNA template. During both transcription and translation, there are three steps. The first step in transcription is initiation where RNA polymerase separates a DNA strand and binds RNA nucleotides to the DNA. RNA nucleotides are the same as DNA ones except that U replaces the T. The second is just the elongation of the mRNA. The third step of transcription is termination. This occurs when RNA polymerase reads a codon region and the mRNA separates from the

AUTHORS: Benjamin J Des Soye, Jaymin R Patel, Farren J Isaacs and Michael C Jewett