Five Nucleotide Bases: C, T And U.

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.

3) As a ribosome moves along the mRNA, the genetic message is translated into a protein with a specific amino acid sequence.

The four bases found in DNA are adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T). A fifth pyrimidine base, called uracil (U), usually takes the place of thymine in RNA and differs from thymine by lacking a methyl group on its ring.

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).

The four names of the nitrogenous bases of the DNA are adenine, thymine, guanine, and cytosine. The word "adenine" was created in the 19th century in German from the Greek words “adēn” "gland" and "in". The word "cytosine" was coined in the 19th century from the German word "cytosin" from cyto- "cell", -ose and the chemical suffix -ine. The word "guanine" comes from the English words "guano" and "ine" and was also created in the 19th century. The word “thymine” comes from words “thymus” and the suffix -ine.

A Matching—Nucleotides: DNA and RNA 1. A 2. F 3. D 4. C 5.

A and G contain 2 rings and are referred to as purines whereas C and T contain one ring and are referred to as pyrimidines. 2 of those strands combine along to make the acquainted double helix structure of DNA. the 2 strands link to every alternative via interaction between the bottom pairs in a very extremely specific method. A solely pairs with T and C solely pairs with G. This specificity, called complementary base pairing, arises via hydrogen bonds. every C-G pairing involves 3 hydrogen bonds between the bases, whereas every A-T bond involves solely 2 hydrogen bonds leading to a weaker interaction.

In UNIT 7 you learned about the basics structure as well as the basic functions of deoxyribonucleic acid. You learned that deoxyribonucleic acid carries an “instruction manuel” to produce proteins that are responsible for passing traits from your parents to you. As you demonstrated in the previous activity, deoxyribonucleic acid is made of four nucleotides base pairs: adenine, thymine, cytosine, and guanine. They are often abbreviated as A, T, C, and G. The uniqueness of deoxyribonucleic acid is not particularly in just these 4 subunits, but how they are arranged. In this activity you will recreate protein synthesis.

Two scientists from Cambridge University named James Watson and Francis Crick were the first ones to actually build the actual structure of the DNA molecule. In building their DNA molecule, they discovered that there were two different types of bases, purines and pyrimidines. Purines were the larger of the two types of bases, and are the double ringed structures [example of nucleotides that fit in this category are adenine (A) and guanine (G)]. Pyrimidines were the smaller of the two types of bases, and are the only single ringed structures [example of nucleotides that fit in this category are cytosine (C) and thymine (T)]. The two scientists also discovered that in the DNA molecule, only two base pairings of nucleotides are possible, adenine (A) with guanine (G) and thymine (T) with cytosine (C). This is because of the improper forming of hydrogen bonds. In a G-C pairing, three hydrogen bonds are formed whereas in an A-T pairing, only two hydrogen bonds are formed.

A stable DNA structure is formed when the two strands are a constant distance apart. This can only occur when a purine (A or G) on one strand is paired with a pyrimidine (T or C) on the other strand. The purine A can only pair up with the pyrimidine T and the purine G can only pair up with the pyrimidine C. Each letter corresponds to a specific nucleotide base. (Wexler 2) A nucleotide is any part of a group of molecules that, when linked together, form the building blocks of DNA or RNA.

(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.

DNA consists of two strands. One is the coding strand and the other is the template stand. In transcription there is an enzyme called RNA polymerase that ‘unzips’ the two strands. This allows RNA nucleotides (uracil, adenine, guanine and cytosine) to enter the DNA and connect to the corresponding DNA nucleotides (thymine, adenine, guanine and cytosine) on the template strand. After the nucleotides have been paired, phosphodiester bonds, bond the RNA nucleotides together and this creates a continuous strain of mRNA which is capable of leaving the cell’s nucleus, whereas the DNA cannot as the molecule is too big. Once the mRNA has moved out of the nucleus it moves to a ribosome. (1)

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