Top-Rated Free Essay
Preview

DNA transcription

Good Essays
530 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
DNA transcription
The upper most strand is the (coding strand) DNA base sequence (triplet) of the gene codes for synthesis of a particular polypeptide chain. The second strand is the mRNA base sequence (template strand used for copying) codon of the transcribed mRNA. The process for going from the upper stand to the second strand is called Transcription and involves an enzyme called polymerase. The polymerase attaches to the promoter region (start codon) and reads the nucleotide base sequence until it gets to a termination signal (stop codon) and then it jumps off because it has the whole recipe copied. The polymerase uses complimentary base pairing to attach RNA nucleotides to the second strand with the exception that it attaches Uracil in place of Thymine. The row of “guitars” represent the transfer RNA (tRNA) which transfers a specific active amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation. Each tan ball in the diagram represents an amino acid. The multi-color “piano keys’ represent the four nucleotide bases A, G, T, and C. In the (first) upper stand the A, G, T, and C bases are grouped into a sequence of three, called a triplet. Each triplet specifies a particular amino acid. The second strand contains RNA which differs from DNA because it is single stranded and it has the sugar ribose instead of deoxyribose, and the base uracil (U) instead of thymine (T). Unlike DNA, the messenger RNA (mRNA) leaves the nucleus through the nuclear pore into the cytosol and attaches to a ribosome to undergo translation (tRNA). The difference between mRNA and tRNA is that the mRNA codon is the complimentary base pairing of the DNA triplet, whereas tRNA is an anticodon, a three-base sequence opposite complementary base pairing of the mRNA codon. The anticodon is identical to the template DNA sequence except for the substitution of uracil (U) for thymine (T). In the translation step of protein synthesis (going from second strand to the “guitars”) the language of nucleic acids (base sequence) is translated into the language of proteins (amino acid sequence). The mRNA leaves the nucleus through the pore into the cytosol where it attaches to a ribosom. Specialized enzymes activate and assemble a large and small ribosomal subunit. Using the rules referred to as the genetic code, the ribosome reads the codons and matches them with the corresponding anticodon. Energized by ATP, the correct amino acid is attached to each species of tRNA by aminoacyl-tRNA synthetase enzyme. The ribosom has three active sites A, P and E. Translation starts when the incoming aminoacyl-tRNA recognizes the complementary codon calling for it at the A site on the ribosome. It forms a hydrogen bond with the codon via its anticodon. The ribosome travels along the mRNA and each codon is read in sequence and a new amino acid is added to the protein chain, then the tRNA in the A site is moved to the P site. Once the amino acid is released from the P site, tRNA then leaves through the E site released to reenter the cytoplasm. The polypeptide is released when the stop codon is read.

You May Also Find These Documents Helpful

  • Satisfactory Essays

    a) Assume that RNA polymerase will read the top strand of DNA as the “template” to synthesize mRNA. What will be the sequence of the mRNA synthesized? (3 points)…

    • 276 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    RNA: RNA is similar to DNA except that instead of deoxyribose as the sugar, it has ribose. It is single stranded, and instead of thymine, there is uracil. There are 3 forms involved in polypeptide synthesis:mRNA: Messenger RNA carries the genetic code outside the nucleus, into the cytoplasm, where it can be read by ribosomestRNA: Transfer RNA carries the amino acids to the ribosomes to link and form a polypeptide chain. tRNA are shaped like clover leaves; there is a different type for every amino acid. At the bottom of every tRNA molecule is an anti-codon that binds to the codon on the mRNA strand. That is how the amino acid is linked to the codon.…

    • 7073 Words
    • 23 Pages
    Good Essays
  • Good Essays

    During transcription, the information in the DNA of a specific gene is copied into mRNA (messenger RNA), which creates a nucleotide sequence. After transcription, if the DNA base sequence is 3’-TACCCTTTAGTAGCCACT-5’, then the base sequence of mRNA would be 5 '-AUGGGAAAUCAUCGGUGA-3’.…

    • 565 Words
    • 3 Pages
    Good Essays
  • Good Essays

    Agr 3303 Exam 2

    • 2117 Words
    • 9 Pages

    1. The primary structure of a protein represents: (*) the amino acid sequence. (2) the functional configuration. (3) the subunits of a protein. (4) a pleated sheet. (5) a alpha helix. 2. In prokaryotes, most genes are organized into operons. One component of an operon is the structural genes. Which of the following best describes a structural gene? (*) a sequence of DNA that specifies a polypeptide. (2) a sequence of DNA that produces tRNA's. (3) a sequence of DNA that interacts with the small ribosomal subunit. (4) a sequence of DNA that is recognized by RNA polymerase. (5) a sequence of DNA that is involved in forming the structure of a double helix molecule. 3. Identify the correct sequence of steps in protein synthesis in prokaryotes: A - binding of large ribosomal subunit to initiation complex B - peptide bond formation C - binding of mRNA to small subunit of ribosome D - binding of charged tRNA to A site E - release of fmet-tRNA and translocation (1) B, C, A, D, E (2) B, E, C, A, D (3) C, E, B, A, D (*) C, A, D, B, E (5) C, D,…

    • 2117 Words
    • 9 Pages
    Good Essays
  • Satisfactory Essays

    Dna Synthesis Lab Report

    • 268 Words
    • 2 Pages

    TRANSCRIPTION: Transcription is the process of which DNA matches corresponding RNA bases, Transcription is located in the Nucleus, and the only type of RNA that is involved in Transcription is mRNA, and the purpose is so that the code can get out of the Nucleus, mRNA is also made through Transcription, It also takes information that doesn't directly make proteins but it helps makes codes for the production of proteins, DNA Transcription consist of 4 nucleotide bases, Adenine, Thymine, Cytosine, Guanine. Transcription also unwinds the strand of DNA and the RNA comes in and matches then becomes a single strand. The only thing that changes during this process is the Thymine gets replaced with Uracil.…

    • 268 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Dna Sci/230

    • 494 Words
    • 2 Pages

    DNA stands for Deoxyribonucleic acid and looks like a spiral. The spiral is also known as a double helix. The strands are made up of our genetic information, composed of genes and chromosomes. There are four bases divided among purines and pyrimidines. On the purines there are Adenine (A) and Guanine (G). On the pyrimidines there are Cytosine (C) and Thymine (T). The base pairs are Adenine and Thymine (A-T) and Cytosine and Guanine (C-G). DNA is found in the nucleus of every human cell. Humans have 46 chromosomes. When a cell reproduces, the chromosomes get copied and distributed to each offspring.…

    • 494 Words
    • 2 Pages
    Good Essays
  • Good Essays

    1. Describe the three parts of a nucleotide and how they bond to form a nucleotide.…

    • 877 Words
    • 4 Pages
    Good Essays
  • Satisfactory Essays

    Sci 230 Dna

    • 490 Words
    • 2 Pages

    DNA is composed of two polynucleotide strands wound together into a structure known as a double helix. Each nucleotide consists of a sugar base .Nucleotides form together creating a sugar phosphate backbone to each strand. There are three forms of DNA that differ significantly. The most common, B form, is the structure most people have heard of. It consists of the right handed double helix, with a large major groove and a smaller but accessible minor groove. These grooves are spaces between the backbones which allow access to the bases for interactions with proteins. A form DNA is also a right handed helix, but as yet has not been found in organisms, and only exists in synthetic environments. It has a wider, flatter structure. Z form DNA is found in living organisms, but is a left handed helix, meaning it twists in the opposite direction.…

    • 490 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Dna Worksheet

    • 361 Words
    • 2 Pages

    The flow of information starts with transcription. Within transcription, the DNA molecule holds a nucleotide sequence called the promoter that the RNA polymerase attaches to and begins the RNA synthesis. Through the process of transcription, the RNA strand becomes longer and finally detaches from the DNA strand, wherein the two DNA strands come back together forming the previously continuous strand. At this point the RNA turns…

    • 361 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    dna worksheet

    • 380 Words
    • 2 Pages

    DNA is typically has two strands running in opposite direction and is usually referred to as a double helix. Each on the individual strands consists of a backbone that is formed by sugar molecules linked together in groups. Each individual sugar molecule is covalently linked to one of the following possible bases: Adenine, Guanine, Cytosine and Thymine. These bases are typically aligned perpendicular to the axis of the strand. As previously stated the strands run in opposite directions with the bases paired up with Adenine always with Thymine and Guanine always with Cytosine. Theses pairs form hydrogen bonds with the A/T pair having 2 and the G/C pair having 3. The extra hydrogen bond makes the G/C pair stronger.…

    • 380 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Dna Worksheet

    • 472 Words
    • 2 Pages

    The genotype is the genetic makeup of a cell, an organism, or an individual, Where as a…

    • 472 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    Dna Work Sheet

    • 491 Words
    • 2 Pages

    Describe the structure of DNA.DNA is thread formed by two strands, related together to form a double helix. The double helix looks like a twisted ladder. The sides of this ladder are long unites called nucleotides and are made of three parts; a nitrogenous base, a sugar, and a phosphate group. The sides of the ladder or the nucleotides from the two separate strands of the DNA are attached by an appendage made of one of four separate bases. These appendages represent the rungs of the DNA ladder and are attached to the complimentary strand of the DNA. The bases or rungs are made of either Adenine (A) OR Thymine (T) or Cytosine (C) and Guanine (G). The attachment of the strands by the bases is specific Adenine can only join with Thymine, and Cytosine can only join with Guanine. Since this base pairing is specific, if one knows the sequence of bases a long one strand of the DNA one will also know the strand of the DNA one will also know the sequence along the complimentary strand.…

    • 491 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Dna Worksheet

    • 459 Words
    • 2 Pages

    The flow of information from gene to protein is based on the triplet code. The genetic instructions for the amino acid sequence of a polypeptide chain are written in DNA and RNA as a series of three-base words called codons. The three-base codons in DNA are transcribed into complementary three-base codons in RNA, and then the RNA codons are translated into amino…

    • 459 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    The mRNA encodes the amino acid sequence of a protein. During the translation, ribosomal RNA combines with other proteins to form a ribosome which amino acids are transported to the ribosome. The combination of mRNA and tRNA converts the mRNA into the amino acid sequence of the protein.…

    • 438 Words
    • 2 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Anatomy Practice

    • 344 Words
    • 2 Pages

    The uppermost strand in this structure is called the coding strand. The second strand that lies below the coding strand is called the template strand. In order for a RNA polymerase to go from the upper strand to the second strand it must go through the process called transcription. First, the RNA polymerase must attach on to one of the genes on the coding strand on DNA. Once the RNA polymerase attaches, it must then begin the process called initiation. This means that the RNA polymerase opens up both strands of DNA in order for mRNA synthesis to begin as it moves down the template strand. Once it starts moving down the template strand, that’s when elongation occurs. This is when the RNA polymerase unwinds the DNA helix in front of it and rewinds the helix behind it matching each base with its correct partner. Once the RNA polymerase reaches a special base sequence called termination signal, transcription is then over. This is called termination. The row of “guitars” represents the sequence in the tRNA anticodons. The tan balls on the bottom of the “guitars” represent the amino acids in the polypeptide chain. The multi-color piano keys represent the different bases that are in DNA and RNA molecules. What is different in the second strand than the first upper strand is that the second strand is mRNA which contains the base Uracil while the first strand is DNA and contains Thymine instead of Uracil. The difference between the second strand and the “guitars” is that the second strand is mRNA which are codons while the “guitars” are tRNA and are anticodons. The difference in the sequence between the first strand and the “guitars” is that the first strand is triplets which contain Thymine and the “guitars” are anticodons and instead of Thymine, they contain Uracil. The process going from the second strand to the “guitars” is called translation. This is where the language of nucleic acids is translated into the language of proteins in which they are used to assemble…

    • 344 Words
    • 2 Pages
    Satisfactory Essays