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Home  ›  The Base Sequence Of The Dna Template Strand Is T G C A A C-. What Is The Corresponding Mrna?

The Base Sequence Of The Dna Template Strand Is T G C A A C-. What Is The Corresponding Mrna?

Written By Wednesday, March 23, 2022 Add Comment Edit

A schematic shows two horizontal strands of DNA against a white background, one in the lower half of the image and one arcing in the upper half. A transparent green globular structure, representing the enzyme RNA polymerase, is bound to a several-nucleotide-long region along the lower DNA strand about 60% of the way from the left side. The sugar-phosphate backbone of the DNA strand is depicted as a segmented grey cylinder, whereas the sugar-phosphate backbone of the RNA strand is depicted as a segmented white cylinder. DNA nitrogenous bases are represented as blue, orange, red, or green vertical rectangles attached to each segment of the sugar-phosphate backbone; RNA nitrogenous bases are represented by blue, green, orange, and yellow vertical rectangles attached to each segment of the sugar-phosphate backbone. RNA polymerase synthesizes a complementary RNA strand, forming DNA-RNA pairs of orange-blue, red-green, blue-orange, or green-yellow, consistent with a thymine to uracil substitution in the RNA strand. About three dozen individual nucleotides float in the background. One individual nucleotide is visible inside the transparent enzyme at a higher magnification.

Figure two: RNA polymerase (green) synthesizes a strand of RNA that is complementary to the Deoxyribonucleic acid template strand below information technology.

Once RNA polymerase and its related transcription factors are in identify, the single-stranded Dna is exposed and gear up for transcription. At this signal, RNA polymerase begins moving down the Deoxyribonucleic acid template strand in the 3' to 5' management, and as it does so, it strings together complementary nucleotides. Past virtue of complementary base- pairing, this action creates a new strand of mRNA that is organized in the 5' to 3' direction. As the RNA polymerase continues down the strand of Dna, more nucleotides are added to the mRNA, thereby forming a progressively longer chain of nucleotides (Effigy ii). This process is called elongation.

A schematic compares a single-stranded DNA molecule with a single-stranded RNA molecule with a similar sequence. Both RNA and DNA contain nitrogenous bases, represented by vertical colored rectangles, attached to a sugar-phosphate backbone, represented as a segmented cylinder. There are two major differences between the composition of RNA and DNA strands. The sugar in the DNA strand is deoxyribose, represented by a grey cylinder, whereas the sugar in the RNA strand is ribose, represented by a white cylinder. In addition, the nitrogenous base thymine (red) in the DNA strand is replaced by uracil (yellow) in the RNA strand.

Effigy 3: Deoxyribonucleic acid (top) includes thymine (ruby); in RNA (bottom), thymine is replaced with uracil (yellow).

Three of the four nitrogenous bases that brand upward RNA — adenine (A), cytosine (C), and guanine (One thousand) — are also found in Deoxyribonucleic acid. In RNA, however, a base called uracil (U) replaces thymine (T) as the complementary nucleotide to adenine (Figure 3). This means that during elongation, the presence of adenine in the Deoxyribonucleic acid template strand tells RNA polymerase to attach a uracil in the corresponding expanse of the growing RNA strand (Effigy 4).

A schematic shows two rows of nucleotides. Each individual nucleotide is represented as an elongated, vertical, colored rectangle (a nitrogenous base) bound at one end to a grey horizontal cylinder (a sugar molecule). The top row of nucleotides is from RNA, with an A-C-U-G base sequence. The bottom row of nucleotides is from DNA, with a T-G-A-C base sequence.

Figure 4: A sample section of RNA bases (upper row) paired with Dna bases (lower row). When this base-pairing happens, RNA uses uracil (yellow) instead of thymine to pair with adenine (green) in the DNA template beneath.

Interestingly, this base substitution is not the simply difference between DNA and RNA. A second major difference betwixt the ii substances is that RNA is made in a single-stranded, nonhelical form. (Recollect, Dna is well-nigh ever in a double-stranded helical class.) Furthermore, RNA contains ribose saccharide molecules, which are slightly unlike than the deoxyribosemolecules found in DNA. As its name suggests, ribose has more than oxygen atoms than deoxyribose.

Thus, the elongation period of transcription creates a new mRNA molecule from a single template strand of DNA. Every bit the mRNA elongates, it peels away from the template every bit it grows (Figure 5). This mRNA molecule carries Deoxyribonucleic acid'southward message from the nucleus to ribosomes in the cytoplasm, where proteins are assembled. However, earlier it can do this, the mRNA strand must separate itself from the Dna template and, in some cases, information technology must also undergo an editing process of sort.

A schematic shows two strands of DNA against a white background, each going from the lower left to the upper middle of the frame. A transparent green globular structure, representing the enzyme RNA polymerase, is bound to a several-nucleotide-long region along the lower DNA strand. The sugar-phosphate backbone of the DNA is depicted as a segmented grey cylinder. Nitrogenous bases are represented as colored vertical rectangles attached to each segment on the sugar-phosphate backbone. A newly synthesized RNA strand is shown in the foreground of the illustration. It snakes down to the RNA polymerase. In the RNA strand, uracil, represented by a yellow base, has been inserted in place of thymine.

Figure 5: During elongation, the new RNA strand becomes longer and longer as the Deoxyribonucleic acid template is transcribed. In this view, the v' end of the RNA strand is in the foreground. Note the inclusion of uracil (yellow) in RNA.

Source: https://www.nature.com/scitable/topicpage/the-information-in-dna-is-decoded-by-6524808/?error=cookies_not_supported&code=d2164b96-da33-4c24-8838-9f4ec060e883

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