Sunday, November 24, 2019

Central Dogma essays

Central Dogma essays Part of DNA sequence are transcribed into RNA A specific part of the cells DNA ntide sequence i.e. a gene is copied into an RNA nucleotide sequence. The info in RNA although in another chemical form is still essentially in same language as DNA. This is T. Both DNA and RNA are linear polymers of 4 different types of ntides subunits linked together via phosphodiester bonds. However RNA differs from DNA in that it contains ribose sugar and base uracil instead of thymine. Both U and T can hydrogen bond to adenine. Despite small differences, RNA and DNA are quite similar in overall structure, DNA being double stranded and RNA single and can therefore fold into a variety of shapes giving proteins. T gives RNA Complementary to one DNA strand. All RNA in cell is through DNA T. Steps include; 1.Opening and unwinding of small portion of DNA helix to expose bases on each DNA strand. 2. One of the two strands acts as templates for RNA molecules synthesis. 3. Like DNA replication, Ntide sequence for RNA is determined by complementary base pairing between incoming nucleotide and DNA template. Once a good match, incoming ribonucleotide is covalently linked to growing RNA chain in an enzymatic catalyzed reaction. RNA transcript is therefore elongated one nucleotide at a time and has a nucleotide sequence complementary to DNA. 1. Unlike a newly formed DNA strand, RNA strand doesnt remain Hydrogen bonded to DNA template strand. Instead, just behind region where ribonucleotides are being added, RNA chain is displaced and DNA helix re-forms. Therefore RNA molecules from T are released from DNA template as single strands. 2. Also, since they are copied from a limited region of DNA, RNA molecules are much shorter than DNA molecules. 3. DNA molecule in human chromosome can be made up to 250million nucleotides long, whereas most RNAs are no more than a few nucleotides long and even shorter. RNA polymerase p...

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