Expert: Walter Hintz - 1/24/2009

Question
QUESTION: hi
i am a second secondary student and i have a few questions for u!!!
first could u explain to me the role of RNA and MRNA and TRNA and the codons and anticodons?
also could u explain to me how the identification of of the chemical constituents of protiens using chromotography tank works?
third i know that there are 20 kinds of amino acids but is every protein is made of 20 amino acids in different sequences ?? i mean can there be a protein made up of 15 amino acid for example
i wanna know how insulin is manufactured in the body and how it becomes active
and i wanna know how protein is synthesized and everything that goes on in the dna and rna and mrna and trna so that the protein is synthesized
thnx a lot for the help

ANSWER: You have so many questions here that it would take me pages to answer. In fact I would cover this material in about 3-4 Lectures in my biology classes. Pick out a single question that you are having trouble with.  Read all about it and then let me know what there is about it that you do not understand.  Use my emali to get back to me (waltjh@sbcglobal.net)

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QUESTION: can u at least answer my question regarding the relation between protein synthisis and RNA MRNA TRNA plzz

Answer
Sure. DNA replicates a strand of mRNA according the base pairing rule   A-U G-C T-A and C-G.  The strand of mRNA sttaches to the ribosomes on the rough ER. The necleotides (AUGC) realigned into groups of three with each representing a codon for a specific amino acid.  A second piece of RNA called transfer RNA (tRNA) is an anti codon and picks up the amino it codes for and returns it to the mRNA template. The amino acids are then joind with peptide bonds forming a polypeptide and it breaks away.   Looka my diagram here

DNA          A A C C A T T G A C G A
mRNA          U U G G U A A C U G C U
tRNA          A A C C A U U C A C G A

Amino Acid    Gly val thr iso  gly*
 * these are  probably not the amino acids the mRNA codes for but I did not have a code sheet handy
 Note that this sequence of DNA directs the specific protein.  If a single nucleotide is different the protein is different