Codons
Biology discussion, revision, exam and homework help.
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CodonsAre 3 nucleotide bases in DNA a codon or is that just a base triplet and it is only a codon in mRNA? My book doesn't really differentiate whether a base triplet in DNA is called a codon or not.
Last edited by TheBlueNowhere; 02-06-2012 at 21:17. -
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Re: Codonsit is called a codon. ever heard of a website called wikipedia(Original post by TheBlueNowhere)
Are 3 nucleotide bases in DNA a codon or is that just a base triplet and it is only a codon in tRNA and mRNA? My book doesn't really differentiate whether a base triplet in DNA is called a codon or not.
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Re: CodonsYeah it's a codon...3 bases that code for an amino acid(Original post by TheBlueNowhere)
Are 3 nucleotide bases in DNA a codon or is that just a base triplet and it is only a codon in tRNA and mRNA? My book doesn't really differentiate whether a base triplet in DNA is called a codon or not. -
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Re: CodonsWell I googled it and this website came up (which I'd presume would give a more concise answer than wikipedia):
http://www.biology-online.org/dictionary/Codon
This suggests that it is only called a codon in mRNA since it defines it as a set of 3 adjacent nucleotides in mRNA (with no mention of DNA) which is what made me unsure of whether a base triplet in DNA is a codon.Last edited by TheBlueNowhere; 02-06-2012 at 21:18. -
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Re: CodonsI should've worded it better since tRNA was irrelevant in the question I asked (as well as being wrong the way I wrote it), I've edited it now.(Original post by Vamp1reWeekend)
Yeah it's a codon...3 bases that code for an amino acid -
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Re: CodonsThey are essentially the same thing (DNA and RNA codons) although in RNA you obviously have T substituted for U, therfore a huge number of RNA codons contain uracil and so it wouldnt really make sense to talk about codons in reference to DNA. I'm not really sure in what context you would neet to be talking about codons in reference to DNA though :/(Original post by TheBlueNowhere)
Well I googled it and this website came up (which I'd presume would give a more concise answer than wikipedia):
http://www.biology-online.org/dictionary/Codon
This suggests that it is only called a codon in mRNA since it defines it as a set of 3 adjacent nucleotides in mRNA (with no mention of DNA) which is what made me unsure of whether a base triplet in DNA is a codon. -
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Re: Codons3 nucleotide bases are a codon. Base triplet is another word. m-RNA has an anticodon as "head" (with three bases) which are connect to a codon, which belong to a DNA strand. Anticodon and codon are connected when m-RNA (with amino acid) arrive the ribosome, so a chain of protein can be created by amino acids. Anything else?(Original post by TheBlueNowhere)
Are 3 nucleotide bases in DNA a codon or is that just a base triplet and it is only a codon in mRNA? My book doesn't really differentiate whether a base triplet in DNA is called a codon or not.Last edited by Kallisto; 02-06-2012 at 21:34. -
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Re: CodonsDein Englisch wird immer besser!(Original post by Kallisto)
3 nucleotide bases are a codon. Base triplet is another word. m-RNA has an anticodon as "head" (with three bases) which are connect to a codon, which belong to a DNA strand. Anticodon and codon are connected when m-RNA (with amino acid) arrive the ribosome, so a chain of protein can be created by amino acids. Anything else?
Your biology, however, is wrong in this case
A codon only applies to a sequence of 3 nucleotides in a molecule of mRNA.
A sequence of 3 nucleotides in a DNA molecule is known as a triplet.
At a ribosome, the mRNA codon binds to the tRNA anti-codon (which is complementary to the mRNA codon).
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Re: CodonsThanks for your praise!
oh, nooooooo!(Original post by thegodofgod)
D
(...)Your biology, however, is wrong in this case
A codon only applies to a sequence of 3 nucleotides in a molecule of mRNA.
(...)
of course, you are right! that is so embarrassing... 
m-RNA is created when transcription was happen by enzymes to "copy" DNA, right? it is a translation from language of bases to language of amino acid, right? as far as I know m-RNA copied DNA, because DNA is not able to leave the nucleus, right too? and then m-RNA is going to cytoplasm and is waiting on t-RNA, so last but not least proteins could be created by a ribosome. Right?
I know that was not an extensive explanation, but I would love to define what m-RNA is.Last edited by Kallisto; 03-06-2012 at 21:48. -
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Re: CodonsBitte schön!(Original post by Kallisto)
Thanks for your praise!
oh, nooooooo! of course, you are right! that is so embarrassing...
m-RNA is created when transcription was happen by enzymes to "copy" DNA, right? it is a translation from language of bases to language of amino acid, right? as far as I know m-RNA copied DNA, because DNA is not able to leave the nucleus, right too? and then m-RNA is going to cytoplasm and is waiting on t-RNA, so last but not least proteins could be created by a ribosome. Right?
I know that was not an extensive explanation, but I would love to define what m-RNA is.
Basically, what you've said is correct
You start off with DNA. DNA is separated to two separate strands by DNA helicase. There are free RNA nucleotides (A, C, G, U) in the nucleus, where the DNA is. This is when you get complementary base pairing (via hydrogen bonding) between RNA bases and DNA bases, forming a strand of mRNA by RNA polymerase. The DNA and mRNA strands then break away from each other, and the initial two DNA strands join again via hydrogen bonding.
The mRNA strand now exits the nucleus and enters the cytoplasm through the nuclear pores. At a ribosome, one mRNA codon binds via complementary base pairing and hydrogen bonds to the specific tRNA anti-codon, bringing the specific amino acid along with it. These amino acids join via condensation reactions to form a polypeptide.
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Re: CodonsI figured as much! but you forgot precusor m-RNA which consist of both exons and introns. After splicing, in which introns were separate from precusor m-RNA, m-RNA is created by exons. If you explain all kinds of facts in terms of genetic, then you mustn't forget any thing in your explanation in my opinion.(Original post by thegodofgod)
Bitte schön!
Basically, what you've said is correct
You start off with DNA. DNA is separated to two separate strands by DNA helicase. There are free RNA nucleotides (A, C, G, U) in the nucleus, where the DNA is. This is when you get complementary base pairing (via hydrogen bonding) between RNA bases and DNA bases, forming a strand of mRNA by RNA polymerase. The DNA and mRNA strands then break away from each other, and the initial two DNA strands join again via hydrogen bonding.
The mRNA strand now exits the nucleus and enters the cytoplasm through the nuclear pores. At a ribosome, one mRNA codon binds via complementary base pairing and hydrogen bonds to the specific tRNA anti-codon, bringing the specific amino acid along with it. These amino acids join via condensation reactions to form a polypeptide.
Last edited by Kallisto; 04-06-2012 at 11:57.
