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The molecules responsible for reading the language of amino acids and nucleotides is:

  • RNA polymerase enzyme
  • mRNA
  • tRNA
  • DNA

I don't actually understand what "reading amino acid language" means! Does saying nucleotides refer to those on the DNA molecule? If so then RNA-polymerase is then responsible for synthesizing mRNA molecules which carries the same genetic code of the amino acids; or is it something else?

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    $\begingroup$ Is this a homework question? I guess that "amino acid language" refers to the genetic code, en.wikipedia.org/wiki/Genetic_code $\endgroup$ – Roland Mar 1 '17 at 10:48
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    $\begingroup$ This is a homework question I assume? You should show what effort you've made so far to be well received on the site. I agree it's not very well worded, however. My interpretation is that you can think of the question as asking you: "What molecule is responsible for converting between the 'code' of DNA and the 'code' of Amino Acids" $\endgroup$ – Joe Healey Mar 1 '17 at 10:48
  • $\begingroup$ It means which molecule participates in the process of turning a sequence of nucleotides into amino acids, i.e. "reads" the sequence of nucleotides and "knows" to which amino acids it corresponds. $\endgroup$ – Don_S Mar 1 '17 at 10:53
  • $\begingroup$ It is not a homework question unless studying for un upcoming exam is considered a homework question.... sorry for any inconvenience and thank you $\endgroup$ – Jasmin Badawy Mar 1 '17 at 11:03
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    $\begingroup$ Yeah, that’s one badly worded question! I’m assuming that the required answer is one/all of: ribosome/tRNAs/aminoacyl tRNA synthetase. However, this would actually be inaccurate or even wrong: these molecules read the codon language, not the amino acid language. I’m not aware of any molecule which actually reads amino acids, except maybe immunoglobulins. However, I’ve never heard of “language” in this context. Another candidate would be post-translational modification (e.g. glycosylation). But, once again, I don’t know of anything that would qualify that as a language. $\endgroup$ – Konrad Rudolph Mar 1 '17 at 17:04
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Clarifying the premise

As mentioned in my comment, the term “amino acid language” doesn’t really make sense as far as I’m concerned. Worse: nothing, to my knowledge, is ever reading an amino acid sequence in living systems.

Yet here we are. The term “amino acid language” itself is definitely used (though, once again, I’ve never heard of anything “reading” this language).

So, to answer the question, let’s define a meaning for the term “amino acid language”:

The amino acid language is a language written by amino acids. In other words, a set of sequences consisting of amino acids.

The candidates

Now, your question is multiple choice so it’s sufficient to go through all possible choices and see if they fit:

  • RNA polymerase enzyme

RNA polymerase reads either DNA (DNA-dependent RNA polymerase) or RNA (RNA-dependent RNA polymerase) and produces RNA. There are no amino acids involved. This is clearly not the right answer.

  • mRNA

mRNA is an information-carrying molecule. But it does not “read” anything (at least not in its canonical function). Note that other RNAs are involved in recognising/reading things, but not mRNA. So, not the answer.

  • tRNA

tRNAs (transfer RNAs) are RNAs that carry individual amino acids. Each individual tRNA recognises a codon on an mRNA via complementary base pairing and thus “translates” the codon into a specific amino acid by the rules of the genetic code. In the context of this question, it’s fair to say that tRNAs (in combination with other molecules) are writing the amino acid language.

  • DNA

DNA, like mRNA, is an information-carrying molecule that does not read anything. Moving on.

The answer

tRNAs do not read amino acids in the conventional meaning of the phrase. But it’s the closest candidate here: not only does it indeed read a language, it translates symbols into amino acids. This is therefore almost certainly the expected answer, unless an acceptable answer is “none of the above”.

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  • $\begingroup$ Thank you for your effort..... This was really confusing as I got like 3 different answers from 3 different people and I never actually came across the word reading an amino acid language which made the question far more confusing... thanks again. $\endgroup$ – Jasmin Badawy Mar 1 '17 at 17:38
  • $\begingroup$ I think what the question was trying to get at, though I agree it was poorly written, is that the "codes" in DNA, RNA polymerase, and mRNA have no direct connection to the amino acids; when we say a given sequence "codes for" a particular amino acid, the only thing mediating that code, connecting it to a particular amino acid, is the tRNA (though the aminoacylation process is at least if not more important). $\endgroup$ – Bryan Krause Mar 1 '17 at 17:49

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