The amino acid sequence of a portion of a polypeptide is

Question

N...Cys-Pro-Ala-Met-Gly-His-Lys...C

Give the DNA template and coding strand sequences corresponding to the mRNA. Use the N, Pu, and Py symbols as placeholders.

Accepted Answer

Hey, everyone. Let's take a look at this question together. The sequence of A peptide is as follows. Using the genetic code table, identify the correct M R N A sequence and note that the abbreviation P U represents a pine and the abbreviation P Y represents a pyrimidine in that sequence of a peptide. And we have four different answer choices with different locations of that P and pyrimidine in the peptide. So we want to know which of the following answer choices represents the sequence of a peptide that we are given. So first, let's recall what a purine and a pyridine is. So we know that our purines are the bases adenine. And so that means that our pyridine include the base of diamine thine and uracil. And we also know from the sequence of a peptide that we are given. That we have the amino acids of methionine, lysine glutamic acid, arginine, crypto and serene. So using our genetic code table, we are able to see which codons code for all of the different amino acids that we have in our sequence of a peptide. And we know that methionine is our start codon, which is A U G or lysine. We can have the codons AAA or a A G or glutamic acid. We can have G A A or G A G arginine. We can have a few different codons. So we can have C G U C G C C G A C G G A G A and a G G crypto only has one codon which is U G G and lastly, serene also has several different codons. So we have U C U U C C, U C A U C G as well as a G U. And lastly A G C and now that we know all the different codons that can code for the different amino acids in our sequence of a peptide, we can go ahead and search through our answer choices to determine which one is the correct answer. So answer choices A through D are all similar up until we get to the number six position in the sequence where answer choices A B and C all contain a pine. But answer choice D has a pine. And since a U G is our start code on, that means that we have to determine what the second amino acid is, which we know is lysine and lysine can either be coated by AAA or A A G and A and G are both urines. So that means that answer choice D can be eliminated. And the next difference is in the third amino acid which we know is glutamic acid. And glutamic acid is coated by G A A or G A G, which we can see that the difference lies in that third base. Which answer choice is A and B contain a purine. And answer choice C contains a pyrimidine. And we note that glutamic acids third base is a pine. So that means answer choice C can be eliminated. And we have to determine between answer choice A and answer choice B which the next difference between answer choice A and answer choice B occurs in the seventh amino acid, which we know is crypto fan, which tritoon is only coded by one CODON, which is U G G. So answer choice choice A contains U G A and not U G G. So answer choice A can be eliminated leaving us with the correct answer, which is answer choice B, the correct M R N A sequence. Since answer choice B contains the correct M R N A sequence for our peptide and answer choices. AC and D are all incorrect. I hope you found this video to be helpful. Thank you and goodbye.

The amino acid sequence of a portion of a polypeptide is
N...Cys-Pro-Ala-Met-Gly-His-Lys...C
Give the DNA template and coding strand sequences corresponding to the mRNA. Use the N, Pu, and Py symbols as placeholders.

Key Concepts

Amino Acids and Polypeptides

DNA and RNA Transcription

Nucleotide Symbols (N, Pu, Py)

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