Given below is the sequence of the mRNA ready for Translation"
5' - AUG CUA UAC CUC CUU UAU CUG UGA - 3'
a) what is the first codon technically known as and which amino acid does it code for?
b) how many amino acid residues will make the polypeptide chain corresponding to this amino acid? write the number of t-RNA molecules needed to translate the polypeptide chain?
c) write the sequence of the DNA strand that coded for the above mRNA
a) Start codon , Methionine
b)
c) 3' TAC GAT ATG GAG GAA ATA GAC ACT 5'
a) The first codon, AUG, is technically known as the "start codon". It codes for the amino acid methionine.
b) To determine the number of amino acid residues in the polypeptide chain, we need to count the number of codons (excluding the start codon). In this case, there are 8 codons in the sequence. Since each codon represents one amino acid, there will be 8 amino acid residues in the polypeptide chain.
To translate the polypeptide chain, we need one tRNA molecule for each codon. Therefore, we would need 8 tRNA molecules to translate the polypeptide chain.
c) To find the DNA strand that coded for the given mRNA sequence, we need to reverse the process of transcription.
The rules for converting mRNA to DNA are as follows:
- Replace each occurrence of "A" with "T".
- Replace each occurrence of "U" with "A".
- Replace each occurrence of "C" with "G".
- Replace each occurrence of "G" with "C".
Using these rules, the DNA strand that coded for the given mRNA sequence would be:
3' - TAC GAT ATG GAG GAA TAT GAC ACT 5'
To answer these questions, we need to understand the genetic code and how the codons in the mRNA sequence correspond to amino acids. The genetic code is a set of rules by which information in mRNA is translated into the amino acid sequence of a protein.
a) The first codon in the mRNA sequence is "AUG." This codon is technically known as the start codon. It codes for the amino acid methionine (Met).
b) The number of amino acid residues in a polypeptide chain is determined by the number of codons in the mRNA sequence after the start codon. In this case, the mRNA sequence after the start codon is "CUA UAC CUC CUU UAU CUG UGA." To determine the number of amino acids, we count the number of codons: "CUA," "UAC," "CUC," "CUU," "UAU," "CUG," and "UGA." There are 7 codons in total. Each codon corresponds to one amino acid, so there will be 7 amino acids in the polypeptide chain.
To calculate the number of tRNA molecules needed to translate the polypeptide chain, we need to consider that each amino acid is carried by a specific tRNA molecule. Since there are 7 amino acids, we will need 7 tRNA molecules.
c) To determine the DNA strand that coded for the given mRNA sequence, we need to use the rules of complementary base pairing in DNA. In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
We can start with the given mRNA sequence: 5' - AUG CUA UAC CUC CUU UAU CUG UGA - 3'
To get the DNA strand, we replace each RNA base with its complementary DNA base:
A (adenine) in mRNA becomes T (thymine) in DNA.
U (uracil) in mRNA becomes A (adenine) in DNA.
G (guanine) in mRNA becomes C (cytosine) in DNA.
C (cytosine) in mRNA becomes G (guanine) in DNA.
Applying these rules, the DNA sequence corresponding to the given mRNA sequence is:
3' - TAC GAT ATG GAG GAA ATA GAC ACT - 5'
So, the DNA sequence that coded for the given mRNA is 3' - TAC GAT ATG GAG GAA ATA GAC ACT - 5'.