Question

What is the amino acid sequence encoded by base sequence UCA UUU UCCC GGG AGU of mRNA segment?
A) Glycine-Serine-Phenylalanine-serine-Glycine.
B) Serine Phenylalanine-Serine-Glycine Serine.
C) Serine-Phenylalanine Glycine-Serine-Glycine.
D) Methionine-Phenylalanine Serine-Glycine Serine.

Answer 1

Hint: We know that the genetic code is unambiguous or specific because one codon codes only for one amino acid. Genetic code is degenerate because some amino acids are coded by more than one codon.

Complete answer:
As we know that the codon is a three nucleotides sequence of mRNA that specifies the addition of specific amino acids. The codon is present on the coding strand of mRNA. The anticodon is found on the tRNA and is the part that base pairs with the codon to bring the appropriate amino acid to the ribosome. The codon that codes for amino acids are triplets. In total there are codons and out of codons, codons code for amino acids, and the remaining three codons do not code for any of the amino acids so they are called step codons.

The list of twenty amino acids that codons code for are Phenylalanine (Phe), Leucine (Leu), Isoleucine (Ile), Methionine (Met), Serine (Ser), Valine (Val), Proline (Pro), Threonine (Thr), Alanine (Ala), Tyrosine (Tyr), Histidine (His), Glutamine (Gln), Glutamine (Gln), Lysine (Lys), Aspartic acid (Asp), Glutamic acid (Glu), Cysteine (Cys), Tryptophan (Trp), Arginine (Arg), Glycine (Gly).

Also, the set of rules used by living cells for the translation of information present within genetic material in the coded form into amino acids is called genetic code. Each codon is a triplet. One codon code for only one amino acid. The amino acids for the codons sequence. An mRNA with sequence AGU- UUU- UCC- GGG- UCG will code for a polypeptide with amino acid sequence serine-phenylalanine-serine- glycine- serine. This makes option B correct.

Therefore, the correct answer is option C.

Note: Remember that the codon is a set of three base pairs sequences that are present on an mRNA strand. It corresponds to the specific amino acid or acts as a stop signal during protein synthesis. The nucleotides are abbreviated as A, U, G, and C. The anticodon is the complementary base pair.