Be sure to snawer all parts. Consider the ollowing mRNA seqences 5\'-CAG AGA CCA

Question

Be sure to snawer all parts. Consider the ollowing mRNA seqences 5'-CAG AGA CCA.3 What snino acid sequence is coded for by this mRNA? h. What is the amino acid sequence if s mntation converts CAC to CAA? e. What is the amine acid sequence if a mutation converts AGA to AUA What in the amino acid segaence if a mutaion converts CCA to CGA? e. What occurs if A is added to the bepinning of the chain? b. TABLE 22.3 The Genetic Code-Triplets in Messenger RNA Third Base Second Base UU Phe UCU Ser UAU Tyr UGU CysU ULIC Phe UCC Ser UIAC Tyr UGC Cys ULIA Lu ICA Ser IAA Stop UIGA StopA ULUG Lau UCG Ser UAG Stop UGG Tr CULeu CCU Pho CAUHis CGU Argu Ul CLIA Lc CCA Pro CAA Gle CGA Ar ALIC le ACC Thr AAC A AGC Se ALIA e ACA ThrAAA ys AGA Ar AUO Met ACG Thr AAG 1ys AGG A GUU Val GCU AlaGAU Asp GGUG

Explanation / Answer

Ans. #a. Given,          mRNA = 5’-CAGAGACGA-3’

            AA sequence = Gln-Arg-Arg

#b. CAG mutates to CAA

Mutated mRNA = 5’-CAAAGACGA-3’

AA sequence = Gln-Arg-Arg

Type of mutation: Silent mutation

# The point mutation that does not change amino acid sequence is called a Silent Mutation. Silent point mutation arise due to substitution of one base with another base AND the mutated codon codes the same amino acid as wild type. It does not affect the amino acid sequence of resultant proteins.

#c. AGA mutates to AUA

Mutated mRNA = 5’-CAGAUACGA-3’

AA sequence = Gln-Ile-Arg

# The point mutation that changes amino acid sequence is called a Missense Mutation (compared to original sequence).

#d. CGA mutates to GGA

Mutated mRNA = 5’-CAGAGAGGA-3’

AA sequence = Gln-Arg-Gly

# The point mutation that changes amino acid sequence is called a Missense Mutation (compared to original sequence).

#e. Mutated mRNA = 5’-ACAGAGACGA-3’

AA sequence = Thr-Glu-Thr

# Frameshift mutation is the insertion or deletion of on ‘n’ residues (here, insertion of A) in the reading frame of DNA, where n is NOT divisible by 3. It thus changes the reading frame of mRNA because the reading frame is shifted by a number not equal to 3 or its multiple – which is the basic unit (triplet codon) of translation.

Change in the reading frame leads to the largest extent of changes in the amino acid sequence depending on the position of mutation (closer is the mutation to 5’end of mRNA, greater would be change in amino acids sequence).

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.