Question

846. What would happen to the amount of protein made per mRNA molecule is the enzyme Poly A Polymerase is defective? Why?

847. What would happen to the rate of TRANSCRIPTION if there was a frame shift mutation in the transcription unit? Why?

848. What would happen to TRANSLATION if there was a mutation such that a UGA codon was changed to UCA? Why?

849. What would happen to TRANSLATION if there was a nonsense mutation in the 5’ untranslated region of an mRNA? Why?

Answer 1

846.Poly A polymerase is involved in polyadenylation of the mRNA transcript so that it is transported to the cytoplasm to carry out the synthesis of protein.This step called tailing prevents the mRNA degradation and stabilizes it during protein synthesis.A defective poly A polymerase will therefore reduces the stability of the mRNA resulting in decreased amount of protein.

847.The transcription rate refers to the rate at which mRNA is produced and formation of mature mRNAand a frameshift mutation where either addition or deletion of a base occurs thereby shifting the reading frame.This results in a different mRNA and the maturation is altered which affects the rate inversely.

848.UGA is a stop codon, meaning that this codon signals to stop the translation process as it codes for no amino acids.When mutation changes UGA to UCA then , UCA codes for serine and the translation process will not stop and will result in the addition of serine in the chain.

849.Mutation in the untranslated region disrupts the integrity of the mRNA trancript and can result in the alteration of expression of genes.