Translation of mRNA to produce proteins is highly regulated.  For example, one factor that regulates eukaryotic translation is the polyadenylate binding protein (PABP).  PABP upregulates translation by binding the poly-A tail of an mRNA molecule (ie, the 3' end of mRNA consisting of multiple adenosine residues) to help recruit the ribosome.PABP consists of a single polypeptide chain and contains four distinct RNA recognition motifs (RRM's), each of which contains four β-strands and two α-helices.  Mutation experiments revealed that each RRM binds poly-A tails through residues in several β-strands.  Crystallography showed that the two α-helices in each RRM, which consist of amino acids 9-24 and 52-60, respectively, help hold the β-strands in the correct orientation for RNA binding.In addition to binding poly-A tails, PABP can also bind to the eukaryotic initiation factor eIF4G through the α-helices in the RRM regions.  When both eIF4G and mRNA with a poly-A tail are present with PABP, a ternary complex between the three molecules can form.  This complex further enhances translation relative to the PABP-mRNA complex alone.  To better characterize these binding interactions, PABP was electrophoresed in a native gel in the presence of mRNA containing a poly-A tail.  When eIF4G was added, PABP affinity for poly-A tails increased 10-fold.  Additional observations revealed that the affinity of PABP for eIF4G increased 12-fold when mRNA with a poly-A tail was added. Question 55Each of the following amino acid residues is likely to be found in the portion of the RRM that binds eIF4G EXCEPT:A.LeucineB.ArginineC.GlycineD.Serine

How is translation initiated?Group of answer choicesTwo ribosomal subunits bind to the mRNA transcript.DNA helicase binds to the origins of replication.RNA polymerase binds to the promoter sequence.Two ribosomal subunits bind to the DNA sequence.

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on:Select one alternative:amino acids being attached to tRNA molecules that contain the correct codon.the anticodon binding to the corresponding codon.small ribosomal subunits binding to specific large ribosomal subunits.ribosomes binding to specific mRNA molecules.

Which of the following statements about translation are true.0 / 1 pointPost-translational modifications is the binding of repressor proteins to a sequence found on an mRNA molecule.A ribosome has two subunits. The large subunit finds the mRNA to begin translation, while the small subunit has two sites for amino acids to bind.Translation is performed by ribosomes in both prokaryotes and eukaryotes.Transfer RNA (tRNA) are used to bring the next amino acid to add to the polypeptide chain by matching to the next codon in the mRNA being translated. After the amino acid is added, the tRNA can then be repurposed for a different amino acid and codon pairing.IncorrectThis is incorrect. The small subunit finds the mRNA to begin translation, while the large subunit has two sites for amino acids to bind. The A site accepts transfer RNA (tRNA) bearing an amino acid, while the P site binds the tRNA to the growing chain.

On an mRNA, the triplet grouping of ribonucleotides used by the translation machinery during polypeptide synthesis.Group of answer choicesTATA boxintronexonreading framecodonprimary transcript

During the process of translation, the growing polypeptide chain is released from the ribosome when:Select one:a. The 7-methylguanosine cap is reachedb. A chain terminating tRNA binds to the ribosomec. The poly A tail is reachedd. A chain terminating codon is reached