Ch. 13 HW.doc

Ch. 13 HW Instructor: Dr. Sanghamitra Mohanty MCQ: Which are the common consensus sequences involved in initiation of transcription? GGTTC, TTAT CAAT, TATA TTTAAA, GGGCCC Any trinucleotide repeat Satellite DNAs An intron is a section of Protein that is clipped out post-translationally RNA that is removed during processing of RNA DNA that is removed during DNA processing tRNA that binds to the anticodon carbohydrate that serves as a signal for RNA transport Polynucleotide phosphorylase is the key enzyme used for the manufacture of synthetic RNA for cell-free system ribosomal translocation peptide bond formation production of ribosomal proteins degradation of RNA What is the initiator codon in both pro- and eukaryotes? Which amino acid is recruited by this triplet? UAA, lysine UGA, arginine AUG, arginine AUG, methionine UAA, methionine Select three post-transcriptional modifications often seen in the maturation of mRNA in eukaryotes. 3?-capping, 5?-poly A tail addition, slicing 5?-capping, 3?-poly A tail addition, slicing 5?-poly A tail addition, excision of introns, capping Removal of exons, insertion of introns, capping Base modification, heteroduplex formation, capping When examining the genetic code, it is apparent that There can be more than one amino acid for a particular codon AUG is the stop codon There can be more than one codon for a particular amino acid The code is ambiguous in that the same codon can code for two or more amino acids There are 4 stop codons and two start codons The relationship between a gene and a messenger RNA is that genes are made from mRNAs mRNAs are made from genes mRNAs make proteins, which then code for genes all genes are made from mRNAs mRNA is transcribed to DNA True or False: mRNA is usually polycistronic in eukaryotes. T/ F hnRNA is a primary transcript in eukaryotes that is processed prior to involvement in translation. T/ F Transcription factors function to help move ribosomes along the mRNA. T/ F RNA processing occurs when amino acids are removed from nascent proteins. T/ F An intron is a section of an RNA that gets spliced out. T/ F Short Questions: Draw and label a typical bacterial promoter. Include any common consensus sequences. How are promoters and enhancers similar and how they are different? What protein associated with a transcription factor is common to all eukaryotic promoters? What is its function in transcription? Compare and contrast replication and transcription. How they are similar and how are they different? Describe the structure of RNA polymerase in bacteria. What is the core enzyme and what is the role of sigma factor? Problems: What would be the most likely effect of a mutation at the following locations in an E.coli gene? ? 9, B) - 35, C) - 20, D) Start site The following diagram represents a transcription unit on a DNA molecule. SHAPE \* MERGEFORMAT Assume that this is a bacterial DNA. Draw the approximate location of the promoter and terminator for this transcription unit. Assume that this is a eukaryotic DNA. Draw the approximate location of the promoters of RNA polymerase II. A strain of bacteria possesses a temperature-sensitive mutation in the gene that encodes the rho subunit. At high temperature, rho is not functional. When these bacteria are raised at elevated temperatures, which of the following effects would you expect to see? Transcription does not take place All RNA molecules are shorter than normal All RNA molecules are longer than normal Some RNA molecules are longer than normal RNA is copied from both DNA strand Explain your reasoning for accepting or rejecting each of these five options.