Quiz 3: Gene Expression in Prokaryotes and Eukaryotes PDF

UST / BIOL3321: Genetics My Grade: ____________ / 100 Formative Assessment My Time: ___________ min Quiz 3: Gene Expression in Prokaryotes and Eukaryotes...

UST / BIOL3321: Genetics My Grade: ____________ / 100 Formative Assessment My Time: ___________ min Quiz 3: Gene Expression in Prokaryotes and Eukaryotes True or False? (3 points each = 45) 1. ___F___ In eukaryotes, translation occurs cotranscriptionally. 2. ___F___ A trans-acting factor is any protein that can be synthesized from a mRNA. 3. The genetic code has one codon that acts as a start signal (AUG) and three codons that function as a stop signal (UAA, UAG, UGA). 4. ___T___ In prokaryotes, the 30SPIC contains the 30S ribosomal subunit, initiation factors 1-3 and the initiator tRNA. 5. ___T___ The great majority of eukaryotic genes are monocistronic. 6. ___T___ Prokaryotic genes are intronless. 7. ___T___ Eukaryotes have several different types of RNA Polymerases, including three nuclear types. Additional RNA polymerases are found in the mitochondrion and chloroplast. 8. ___F___ The promoter is an example of a trans-acting factor. 9. ___T___ Sigma and general transcription factors are examples of trans-acting factors. 10. ___T___ In eukaryotes, enhancers are an example of a cis-acting element. 11. ___T___ In eukaryotes, the following are examples of elements that make up the core promoter: TATA box, CAAT box, GC box. 12. ___F___ The RNA coding region of prokaryotes and eukaryotes are very similar. 13. ___F___ In eukaryotes, the PAS is the poly(A) polymerase. 14. ___T___ In eukaryotes, mRNA processing is achieved by 5’ capping, splicing, and 3’ end processing (3’ cleavage and polyadenylation). 15. ___T___ From a molecular perspective, the major difference between prokaryotic and eukaryotic translation can be seen during initiation, as the molecular process for elongation and termination of translation are very similar in both groups of organisms. Fill in the blank (4 points each = 39) 1. ___Consensus sequence__________: term that describes the sequence of most commonly found nucleotides at a specific site. 2. ___Cis-acting element___________: DNA sequence that has regulatory function and often acts as a binding site for one or more proteins to regulate gene expression. 3. ___Sigma domain 2____________: domain of the sigma factor that interacts with the non-template strand so that DNA can melt, and the single stranded template can enter the active site of the RNA polymerase. 4. ___Intrinsic transcription termination____: this type of transcription termination is observed in prokaryotes and is caused by the presence of a short, GC-rich palindromic sequence on the template strand, followed by a short stretch of adenines, that can fold to form a hairpin in the nascent mRNA, disrupting the RNAP. 5. ___Non-overlapping__________: characteristic of the genetic code that means that after the reading frame is set, each nucleotide only be included once in a codon. 1  6. ___Specific____________________: feature of the genetic code that means that each codon will only code for one single amino acid. 7. ___IF2________________________: in bacteria, this initiation factor is the one that brings the initiator tRNA to the P site on the small ribosomal subunit (30S). 8. ___Decoding, peptide bond formation, translocation_______________________: are the three steps of bacterial translation elongation. 9. ___EF-Tu_____________________: this bacterial elongation factor is in charge of bringing different tRNAs to the A site of a 50S ribosome to continue protein synthesis. 10. ___EF-G_________________________________________: this bacterial elongation factor is responsible for the translocation of the ribosome on the mRNA. 11. ____Enhancers, Silencers and Insulators_____________________: are three common types of distal promoters in eukaryotes. 12. _Cleavage and polyadenylation specific factor (CPSF)_: eukaryotic protein complex that binds RNAP II to allow termination of transcription after transcription of PAS. 13. _Exon skipping, alternative 5’ or 3’-splice sites, mutually exclusive exons, intron retention, alternative promoter, alternative polyadenylation site_: are the mechanisms that can lead to alternative splicing of a primary transcript. Draw 1. (8 pts) A prokaryotic gene. Label all segments. 2. (8 pts) An eukaryotic mRNA. Label all segments. 2