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Molecular Biotechnology

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
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  • Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. AARS charges the correct amino acid to tRNA in a two- step reaction.






2. 1. Synthesis of commercial products by recombinant organisms 2. Biopolymers 3. Bioremediation 4. Biomass utilization






3. Operator site - araC binds to this site and represses its own transcription from the PC promoter. In the presence of arabinose - araC bound at this site helps to activate expression of Pbad promoter






4. A segment of DNA molecule contains the information required for synthesis of a functional biological product






5. The repressor dimer (aporepressor) can't bind to the repressor. Transcription from the promoter is not stopped. When tryptophan is bound to the repressor dimer - the repressor changes configuration so that it can bind to the operator and transcriptio






6. Inducer site; araC bound at this site can simultaneously bind to the araO2 site to repress transcription from the Pbad promoter. In the presence of arabinose - araC bound at this site helps to activate expression of Pbad promoter.






7. Codes for three enzymes needed to catalyze the metabolism of arabinose. The operon is regulated by araC gene product.






8. A cell that contains a nucleus and membrane bound organelles






9. When arabinose is absent - there is no need to express the structural genes. AraC does this by binding simultaneously to araI and araO2 - making a looped DNA. This blocks access to Pbad promoter. AraC is an autoregulator of its own expression and the






10. Release DNA - rewind DNA - release RNA; stop signals or rho mediated termination (hairpin is a palindromic GC- rich region followed by an AT- rich region; Rho is a termination factor that binds to nascent RNA) RNAP has sigma factor that recognizes pr






11. Eukaryotic. mRNA that codes for one protein






12. Unvarying expression of gene






13. Search for site to start transcription - unwind DNA; -35 region and pribnow region (-10 region).






14. Replication > DNA > Transcription > RNA > Translation > Protein






15. 1. LacI- makes an internal inducer -- NO. Found that lacI- doesn't dominate over lacI+ and is not always constitutive. 2. LacI- is a repressor protein -- YES. LacI+ dominates over lacI- because when both are together - lac operon is inducible. LacI m






16. Operons transcribed as single mRNA and mRNA codes for more than one protein.






17. Gene products decrease in concentration under particular molecular circumstances






18. 1. Initiation: unwind DNA at the origin of replication (ori) - bidirectional replications; regulated as required for cell division 2. Elongation: requires RNA primer to replicate 3. Termination: signaled by Ter sequence






19. TrpE through trpA are five enzymes that catalyze the synthesis of the amino acid tryptophan from chorismic acid. If the cell has enough tryptophan - then it doesn't need to waste energy transcribing this mRNA. In the presence of tryptophan - the oper






20. The process of increasing the expression of inducible genes






21. Start codon is usually ATG - first amino acid is n - formyl- methionine. It is assisted by initiation factors (IF) and requires ribosomal binding sites (RBS). It is a polycistronic protein translation (operon).






22. Select correct ribonucleotides; loss of sigma factor - transcription bubble - no need for primers






23. A unicellular organism that lacks a nucleus and membrane bound organelles






24. Attenuation






25. 1. Capping: 5' phosphate capped by 7- methyl guanosine and is a 5'-5' linkage instead of 5'-3' This makes RNA more stable 2. Intron removal 3. Export to cytoplasm 4. Polyadenylated mRNA precursor






26. 4. Cells + organelle 3. Supermolecular complexes 2. Macromolecules 1. Monomeric units






27. Polymerase binds to lac promoter weakly by itself and results in low levels of transcription even in the absence of lacI. The activator recruits the polymerase to the promoter region and increases its affinity for the promoter






28. 1. Nucleic acid hybridization: (a) bind single stranded DNA to a membrane support - (b) add single stranded labeled DNA (probe) under appropriate conditions - (c) wash the support to remove excess unbound labeled probe DNA - (d) detect the hybrid seq






29. Three sites recruit tRNA and forms peptidyl- tRNA bonds (E - exit; P - peptide; A - acceptor).






30. Determines amino acid selection. A noncognate amino acid charge incorrectly to the tRNA will be inserted into the protein. Introduce new amino acid by using tRNA for UAG.






31. Comprised of >50 proteins associated with rRNA units. Site of protein synthesis and binds mRNA and finds protein synthesis initiation sites. It also binds aa- tRNA and catalyzes peptide bond formation.






32. Chromosome (contains host genetic information) - plasmids (prokaryotes; small - self- replicating DNA; supercoil) - free nucleotides






33. A small catabolite molecule. Its level is determined by the level of glucose in the cell where glucose controls the rate of cAMP formation with ATP. When there is high glucose - there is low levels of cAMP. cAMP activator protein (CAP) has to bind cA






34. The process in which an exact copy of the double strand DNA is made. It is a templated process and occurs from 5' to 3' end. DNAP - RNA primer; semiconservative (each strand is a template for the replication of the complementary strand)






35. Important to suppress mutations at 3rd position and you don't need to have a lot of stop codons; cells can be more flexible






36. When half DNA strand has been denatured. Determined by GC content (triple bond)






37. When arabinose is present - it binds to araC and allosterically induces it to bind to araI instead araO2. If glucose is absent - then the presence of CAP bound to its site between araO1 and araI helps break the DNA loop and helps araC bind to araI






38. Binds to CAP binding site. In conjunction with araC bound with arabinose - it assists RNAP in binding to the Pbad promoter






39. Functions: enzymes - regulation - structural - cellular functions Polymers of amino acids and connected by peptide bonds. Can fold into complex structures.






40. C - N - O - H make up 99% cell weight - 70% is water






41. In E. coli - DNAP III can unwind DNA (helicase) and replicate both strands of DNA. It also has proofreading activity and corrects mistakes 3' to 5' exonuclease






42. The process of decreasing the expression of inducible genes






43. The small ribosomal subunit binds to 5'-G cap on processed mRNA (no RBS) - uses met instead of fmet for initiation; monocistronic translation






44. The ribosome translating the leader peptide arrives at the two tryptophan codons and has to wait for tryptophan. During this time - RNAP continues to transcribe. Stem loop between 2 and 3.






45. Operator site; araC bound at this site can simultaneously bind to the araI site to repress transcription from Pbad promoter






46. EF-Tu GTP binds with an aminoacyl- tRNA and brings it to the ribosome. Once the correct aminoacyl- tRNA is positioned in the ribosome - GTP is hydrolyzed and EF-Tu* GDP dissociates away from the ribosome






47. 1. mRNA: encodes genetic information 2. tRNA: transfer RNA - involved in protein synthesis (DNA to amino acids) 3. rRNA: ribosome RNA - involved in protein synthesis (polypeptide formation) 4. Ribozymes and RNAi - Can store genetic information and ca






48. Production of commercial products generated by the metabolic actions of microorganisms.






49. In prokaryotes - related genes often arrayed in tandem. A unit of bacterial gene expression and regulation - recognized by a regulator gene product






50. Gene products increase in concentration under particular molecular circumstances