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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. 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






2. The process of increasing the expression of inducible genes






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






4. In the presence of glucose and lactose - bacteria grows first on glucose - then growth levels off - and starts growing on lactose. You have diauxie growth because (1) CAP helps recruit RNAP. in the presence of glucose - CAMP is low so it can't bind t






5. Ribosome doesn't stop at trp codons and stem loop forms between 3 and 4. RNAP stops prematurely (attenuated)






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






7. Gene products increase in concentration under particular molecular circumstances






8. 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






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






10. The process of decreasing the expression of inducible genes






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






12. Expression levels rise and fall in response to molecular signals






13. 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.






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






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






16. Need to remove introns before changing into mRNA - then take mRNA out of the nucleus. Has 3 RNAP (RNAP I synthesizes rRNA - II synthesizes mRNA - III synthesizes tRNA and small rRNA). Transcription factors are similar to sigma factors.






17. 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.






18. 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.






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






21. A strand segment complementary to the template with a free 3'OH group






22. A reading frame without termination codon among 50 or more codons. Usually correspond to genes that encode proteins






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






24. 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.






25. 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






26. 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






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






28. The first two bases of the codon always form strong Watson -Crick base- pairing. The first base in the anticodon determines the number of codons a tRNA can recognize. The first position in anticodon is often modified to inosine to facilitate wobble b






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






30. A templated process just like in DNA replication and there is no processing steps.






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






32. 1. Ethidium bromide staining 2. P32 - P33 radioactivity 3. Fluorescence 4. Agarose gel electrophoresis






33. Unvarying expression of gene






34. 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






35. Nonsense mutation in gene that results in truncated protein can be lethal. Sometimes a second mutation arises that counteracts the effects of the mutation. Amber stop codon (UAG/TAG/etc) and amber suppressor tRNA (CUA/etc) can restore protein size an






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






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






38. Structural and functional units of life. All organisms are made of cells - all cells are derived from preexisting cells - the purpose of a microorganism is to make another microorganisms as quickly as possible; alter metabolism of microorganism to ma






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






40. 1. mRNA - template for protein synthesis 2. tRNA - carrier of amino acid (the adaptor)3. aminoacyl- tRNA synthetase - pairs tRNA with the cognate amino acid - needs ATP 4. ribosome - site of protein synthesis - read in three frames - start codon is A






41. 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






42. Multiple effects from a single gene






43. Eukaryotic. mRNA that codes for one protein






44. 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)






45. 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






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






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






48. 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






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






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