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Molecular Biotechnology 2

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. The number of cycles required for the fluorescent signal to pass the threshold (background level). This is inversely proportional to the amount of target nucleic acid.






2. Primers anneal to complementary sequences on DNA template and determine the boundaries of the amplified product.






3. A technique that sequences the N terminus and C terminus sequence of purified proteins. These sequences can be used to design degenerate primers and probe a gene library. (1) Purify protein from cell sample - (2) break it up - (3) enzyme assay - (4)






4. The host's immune system that protects against foreign DNA (DNA binding proteins). It protects the hosts DNA through methylation and digests DNA that isn't methylated. Hydrolyze phosophodiester bond at specific sequences. Binding/cutting sites can be






5. Genes that are put into a new host so that the new host can gain new/correct function






6. The first reverse transcriptase specifically purified for use in first stand cDNA reactions






7. Used so the cell isn't killed and can still transfer foreign DNA into a host cell. The DNA can be propagated in a host cell and hosts with the vector can be selected over hosts that don't have the vector. Plasmids - viruses - plasmids + viruses (cosm






8. Strong positive reactions with abundant nucleic acid






9. E. coli polymerase denatures at 95C and new enzyme has to be added each time. TaqP is a thermal stable organism and only need to add once - but will denature after 30 min at 95C (may be able to reduce temperature after a few cycles; increase denatura






10. SDS lysis cells - potassium acetate/acetic acid is used to neutralize pH and precipitates lipids and large proteins - centrifuge to separate out plasmid DNA from precipitates






11. Has been cloned and re- engineered to have negligible levels of RNase H activity - without compromising its first strand cDNA polymerizing function






12. DNA sequencing - Understand biological processes - Study the function of encoded protein - Introduce a mutation into the gene - Evolve a protein towards desirable functions - Obtain large amounts of a protein






13. Assist recombination between homologous DNA sequences.






14. Used to remove selection marker after Red- mediated recombination.






15. Directional cloning of a DNA fragment - single site cloning - blunt end cloning - polylinker - creating new restriction sites






16. 1. If a product is formed: PCR can be unsuccessful if the quality of DNA is poor - one of the primers doesn't fit - too much starting template (non - specific binding) - optimization 2. Product is of the right size: primers may bind to different part






17. 1. Decide the desired coverage of the genome 2. Choose an appropriate vector for making the library 3. Digest the genome pieces and clone into the vector 4. Introduce the library into e.coli host using appropriate means 5. Design probes to investiga






18. An identical copy. This term was originally applied to individual cells that were isolated and allowed to grow to create the same cell.






19. A DNA Virus that infects bacteria with its chromosomal DNA. The Phage DNA is linear (35-50 kb) but circularizes in host. It encodes virus specific enzymes and is replicated in the host. It gets integrated into bacteria genome.






20. Strong positive reaction with moderate nucleic acid






21. Four Components: 1. Template (Target DNA) - doesn't need to be purified and can be from anything 2. Primers (short oligonucleotides) 3. dNTP (building blocks) 4. Thermostable polymerase - no need for RNA primers like in actual DNA replication






22. (1) Gene is separated from chromosome - (2) gene is put into a vector - (3) vector replicates to produce multiple copies of the gene.






23. 1. Cycles of temperatures 2. 94C denatures DNA 3. Lower temperature so primers can bind to DNA at specific locations 4. Polymerase carries out templated DNA synthesis with primers at an optimal temperature (~72C) 5. Product serves as the template for






24. From bacteriophage lambda and help in the removal of chromosomal genes in e.coli. As little as 30 nt homologous region is required - which can be introduced as overhangs in a PCR reaction using the selection marker as template 1. Gam - protects line






25. 1. Label one end of DNA with radioactivity 2. Cut DNA at different places wherever A/G/C/T pop up using different chemicals 3. Line up DNA pieces by size using gel electrophoresis.






26. Fluorescent dye is attached to 3' of each of the four bases (ddNTP) and will emit a narrow spectrum of light when struck by an argon ion laser beam. All four ddNTP can be added to the same reaction. >800 bases can be sequenced






27. ATP sulfurylase quantitatively converts PPi to ATP in the presence of APS. This ATP drives the luciferase mediated conversion of luciferin to oxyluciferin that generates visible light in amounts that are porportional to the amount of ATP and is detec






28. Plasmids have an ori sequence for replication. The sequence of ori and plasmid encoded proteins determine the 'copy- number' of plasmids. Stringent control of replication (1 copy per cell division - low cell copy number plasmid); relaxed control of r






29. Use polyT to 'trap' the mRNA and leave tRNA and rRNA behind.






30. A DNA which is complementary to an RNA (a complementary DNA); Generally made by reverse transcription of mRNA. (1) purification of mRNA with polyT because mRNA has lots of polyA on 3' end - (2) first strand DNA synthesis using RTase - (3) second stra






31. 20-25 nt oligonucleotide that will hybridize to DNA of interest. It can be radiolabeled with kinase and 32P-ATP or fluorescently labeled.






32. Weak reactions with minimal nucleic acid (representing an infection state or environmental contamination).






33. 3' to 5' exonuclease - more expensive - yields less product - but has less error than TaqP






34. dNTP is added to the reaction Each time dNTP is incorporated to DNA - pyrophosphate (PPi) is released in a quantity equimolar to the amount of incorporated nucleotide.






35. Extrachromosomal - circular DNA that has autonomous - self- replicating genetic elements. Found in bacteria - yeast. Transferred to daughter cells during cell division. Size varies from 1kb ~ 200 -000 kb.






36. Restriction nucleases - electrophoresis - vector - ligase - bacterial host - identifying the cloned gene






37. Integrate into cellular chromosome.






38. 4-8 bp long (usually 6). Mostly palindromic because the nuclease is 2 enzymes coming together. There are 3 types of cleavage: (1) blunt ends - (2) 5' overhang sticky end - (3) 3' overhang sticky end.






39. Need: polymerase - dNTP (one is labeled with 32P to provide signal) - ddNTP (3'H will terminate DNA synthesis; dideoxyribose; only one is put in and added in excess) - synthesizes DNA and can deduce sequence wherever DNA stops synthesizing because o






40. Apyrase - a nucleotide degrading enzyme continuously degrades unincorporated dNTPs and excess ATP. When degradation is complete - another dNTP is added.






41. Can be used to linearize circular DNA - can have double digest - usually done at 37C but some done at 55C - digest time depends on the amount of enzyme






42. Small size (between 3-50 kb) and it is more efficient to transfer into host cell. Unique restriction enzyme sites and selectable marker (antibiotic resistance genes)






43. Introduced on plasmids sensitive to temperature






44. 1. Primer length is between 18-24 nucleotides long. 2. Duplex stability: both primers need to have similar Tm to have the same hybridization kinetics during the template annealing phase. Remove bases to have the same Tm 3. Non - complementary primer






45. During meiosis - homologous recombination happens in chromosomes to generate offspring diversity. Recombination is used to repair DNA damage and can be induced by a wide array of environmental stresses.






46. 1. Use RTase to go from RNA to DNA 2. Use RNAseH to get rid of RNA 3. Use TaqP to make top strand of DNA - can't detect quantity of RNA/DNA






47. Type I and III: cut and modify DNA by methylation - binding and cutting sites differ - requires ATP to move along DNA - and not efficient for DNA manipulation Type II: has only restriction activity - no modification; cutting sites are adjacent or wit






48. As the process continues - the complementary DNA strand is built up and the nucleotide sequence is determined from the signal peaks in the pyrogram.






49. 1. Detecting pathogens using genome- specific primer pairs 2. Screening specific genes for unknown mutations 3. Genotyping using known STS (sequence tagged sites) markers






50. May get a smear - can't tell the difference between bp - and limited by # of sequence it can generate because primers may only be able to do 1000 bp