Origin Of Replication Is The Starting Point Of Dna Replication Essay

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BME-603 Exam 2 - Tao Xu (Nov-9-2016)

Origin of replication is the starting point of DNA replication. It cannot replicate in the host cells without this site.
Antibiotic resistance gene can be served as a select agent to find the right clone and then improve the plasmid transformation efficiency. Antibiotic resistance gene can also give the bacteria a pressure to have the plasmid, because the bacteria would use more energy to replicate both the plasmid and its own DNA.

(1) The protein needs complex eukaryotic post-translational modifications for structure.
(2) The eukaryotic proteins are not well folded in E. coli and form insoluble aggregates.
(3) Proteins are secreted, membrane or intracellular.

cDNA library is usually used to expressing eukaryotic gene in prokaryotes. There are no introns in E. coli DNA, so it does not have enzymes which could cut it out in the transcription procedure. In cDNA library, there are no introns, so it could be expressed in E. coli cells.
Genomic DNA library have the non-coding and regulatory sequence while cDNA library doesn’t, but genomic DNA library is hard to make and maintain.

(1) 2-10 kb fragments: Plasmid
Reason: Plasmid is autonomous and self-replicating circular extra-chromosomal DNA molecule. The plasmid-based vectors is usual used to clone small DNA inserts up to 15 kb.
(2) 15-20 kb fragments: Bacteriophage lambda
Reason: Bacteriophage λ is an E. coli virus. Insertion vector is usual used to clone inserts from 5–11 kb, while
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