Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Bacteriophage Vectors
Bacteriophages are viruses that attack bacteria. Mainly phage lyses the bacterial cells they infect (lytic phages). But many others may choose to follow either lysogenic or a lytic cycle; in the second situation, the phage chromosome integrates into the bacterial chromosome and multiplies with the latter as prophage (temperate or lysogenic phages). The prophage can dissociate from the bacterial chromosome and follow the lytic cycle. Many bacteriophage are used as cloning vectors, the most generally used E. coli phages being λ (lambda) and M13 phages. Plasmid vectors have to be introduced into bacterial cells which are then cloned and choose for the recovery of recombinant vectors. In contrast, the phage vectors are sprightly tested to an suitable bacterial lawn (a constant bacterial-free zone in the bacterial lawn). Phage vectors show two advantages over plasmid vectors. (1) it is easier to screen a large number of phage plaques than bacterial colonies for the identification of recombinant vectors.(2) They are more efficient than plasmids for cloning of large DNA fragments; the largest cloned insert size in a λ vector is just over 24 kb, while that for plasmid vectors it is less than 15 kb λ Phage Vectors The λ genome (total 48,502 bp) contains an source of replication; genes for head and tail enzymes and proteins for DNA replication lysogeny and lysis; and single-stranded protruding cohesive ends of 12 bases (5' GGGCGGCGACCT; the other end is opposite to it; i.e.CCCGCCGCTGGA 5'). The λ genome remains linear in the phage head, but within E. coli cells the two cohesive ends anneal to make a circular molecule essential for replication. The sealed cohesive ends are known cos sites that are the sites of cleavage during and are essential for packaging of the mature phage DNA into phage heads. The λ DNA need to be larger than 38 kb and smaller than 52 kbto be packaged into phage particles. The genes for lysogeny are situated in the segment among 20 and 38 kb; the complete or a part of this segment is deleted to create λ vectors to (1) accommodate larger DNA inserts and (2) to ensure that the recombinant phage is always lytic.
ENERG Y TRANSFORMATION - During photosynthesis radiant energy is converted into chemical energy by green plants. In biluminiscent organisms .e.g glow worm, noctilluca &
The different organs of the respiratory system Nostrils through which we inhale air in the nasal cavity Pharynx Larynx Trachea (wind pipe) Lungs - Bronchi,
Q. How many chambers do the mammalian heart and the bird heart have? Concerning temperature maintenance what is the benefit of the double and complete circulation of these animals?
What is oxygen-haemoglobin dissociation curve? Explain the role of red blood cells in the transport of oxygen and carbon dioxide by blood. Briefly describe the principle, pr
Population Parameters and Regulation Population can be defined as a group of organisms of same species occupying a specific area at a particular time, such as all the deer or
what is the genetic code of life
Determine what is dermal branchiae? External extensions of outer epidermis and peritoneum of the echinoderm body cavity. Both outer epidermis and inner peritoneum are lined wit
What are the five kingdoms into which living beings are divided? Which group of living being is out of this classification? The five kingdoms of living beings are the kingdom M
Importance of fat synthesis and storage : As is clear from above account, all surplus nutrients, digested and absorbed from above the immediate need of body, are readily
What is the pH inside the stomach? Why is there a need to keep that pH level? How is it maintained? Which are the cells that produce that pH? The normal pH of the gastric juice
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd