Difference Between Cosmid and Phagemid

The key difference between Cosmid and Phagemid is on the type of sequences it contains. A Cosmid contains a cos site and a plasmid. Therefore, it is a hybrid vector while a Phagemid is a plasmid that contains an F1 origin of replication of the F1 phage.

1. What is phagemid vector?
2. What is a COS site?
3. What are cosmid vectors?
4. What happens once the cosmid enters the E coli cells?
5. Which plasmid vector is smaller in size?
6. What is M13 phage vector?
7. What is lambda phage DNA?
8. Is lambda DNA circular or linear?
9. What is meant by sticky ends?
10. What are plasmid vectors used for?
11. What is pBR322 used for?
12. What is the advantage of using polylinker in a vector?

What is phagemid vector?

A phagemid or phasmid is a DNA-based cloning vector, which has both bacteriophage and plasmid properties. These vectors carry, in addition to the origin of plasmid replication, an origin of replication derived from bacteriophage.

What is a COS site?

The cos site represents the junction between two genomes in a concatemer and serves as the packaging initiation site. Unlike the pac sequences of viruses that use the head-full packaging mechanism, cos also serves as a specific packaging termination sequence.

What are cosmid vectors?

Cosmid vectors are hybrids between plasmid and phage λ vectors. ... Cosmid vectors are designed to clone large fragments of DNA and to grow their DNA as a virus or as a plasmid. Cosmid vectors are used in homologous recombination between two different plasmids in the same cell and grown in both bacteria and animal cells.

What happens once the cosmid enters the E coli cells?

Explanation: Once cosmids are inside the E. coli cells, they don't generate more phage but are propagated as plasmids. It is so because no more coat protein genes are present and thus it can't be packaged. They can't give rise to plaques.

Which plasmid vector is smaller in size?

They are based on pUC18, by removing the lacZ fragment and all useless DNA between the active features. The plasmid pICOz is even smaller (only 1185 bp). It was constructed by replacing the ampicillin resistance gene in pUCmu by the zeocin resistance gene.

What is M13 phage vector?

M13 is a filamentous bacteriophage (inovirus) composed of circular single-stranded DNA (ssDNA) which is 6407 nucleotides long encapsidated in approximately 2700 copies of the major coat protein p8, and capped with about 5 copies each of four different minor coat proteins (p3 and p6 at one end and p7 and p9 at the other ...

What is lambda phage DNA?

Lambda DNA, a linear, double-stranded phage DNA containing 12 bp single-stranded complementary 5'-ends, is derived from an Escherichia coli bacteriophage (Bacteriophage lambda cI₈₅₇ Sam7). Lambda DNA can also be used as a substrate in restriction enzyme activity assays. ...

Is lambda DNA circular or linear?

Lambda is a medium size E.

The DNA molecule of 48502 basepairs is linear and except for the extreme ends double-stranded. At each end the 5' strand overhangs the 3' strand by 12 bases. The sequences of the ends are complementary.

What is meant by sticky ends?

After digestion of a DNA with certain Restriction enzymes, the ends left have one strand overhanging the other to form a short (typically 4 nt) single-stranded segment. This overhang will easily re-attach to other ends like it, and are thus known as "Sticky ends".

What are plasmid vectors used for?

Plasmid vectors are the vehicles used to drive recombinant DNA into a host cell and are a key component of molecular cloning; the procedure of constructing DNA molecules and introducing it into a host cell.

What is pBR322 used for?

pBR322 DNA is a commonly used plasmid cloning vector in E. coli (1). The molecule is a double-stranded circle 4,361* base pairs in length (2). pBR322 contains the genes for resistance to ampicillin and tetracycline, and can be amplified with chloramphenicol.

What is the advantage of using polylinker in a vector?

Plasmid vectors that contain a polylinker will be cut only once by multiple restriction enzymes, each acting at its own site. Inclusion of a polylinker in a plasmid vector thus permits cloning of restriction fragments generated by cleavage of DNA with multiple different restriction enzymes.