Cloning Vectors MCQs Quiz and Flashcards

Study Notes

Plasmids as Cloning Vectors

A plasmid consists of an origin of replication, which allows for the replication of DNA fragments in the host cell.
Plasmids also contain an antibiotic resistance gene, which acts as a selectable marker to identify transformed cells.

Features of Cloning Vectors

A cloning vector requires an origin of replication (ori) for DNA replication and maintenance.
A selectable marker is necessary to identify transformed cells, such as antibiotic resistance genes (e.g., ampicillin, chloramphenicol, tetracycline, or kanamycin).
A cloning site is required for the insertion of foreign DNA.

Cloning Process

The antibiotic resistance gene is replaced with the desired gene at the cloning site, resulting in the loss of antibiotic resistance.
Recombinants can be selected from non-recombinants based on the loss of antibiotic resistance.

Plant Cell Transformation

The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens is modified into a cloning vector for plant cells.
The desired gene is introduced along with other required genes into the T-DNA, resulting in plant cell transformation.
The Ti plasmid contains genes for growth regulators, cytokinin and auxin, and energy sources for opine catabolism.

Animal Cell Transformation

Retroviruses have been modified to act as vectors for animal cells.

Competent Host Cells

Bacterial cells must be made competent to take up DNA, which can be achieved through treatment with divalent ions (e.g., calcium ions) and heat shock.
Competent cells can be used for DNA insertion through microinjection, biolistics, gene gun, or other methods.

Insertional Inactivation

Insertional inactivation is a method used to identify transformed cells by inserting a gene into the coding sequence of an enzyme, β-galactosidase.
The resulting inactivation of the enzyme prevents the formation of lactose, allowing for the identification of recombinant colonies.

Vectors for Plant Cloning

Agrobacterium tumefaciens is used as a vector for plant cells, carrying the T-DNA that results in plant cell transformation.

Description

Test your knowledge on plasmids, cloning vectors, and the essential features required for a cloning vector, like the origin of replication and selectable markers. Explore the role of plasmids in molecular biology techniques such as gene cloning and genetic engineering.