Direct uptake of free DNA by bacterial cell is

Ans. c (Transformation) (Ref. Anantanarayan, Microbiology, 6th ed., 53; Ref. Q. 101 of MH-2005)Method of transmissionCommentTransformation# A phenomenon in which transfer of genetic information occurs through the agency of free DNA.# Certain cell lines, such as cancer cells, are also able to grow indefinitely in culture by this mechanism.Transduction# Transfer of a portion of DNA from one bacteria to another by bacteriophage.# It is not confined to transfer of chromosomal DNA; it transduces episomes and plasmids also.# Bacteriophages are viruses that parasitise bacteria and consist of nucleic acid core and a protein coat.# It is excellent tool for genetic mapping of bacteria.Lysogenic conversion# Phage DNA becomes integrated with bacterial chromosome as prophage, which multiplies synchronously with host DNA and is transferred to daughter cells; this is lysogeny and bacteria harbouring prophages are lysogenic bacteria.# In transduction, phage acts only as vehicle carrying bacterial genes from one cell to another, but in lysogenic conversion, phage DNA itself is new genetic element.Conjugation# The process whereby 'male' or 'donor' bacteria mates or makes physical contact with female or recipient bacteria and transfers genetic element into it.Sexduction# Process of transfer of host genes through f factor, resembles transductionTransfection# Transfer of a gene into a cell, enabling the transfected cell to form a new gene product.