AP BIOLOGY

Detailed explanation-1: -Bacteria without the plasmid are less likely to survive and reproduce. Some plasmids take extreme measures to ensure that they are retained within bacteria. For example, some carry a gene that makes a long-lived poison and a second gene that makes a short-lived antidote.

Detailed explanation-2: -The answer is that bacterial cells can exist without plasmid DNA. The term “plasmid” refers to the extrachromosomal genetic component of the bacterial cell that is distinct from chromosomal DNA. These are little double-stranded, circular DNA molecules with the ability to replicate on their own.

Detailed explanation-3: -Plasmids used in cloning contain an antibiotic resistance gene. Thus, all of the bacteria are placed on an antibiotic plate to select for ones that took up a plasmid. Bacteria without a plasmid die.

Detailed explanation-4: -E. coli is the most common bacterial species used in the transformation step of a cloning workflow. Since the natural competency of E. coli is very low or even nonexistent, the cells need to be made competent for transformation by heat shock or by electroporation.