AP BIOLOGY

Detailed explanation-1: -The ampicillin kills any cell that did not get transformed with the plasmid. This means that the only bacteria which can grow to form visible colonies on a plate containing LB nutrients and ampicillin are transformed cells.

Detailed explanation-2: -The bacterium cannot grow in the presence of the antibiotic ampicillin unless it contains the plasmid, and so there will be no growth on the LB/Amp plate of the bacteria without the plasmid.

Detailed explanation-3: -These plasmids are effectively holding their host bacterial cell hostage – if they are ever lost from the cell, they won’t be able to provide the antidote and the cell will die.

Detailed explanation-4: -Ampicillin is commonly used as a selection marker since it binds to and inhibits the action of several enzymes that are involved in the synthesis of the cell wall. The ampicillin-resistant gene (ampR), on the other hand, catalyzes the hydrolysis of the B-lactam ring of ampicillin and naturally detoxifies the drug.

Detailed explanation-5: -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.