The gene encoding resistance to which antibiotic are considered useful selectable marker for E. coli.
(A) ampicillin
(B) tetracycline
(C) kanamycin
(D) penicillin
(E) chloramphenicol
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (B), (C) and (E) only
A selectable marker lets only the cells that have taken up the vector grow, so the transformants can be picked out.
(A) ampicillin — Correct. Named by NCERT.
(B) tetracycline — Correct. Named by NCERT; pBR322 carries resistance genes for both ampicillin and tetracycline.
(C) kanamycin — Correct. Named by NCERT.
(D) penicillin — Incorrect. NCERT does not list penicillin among the useful selectable markers for E. coli.
(E) chloramphenicol — Correct. Named by NCERT.
NCERT Extract:
Cloning Vectors – “… Transformation is a procedure through which a piece of DNA is introduced in a host bacterium (you will study the process in subsequent section). Normally, the genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin, etc., are considered useful selectable markers for E. coli.”