DH5a

Question 1

F-

Answer 1

Doesn’t carry F plasmid

Question 2

Φ80lacZΔM15

Answer 2

Lambdoid prophage 80 carries delta lacZ M15 a defective version of the lacZ gene that upon expression results in a beta-galactoside missing amino acids 11-41 at the amino terminal end. alpha complementation can reinstate enzymatic activity of beta-galactoside and its basis of the blue/white selection

Question 3

Δ(lacZYA-argF)U169

Answer 3

Deletion of DNA from lacZ through argF allele. Renders cell unable to use lactose as a
sole carbon source (and also affects arginine biosynthesis).

Question 4

recA1

Answer 4

For reduced occurrence of unwanted recombination in cloned DNA; cells UV sensitive,
deficient in DNA repair; particularly desirable when cloning genes with direct repeats”!

Question 5

endA1

Answer 5

Elimination of gene coding for endonuclease I (non-specific digestion of DNA), results in improved (quality & yield) plasmid preps

Question 6

hsdR17(rK–, mK+)

Answer 6

Inactivation of EcoKI endonuclease (restriction but not methylation) allows transformation of unmethylated DNA (PCR)

Question 7

phoA

Answer 7

Mutation in alkaline phosphatase used for PhoA-based reporter system

Question 8

supE44

Answer 8

tRNA glutamine suppressor of amber (UAG)

Question 9

λ–

Answer 9

lambda lysogen deletion

Question 10

thi-1

Answer 10

Thiamine auxotroph: Requires thiamine for growth on minimal media.

Question 11

gyrA96

Answer 11

DNA gyrase mutant resistant to nalidixic acid

Question 12

relA1

Answer 12

Eliminates stringent factor resulting in relaxed phenotype. Allows RNA synthesis in absence of protein synthesis. relA locus regulates the coupling between transcription and translation.

Question 13

deoR

Answer 13

Regulatory gene that allows constitutive expression of deoxyribose synthesis genes; permits uptake of large plasmids but since DH10B a derivative of DH5a has shown to be deoR+ this genotype assignment is questionable.