After you take 50 ?1 of competent cells and transform these with 1 ng of uncut p
ID: 275184 • Letter: A
Question
After you take 50 ?1 of competent cells and transform these with 1 ng of uncut plasmid DNA, the transformation reaction is added to 950 ?1 of SOC medium. From that volume you make a 1:10 dilution in SOC medium and then plate 100 ul of this onto a LB + Amp plate. If 250 colonies, grow on the plate what is the transformation efficiency of the competent cells per ug DNA? Select one: a. 2.5 x 10' cfu per ?g b. 1.25 x 10 cfu per ug c. 2.5 x 10 cfu per ug d. 2.5x 10 cfu per ug O O How much 1.5 kb PCR product should be added to a ligation in which 25 ng of 3.5 kb vector will be used if a 3:1 insert to vector molar ratio is desired? Select one: a. 175 ng b. 32.14 ng Oc. 19.44 ng d. 3.57 ngExplanation / Answer
1)Transformation efficiency(TE) is calculated using the formula
TE=colonies on plate/ng plated
=250/1×103×10
=2.5×106 cfu per µg
2)amount of PCR product = kb of insert/kb of vector × ng of vector × final dilution
= 1.5/3.5×25×3/1
= 32 . 14ng