Question

Assignment: For each question, describe how you would make the solution using the stocks or reagents listed below. On our lab prep shelves, we have the following solutions and powders:

Sodium citrate (FW = 43.7 g/mol)

SDS powder (FW = 288.38 g/mol)

0.5 M EDTA IPTG powder (FW = 238.3 g/mol)

20 mg/mL X-gal solution

1000X ONPG

Premade LB

Premade LB agar

0.5 mM Colchicine

50X gel running buffer

Agarose powder

95% ethanol

100 mg/mL Ampicillin

10X BamHI restriction enzyme digestion buffer

milliQ water dimethylformamide (DMF)

Example 1. (DNA isolation lab) How would you make 100mL of 0.15M Sodium Citrate, 5% SDS, 0.001M EDTA solution (one solution that contains all of these reagents)? Answers 0.65 g Sodium citrate 5 g SDS 0.2 mL of 0.5 M EDTA Add 75 ml of water and mix well. Then add water up to 100 ml to complete.

Example 2. (B-gal) How would you make a 10 fold dilution of 20 mg/ml X-gal? X-gal is not soluble or stable in water, but it is in dimethylformamide. What would the concentration of the diluted solution be? Answer Add 1 ml of the stock solution to 9 ml of DMF. 2 mg/ml

Problem for you

1. How would you make 500 mL LB = 40ug/mL X-Gal? ( the LB is made, so you just need to figure out how much X-Gal to add)

How would you make 500mL LB = 0.1mM IPTG? You cannot add solid IPTG to media. Instead use a sterile 1M stock of IPTG

How would you make 500mL LB + 40ug/mL X-gal + 0.1mM IPTG?

Please show all work that got you to your solution

thank you!