Math Problems You have a stock solution of TAE at 50x concentration. In order to
ID: 214539 • Letter: M
Question
Math Problems You have a stock solution of TAE at 50x concentration. In order to make an agarose gel, you need your TAE at 1X. Tell me how much water and how much TAE you need. (1 point) 1. After diluting your TAE, you need to make a 1.5% gel. How much Agarose do you add to 50mL of 1X TAE? (1 point) 2. You are designing primers to test for the presence of an endotoxin in E. coli. The sequence below is your primer Calculate the Tm of the sequence. (1 point) (5') AGTCGTAGTCGATAGCGATGGCG (3) 3. 4. You have isolated the toxin and want to perform a cytotoxicity assay (experiment/test). There is an unlimited amount of toxin at a concentration of 500mg/mL. You need concentrations of 50 g/L and 5 g/L. Calculate the dilution for all of these. (tell me how many mL, ul, etc. you need to dilute to get the desired concentrations) 2 points) 5. You need to do a Restriction digest of the gene responsible for the endotoxin. Your digest buffer is at 10x concentration, and needs to be diluted to 1X. The total reaction volume is 20 ul. How much buffer should you add? (1 point)Explanation / Answer
1. Using the formulae, V1 * S1 = V2 * S2 we can easily calculate where V1 is the initial volume and S1 is the initial stock conc. V2 is final volume and S2 is final concentratiom.
so , 50 * x = 1 * 50 ( suppose our final volume is 50 ml)
So from this we get , 1 ml of TAE is required and 49 ml of water.
2. 1.5 percent gel means 1.5 g in 100 ml
so for 50 ml we need 0.75 g of agarose.
3. using the formulae
Tm = 4 * (G+C) + 2 *( A+T)
= 4 ( 13) + 2 (10)
= 52+20
= 72
4. 50 g/L = 50000mg /1000ml and suppose we make 1 lit volume
so, 500mg /ml * x = 50mg/ml * 1000ml
X = 50/500 * 1000
X = 1/10 * 1000 ml = 100ml
So basically it is a 1/10th fold dilution .
to make 1 litre of 50g/l ,we need 100 ml of 500 mg/ml + 900 ml of water.
similiarly for 1 litre of 5 g /l , which is a 100 fold dilution, we need 10 ml of 500mg/ml + 990 ml of water.
5. using ,V1 *S1 = V2 *S2
10 * X = 20 * 1
X = 20/10 = 2
So 2 ml of buffer should be added to 18 ml of water ( total = 20)