Bio253Sec1_Exam2_F21_1

Exam 2 Fall 2021 253L-01 Name:___________________________________________________ Date:____________________________________________________ Tuyen Ta 10/15/21

___/12 1. A general restriction digest recipe contains. SHOW ALL YOUR WORK FOR CREDIT: a. If the original DNA concentration was 2.25 μg/μL, how much DNA (in μL) should be added to the reaction to add 5.0 μg of DNA ? Show your work below. (3 pts) b. If the original BSA concentration was 30X (treat X as the unit for concentration), what will be the ending concentration of BSA in the reaction of 20 μL ? Show your work below. (3 pts) c. If the original NEB Buffer 1.1 concentration was 40X (treat X as the unit for concentration), what will be the ending concentration of buffer in the reaction of 20 μL ? Show your work below. (3 pts) d. How much ddH 2 O was added to the restriction digest if you used one restriction enzyme? (3 pts) 5.0 μg of DNA 3.0 μL of 40X NEB buffer 1.1 0.5 μL of 30X BSA 0.5 μL of restriction enzyme X μL ddH 2 O for a final volume of 20 μL 50mg / MI 2.25 µ g = 2.2Mt MI :3o × M2 : ? M2 :( 30 × 0.51/20 =o.7 ☒ V1 : 0.5Mt V2 : 20 µ L MI :4O ✗ M2 : MZ - (40 × 3)/20=16 × 1 V1 : 3Mt 2 : 20Mt 20-0.5-0.5-2.2 - 3 = 13.fm/ddHz0@

___/16 c. Assuming figure below is a gel electrophoresis, draw in the approximate location for the plasmid(s) digested above (2b), relative to the 1kb ladder? (16 pts). a. Lane 1 represents the 1kb ladder b. Lane 2 represents digested pPotter.xdna but this is a partial/incomplete digest. (Hint: your enzyme only had 75% activity in buffer 1.1) c. Lane 3 represents digested pLovegood.xdna d. Lane 4 is an undigested pPotter.xdna with supercoiled and linear plasmid e. Lane 5 is an undigested pLovegood.xdna with relaxed/circular plasmid only Linear circular circular 1500 900 825 550 400 112

Exam Total ___/50 ___/6 3. E. coli can be made competent in the laboratory by treatment with _____ ions (2 pts). a. K +1 b. Ca +2 c. Mg +2 d. Rb +1 e. None of the above are correct. E. coli cells can take up DNA from their environment without any added ions. 4. If your mystery plasmid was pLovegood (see question 2) and you successfully transformed your competent cells with this plasmid: draw in the circles provided below what the bacterial growth would look like on an LB agar plate (a) and an LB agar plate with ampicillin (b). Also describe what each plate would look like if you observed these plates under UV light (4 pts). a. LB agar only: Under UV light the plate would look like:_______________________________________ b. LB agar with ampicillin: Under UV light the plate would look like:_______________________________________ 0 ÷ p o no color ° < G o O , o - o . . : ooo 0 , ° o ° i purple dots