Question

can someone explain throughly on how to find a-c??? thanks!!!

The following question will provide practice in interpreting and analyzing gel results. 5. You obtained the DNA electrophoresis gel below. Three samples of lambda phage DNA were digested with 3 different restriction enzymes and the digested DNA was applied to the gel in lane 4 and the bands were visualized. The Hind Ill digest was used as a molecular weight standard marker and produced 6 DNA fragments of known size: 23130 9410 6680 4360 2320 2030 base pairs Using graph paper, calculate/deduce the following: a. The sizes of the DNA fragments produced by enzyme "A b, which of the enzymes shown below was used in lane #2 of the gel (described as the unknown enzyme): Fragment sizes produced by Bam H1 Fragment sizes produced by EcoR1 Fragment size produced by Alw44 16841 7233 6770 6527 5626 5505 21226 7421 5804 5643 4878 3530 16179 13043 8286 5619 3375 2001 Unknown Enzyme: 4.1 60 .3 9.6 Hind III 31 11 88 0.2 nknown 13 1 3 11.6 Draw bands on the gel (in lane X) where you would expect the fragments generated by digesting the circular plasmid (to the right) with restriction enzyme X (the cut sites are shown in parentheses and the total length of the plasmid is 20,000 b.p. long) c. X (120) X a8012) Note: these bands are hypothetical ones and do not represent the true banding pattern of DNA cut with the given restriction enzymes.] 3200) X <12423) X 4531

Answer 1

For question A you should draw a graph using graph paper and draw the distance of each band (the numbers next to the band in the gel) in the X-axis and the size in base pares of the known fragments of Hind III in the Y-axis. Remember that smaller fragments run faster and they will be the ones at the bottom of the gel. To find the size of the bands produced by enzyme A you should use the graph. You first locate the mm in the X-axis and find the Y value corresponding to the band size.

b) If you look at the gel you can see that the smallest band on line 2 (the unknown enzyme) is located bellow the smallest band produced by the restriction enzyme Hind III which measures 2030 base pairs. This means that at least one fragment produced by the unknown enzyme should be smaller than 2030 bp. So the unknown enzyme is Alw44, whose smallest fragment size is 2002 bp.

Unoun Pb 23130 19/ 2313) be 2.3 2.S 940 39 с 40 bp Gb 6680 bp 360I 4360 be 2320 2030 2320 bp 14 25 4 3.i 9396 2.S 1.q x, band Sze ot the chzyme A ot2.smm

c) Each cut site is located at a random position numbered from point 0 (equals to point 20000 bp, the plasmid length). Between two cut sites, there will be a number of base pairs (corresponding to the fragment size) which is equal to the difference in the positions of the two cut sites (see image below). To draw the bands in the gel you need to use the same graphics drawn in answer A an find the X value with the fragment size calculated in the answer C (the Y value) and find the mm values of each band and draw it in the gel.

120 nagment. ,fies endured by en24nex are: 2086 3080 bp 3200-120) aoeo bp (4831-32 ): 1331 bp 80320. 320p bo 1331 bp 4531 18 082-12423) S609 bp 20000-180324 10 ) ニ 2000 bp 2423 Sum: 20.0oo bp