In the model of the lesson, a gel was run for 60 minutes…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
In the model of the lesson, a gel was run for minutes. A band of an unknown fragment lies mm from the well, and a second band lies mm from the well. Find the size of each fragment. Give your answer to the nearest whole number of base pairs.
- What is the size of the first fragment?
- What is the size of the second fragment?
- How many times longer is the first fragment than the second?
Need a reminder? The key ideaShow
The enzyme that opens a cell depends on its wall: lysozyme for bacteria, cellulase for plants, chitinase for fungi. Ribonuclease removes RNA, protease removes proteins, and chilled ethanol makes DNA appear. In a gel, DNA moves to the anode, and smaller fragments move farther. In the model of the lesson, distance .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Time min. Distances mm and mm.
Plan. For minutes, distance . We want the size, so .
Step 1. (a) . Size: bp.
Step 2. (b) . Size: bp.
Step 3. (c) times.
Answer: bp; bp; times.
Check. The band that ran farther is the shorter fragment, as it should be.
Watch out. The size is not found by a straight proportion with the distance. The distance is a straight line against the log of the size.
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