Here are the complete sentence answers to the Gel Electrophoresis Questions:
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1. What tool is used to transfer small liquid solutions of DNA from tubes into the gel?
A micropipette is used to transfer small liquid solutions of DNA from tubes into the wells of the gel.
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2. What causes the DNA fragments to move within the gel?
DNA fragments move within the gel because they are negatively charged and are pulled toward the positive electrode when an electric current is applied across the gel.
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3. Which DNA fragments move faster? Which DNA fragments move slower?
Smaller DNA fragments move faster through the gel matrix, while larger DNA fragments move slower because they have more difficulty navigating through the pores of the gel.
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4. What causes the normally colorless DNA to glow under UV light?
The normally colorless DNA glows under UV light because it has been stained with a fluorescent dye, such as ethidium bromide or SYBR Safe, which binds to the DNA and fluoresces when exposed to UV light.
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5. What is the purpose of using a marker or ladder in one lane on your gel?
The purpose of using a marker or ladder in one lane is to provide known DNA fragment sizes that serve as a reference for estimating the sizes of unknown DNA fragments in other lanes by comparing their migration distances.
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6. In the table below, estimate the lengths of DNA fragments in each lane. Lane 8 has your marker and the lengths are written on the right.
*(Based on visual alignment with the marker bands in Lane 8)*
| Sample | DNA Fragment Sizes |
|--------|----------------------------|
| 1 | ~300 bp |
| 2 | ~1000 bp, ~800 bp, ~500 bp, ~100 bp |
| 3 | ~500 bp, ~300 bp |
| 4 | ~500 bp, ~300 bp |
| 5 | ~800 bp, ~500 bp |
| 6 | ~1000 bp, ~300 bp |
| 7 | ~500 bp, ~300 bp |
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Explanation for Question 6:
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Lane 1: One band aligns with the 300 bp marker → estimated size = 300 bp.
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Lane 2: Four bands — top aligns with 1000 bp, next with 800 bp, then 500 bp, bottom with 100 bp.
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Lane 3: Two bands — one near 500 bp, one near 300 bp.
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Lane 4: Two bands — both match approximately 500 bp and 300 bp markers.
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Lane 5: Two bands — upper band slightly above 800 bp (but closest to 800), lower band at 500 bp.
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Lane 6: Two bands — upper at 1000 bp, lower at 300 bp.
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Lane 7: Two bands — upper at 500 bp, lower at 300 bp.
> *Note: Since this is an estimation based on visual comparison, slight variations may occur depending on interpretation, but the goal is to match positions relative to the ladder in Lane 8.*
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✔ All questions answered in complete sentences as requested.
Parent Tip: Review the logic above to help your child master the concept of gel electrophoresis worksheet.
