1. What does the salt do? (Salt provides the
DNA with a favorable environment; it contributes
positively charged atoms that neutralize the normal
negative charge of DNA.)
2. What does the blender do? (help break down
the cell walls)
3. When you mix the blended cell source with the
soap, what is happening? (In the experiment,
the enzymes in the soap are breaking down the lipid
molecules of the cell and nuclear membranes, releasing
the contents of the cell, including the DNA. These
enzymes in the soap are what break down grease while
4. What does the alcohol do? Why does the DNA rise
to the top after adding alcohol? (DNA will not
dissolve in this alcohol, so the DNA comes out of
the solution, or precipitates. It is less dense
than water or cell scum--which is what settles to
the bottom of the glass--so it floats up into the
alcohol layer, where you see it as a snotty, string-like
substance, with small bubbles formed on it.)
5. If you try a seed food such as peas, there will
be more protein residue in the liquid. Why? (Because
protein is stored in them for the nutrition of the
6. Why cant you see the double helix?
(It is too small to be seen with the naked eye.
What you extracted is millions of strands of DNA.)
7. What part of the cell did the DNA come from?
(99% is from the nucleus.)
1. If you did the experiment with both plant and
animal cells, how do their DNA compare?