To isolate DNA from a plant tissue Flashcards
DNA & RNA, Pg183
To begin, what do you add to water to dissolve?
sodium chloride (salt), washing up liquid.
What does adding sodium chloride/salt do?
clump the DNA molecules together.
What does washing up liquid do?
will dissolve the cell and nuclear membranes and release DNA from the cells.
Explain why you chop the onion.
breaks down the cell wall
Add chopped onion to a beaker that contains?
What do you do when both together?
salt/detergent solution,
stir mixture
Beaker in a hot or cold water bath?
What temperature?
For how long?
water bath at 60 degrees C, for 15 mins.
Why water bath the beaker at 60 degrees C?
denatures the enzymes that normally consumes DNA.
Why 15 mins in water bath?
any longer would cause DNA itself to break down
After heating beaker what do you do?
Place in ice water bath, stirring frequently.
How long should beaker be in ice water bath? What does this do?
5 mins, slows down breakdown of DNA.
After ice water bath, what’s next?
Blend mixture for 3 seconds.
What does blending the mixture do?
breaks down cell wall further
Blending mixture for too long would?
break down the DNA strands
After blending what do you do?
filter mixture through coffee filter paper into second beaker.
Why filter mixture?
Cell parts are retained in the filter paper.
After filtering what do you do?
Use syringe with no needle to place some onion filtrate into a boiling tube.
What do you add to boiling tube with onion filtrate? Why?
protease enzyme to break down the protein around the DNA
What do you pour down side of boiling tube?
freezer cold ethanol
What does adding freezer cold ethanol do?
form a layer on top of onion filtrate
What do you do for final step?
Carefully twist a small wire loop in the tube, strands of DNA should attach.
DNA forms a?
clear mesh of what looks like stringy threads.
Difference between coding and non-coding DNA?
coding: has genetic instructions to produce a protein
non-coding: has genetic instructions that do not produce a protein
Why do the following?
- chop kiwi?
- add washing up liquid?
- add salt?
- put in water bath?
- put in ice bath?
- blend mixture?
- filter the mixture?
- add freezer cold ethanol?
- increase surface area, break down the cell walls
- break down the cell membrane/release DNA from nucleus
- clump the DNA
- denatures the enzymes to prevent them from consuimg the DNA
- slows down the breakdown of the DNA
- further break down cell walls
- remove the cell debris from the DNA
- precipitate the DNA/make DNA visible/remove the DNA
Provide a safety precaution for this experiment.
wear safety gloves
wear a lab coat
