To isolate DNA from a plant tissue

Question 1

To begin, what do you add to water to dissolve?

Answer 1

sodium chloride (salt), washing up liquid.

Question 2

What does adding sodium chloride/salt do?

Answer 2

clump the DNA molecules together.

Question 3

What does washing up liquid do?

Answer 3

will dissolve the cell and nuclear membranes and release DNA from the cells.

Question 4

Explain why you chop the onion.

Answer 4

breaks down the cell wall

Question 5

Add chopped onion to a beaker that contains?
What do you do when both together?

Answer 5

salt/detergent solution,
stir mixture

Question 6

Beaker in a hot or cold water bath?
What temperature?
For how long?

Answer 6

water bath at 60 degrees C, for 15 mins.

Question 7

Why water bath the beaker at 60 degrees C?

Answer 7

denatures the enzymes that normally consumes DNA.

Question 8

Why 15 mins in water bath?

Answer 8

any longer would cause DNA itself to break down

Question 9

After heating beaker what do you do?

Answer 9

Place in ice water bath, stirring frequently.

Question 10

How long should beaker be in ice water bath? What does this do?

Answer 10

5 mins, slows down breakdown of DNA.

Question 11

After ice water bath, what’s next?

Answer 11

Blend mixture for 3 seconds.

Question 12

What does blending the mixture do?

Answer 12

breaks down cell wall further

Question 13

Blending mixture for too long would?

Answer 13

break down the DNA strands

Question 14

After blending what do you do?

Answer 14

filter mixture through coffee filter paper into second beaker.

Question 15

Why filter mixture?

Answer 15

Cell parts are retained in the filter paper.

Question 16

After filtering what do you do?

Answer 16

Use syringe with no needle to place some onion filtrate into a boiling tube.

Question 17

What do you add to boiling tube with onion filtrate? Why?

Answer 17

protease enzyme to break down the protein around the DNA

Question 18

What do you pour down side of boiling tube?

Answer 18

freezer cold ethanol

Question 19

What does adding freezer cold ethanol do?

Answer 19

form a layer on top of onion filtrate

Question 20

What do you do for final step?

Answer 20

Carefully twist a small wire loop in the tube, strands of DNA should attach.

Question 21

DNA forms a?

Answer 21

clear mesh of what looks like stringy threads.