Experiment Questions

DNA Isolation

DNA Isolation

For what purpose did you use washing-up liquid while extracting DNA from plant tissue ?

To break down membranes

DNA Isolation

For what purpose did you use freezer-cold ethanol while extracting DNA from plant

tissue ?

To separate (or see) the DNA

DNA isolation

For which purpose did you use washing-up liquid or other detergent while extracting DNA

from plant tissue?

To break down membranes

DNA Isolation

For which purpose did you use freezer-cold ethanol while extracting DNA from plant

tissue.

To separate (or see) the DNA

DNA Isolation

In one of your laboratory activities you isolated DNA from a plant tissue. Where in plant cells

is DNA found?

Nucleus OR Chloroplasts OR Mitochondria

DNA Isolation

It is usual to chop the tissue and place it in a blender.

(i) Suggest a reason for this.(ii) For how long should the blender be allowed

to run? (i) Break up of cell (walls) or release of

cytoplasm (ii) 3 seconds only

DNA Isolation

Washing-up liquid is normally used in this experiment. What is its function?

To break down membrane(s) or membrane components

DNA Isolation

Explain why Sodium chloride (salt) is used.

Clumps (protects) DNA / To remove protein / Separates DNA / Separates protein

DNA Isolation

(i) What is a protease enzyme? (ii) Why is a protease enzyme used in this

experiment?

(i) Breaks down (acts on) protein (ii) Proteins are associated with DNA or

chromosomes

DNA Isolation

The final separation of the DNA involves the use of alcohol (ethanol). Under what condition is

the alcohol used?

Ice cold

DNA Isolation

For which purpose did you use washing-up liquid or other detergent while extracting DNA

from plant tissue?

Detergent breaks down membranes

DNA Isolation

For which purpose did you use freezer-cold ethanol while extracting DNA from plant

tissue?

To separate (or see) the DNA

DNA Isolation

Having obtained a plant tissue e.g. onion, kiwi, etc.(i) What was the first procedure that you followed?

(ii) What was the reason for that procedure?

(i) Chop(ii) To disrupt structure (or described) or to

increase surface area

DNA Isolation

Washing-up liquid is used in the isolation. Give a reason for its use.

To disrupt membranes

DNA Isolation

Salt (sodium chloride) is used in the isolation. Give a reason for its use.

To clump the DNA (or described) or to protect DNA from other positive ions

DNA Isolation

(i) What is a protease? (ii) Why is a protease necessary when isolating

DNA?

(i) An enzyme that digests protein (ii) Because DNA is combined with protein

DNA Isolation

The final stage of the isolation involves the use of freezer-cold ethanol.

(i) Describe how it is used. (ii) For what purpose is it used?

(i) Added slowly down the side of the test tube

(ii) To bring the DNA out of solution

DNA Isolation

Give one reason why you first chopped the plant material into very small pieces.

To increase surface area or to burst cells or to break cell walls

DNA Isolation

Detergent and salt were added to the chopped plant material, which was then heated.

How was this mixture heated?

In a water bath

DNA Isolation

Detergent and salt were added to the chopped plant material, which was then heated.

Why was this mixture heated?

To inactivate enzymes

DNA Isolation

Later in the activity the mixture was blended for a maximum of 3 seconds.

What would happen to the DNA if the mixture was blended for longer than 3 seconds?

It would be shredded

DNA Isolation

Protease was added to the mixture. Why was protease added?

To digest the protein (in the chromosomes)

DNA Isolation

The heated mixture of plant cells, detergent and salt was blended and then filtered.

After filtration, where was the DNA of your plant tissue to be found?

In the filtrate

DNA Isolation

What should you do after the filtration to make the DNA visible?

Add freezer-cold ethanol or alcohol

DNA Isolation

Detergent and salt were added to the chopped plant material, which was then heated. Explain why the detergent was used.

To break down cell membranes or to burst cells

DND Isolation

What plant did you use?

Onion or Kiwi or other suitable plant

DNA Isolation

Where in plant cells is DNA found?

Nucleus or chloroplasts or mitochondria