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