Lab 5

1
Lab 5

• DNA Extraction

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(1) DNA Extraction from Plant Cells Objective
Isolating DNA from plant cells and visualizing it
directly . To extract DNA from plant cells
like strawberry, banana and peas, 1-we need to
(destroy cell wall and cell membrane) 2-we need
to separate DNA from other cell components like
proteins, carbohydrates and lipids through
precipitation. 3-we can collect DNA molecules by
cold alcohol and DNA can be seen
directly. Strawberry character 1- Is octoploid,
meaning that it has 8 copies of each chromosome,
so it has a large amount of nucleic acid. 2-
Fresh fruit contains pectinase and cellulase
enzymes that helps lysing cell wall.
3
Cell organelles and other components can be
separated from each other by centrifugation
1-depending on their physical properties as
size and density. 2-This can be done by using
different speeds at different periods of time.
3-Centrifugation speed is measured by
revolutions per minute (rpm). 4-Bigger and
heavier components precipitate at the bottom and
called pellet, 5-smaller lighter substances
float upper and called supernatant.
Materials (Strawberry or banana or green peas)-
Ice ethanol alcohol 99- Buffer (90ml water 10
ml detergent small amount of NaCl)- large tube-
glass rod.
4
Steps 1- Put fruit in mortar or inside plastic
bag, then mash manually till it becomes
creamy. 2- Add 10 ml of buffer. 3- Leave for 2
min. 4- Filtrate the mixture with piece of Gauze
in glass cone. 5- Discard the precipitant in the
Gauze. And put the liquid filtrate in large tube.
6- Put the glass rod in ice to become iced ,
then put it in the large tube. 7- Pour ice
ethanol alcohol on the glass rod (inside tube)
8- Observe fibers of DNA stuck on the glass
rod. Observation DNA molecules appears as
colorless gelatinous substance sticking to the
glass rod.