Lab 5 DNA Extraction 1 DNA Extraction from

Lab 5 DNA Extraction

(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.

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 (90 ml water +10 ml detergent +small amount of Na. Cl)- large tube- glass rod.

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.