Name: steps in dna extraction
Uploaded: 2026-08-26T08:20:38.799Z
Duration: 1 min 58 s
Channel: JoVE

DNA extraction is the process of removing and purifying DNA from cells.First, cells are lysed or broken open, usually through a combination of physical disruption and treatment with chemicals such as detergents that dissolve the cell and nuclear membranes.The cellular contents are then released into the solution.Next, the DNA is separated from the other molecules present in the sample.Protease enzymes are added to degrade proteins, followed by RNase treatment to degrade RNA while leaving the DNA intact.Following this, phenol and chloroform are added to separate DNA from proteins and other cellular components. The sample is centrifuged to separate the aqueous and organic phases. Because DNA is water-soluble, it remains in the aqueous layer, while proteins and cellular debris remain in the organic phase.The aqueous layer containing the DNA is then collected, and salt is added. The positively charged ions from the salt neutralize the negatively charged phosphate groups in the DNA backbone.Then, ice-cold ethanol is added. Because DNA is much less soluble in ethanol than in water, the neutralized DNA molecules clump together and precipitate out of the solution.The DNA precipitate is centrifuged, causing it to settle at the bottom of the tube and form a pellet.After washing and resuspending the DNA pellet in a buffer solution, the extracted DNA can be used in research or biotechnology applications.

dna isolation

DNA Isolation

DNA from cells is required for many biotechnology and research applications, such as molecular cloning. To remove and purify DNA from cells, researchers use various methods of DNA extraction. While the specifics of different protocols may vary, some general concepts underlie the process of DNA extraction.

<h4>The Process</h4>

First, cells need to be lysed&#x2014;broken open&#x2014;to release the DNA into solution. Cells can be physically lysed using equipment such as a homogenizer, sonicator, or bead beater, which grind or otherwise apply force to break the cells open. Often, substances such as detergent are added during lysis to chemically disrupt the lipid-based cell membranes&#x2014;helping release the DNA from the nucleus and cell. The spinning in a centrifuge sediments the cell debris to the bottom, and the lysate&#x2014;containing cellular materials&#x2014;is collected for further processing.

The DNA must then be separated from other cellular molecules, such as RNA and proteins. Therefore, enzymes such as RNase and Proteinase K are often added during or after lysis to degrade RNA and proteins, respectively. Additionally, organic solvents such as phenol and chloroform are commonly used to separate DNA from protein. Typically, the sample is vortexed with phenol-chloroform and then centrifuged to separate the aqueous and organic phases in the tube. The DNA-containing aqueous phase at the top can then be pipetted off, leaving behind the protein in the organic phase.

Salts are often added during DNA extraction to stabilize the DNA and assist in precipitating it out of solution. A standard method of DNA precipitation is to add ice-cold alcohol, such as ethanol or isopropanol, to the sample. This causes the DNA to form a white, cloudy precipitate within the liquid in the tube.

The sample is then spun in a centrifuge, causing the DNA precipitate to collect at the bottom of the tube as a pellet. The pellet is washed by removing the liquid, washing in alcohol, and spinning it again. After the final wash, the pellet is re-suspended in a buffer&#x2014;creating an aqueous solution of purified DNA that is ready to be studied or used in biotechnology.

DNA from cells is required for many biotechnology and research applications, such as molecular cloning. To remove and purify DNA from cells, researchers ...

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steps in dna extraction

DNA extraction is the process of removing and purifying DNA from cells. It is used in many biotechnology and research applications, including molecular cloning. The main goal is to free DNA from the cell and prepare it for later study or use.

The first step is cell lysis, which means breaking cells open. Researchers may use a homogenizer, sonicator, or bead beater to physically lyse the cells. They also often add detergent to chemically disrupt the lipid-based cell membranes. This helps release DNA from the nucleus and the rest of the cell.

After lysis, the sample is spun in a centrifuge. This causes cell debris to settle at the bottom, while the liquid lysate is kept for the next steps. The DNA then has to be separated from other cellular molecules, such as RNA and proteins. Enzymes like RNase and Proteinase K are often added to break down RNA and proteins, and phenol-chloroform can be used to separate DNA from protein.

During the phenol-chloroform step, the sample is vortexed and centrifuged again. The tube separates into an aqueous phase and an organic phase. The DNA stays in the aqueous phase at the top, and this layer can be pipetted off. Salts are often added to help stabilize the DNA and support precipitation.

To collect the DNA, ice-cold alcohol such as ethanol or isopropanol is added. The DNA then forms a white, cloudy precipitate in the tube. Another centrifuge spin pulls this DNA into a pellet at the bottom. The pellet is washed with alcohol, spun again, and then re-suspended in buffer to make a purified DNA solution ready for biotechnology work.

Steps in DNA Extraction

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DNA extraction is the process of removing and purifying DNA from cells. It is used in many biotechnology and research applications, including molecular cloning. The main goal is to free DNA from the cell and prepare it for later study or use. The first step is cell lysis, which means breaking cells open. Researchers may use a homogenizer, sonicator, or bead beater to physically lyse the cells. They also often add detergent to chemically disrupt the lipid-based cell membranes. This helps...

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key terms and concepts

Learn the main steps in DNA extraction, including cell lysis, centrifugation, protein removal, and DNA precipitation for purified samples.

Steps in DNA Extraction | JoVE K12

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Steps in DNA Extraction

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