Question

Resuspend the DNA in \(1000 \mu \mathrm{L}\) isopropanol using a nonsterile transfer pipette, then spin it in a minicentrifuge for a few seconds. The DNA should be at the bottom of the tube.

Short answer

Add 1000 µL isopropanol, mix, centrifuge for a few seconds, and the DNA will be at the bottom.

Step-by-step solution

- Resuspend DNA in Isopropanol

Using a nonsterile transfer pipette, carefully add exactly 1000 µL of isopropanol to the tube containing the DNA. Ensure that the DNA is fully submerged in the isopropanol.

- Mix the Solution

Gently mix the solution to ensure the DNA is evenly resuspended in the isopropanol. This can be done by gently pipetting up and down or by flicking the tube.

- Centrifuge the Mixture

Place the tube in a minicentrifuge and spin it for a few seconds. This allows the DNA to pellet at the bottom of the tube due to the centrifugal force.

- Identify the DNA Pellet

After spinning, carefully remove the tube from the centrifuge. The DNA should be visible as a small pellet at the bottom of the tube.

Key concepts

DNA isolation

DNA isolation is a critical process in molecular biology. It involves extracting DNA from cells or tissues, allowing scientists to study genetic material. The process usually starts with breaking open the cells using a buffer. This step releases the DNA from the nucleus. Proteins and other cell debris are then removed. Finally, the DNA is purified and collected for further use. The quality of isolated DNA is crucial for downstream applications like PCR and sequencing.

centrifugation

Centrifugation is a laboratory technique that uses centrifugal force to separate substances of different densities. Here's how it works:

• The mixture is placed in a centrifuge tube.
• The tube is spun at high speeds.
• Heavier particles move to the bottom, forming a pellet.

In the DNA resuspension protocol, centrifugation is used to pellet DNA at the bottom of the tube. This helps to concentrate the DNA, making it easier to see and work with in subsequent steps.

isopropanol precipitation

Isopropanol precipitation is a common method to purify and concentrate DNA. Isopropanol helps by precipitating the DNA, making it form a solid pellet. Here's a simplified explanation:

• DNA is mixed with isopropanol.
• The mixture is then centrifuged.
• DNA forms a pellet that can be separated from the liquid.

This method is preferred because it's quick and effective. Additionally, isopropanol is less flammable compared to other alcohols like ethanol, making it safer in the lab.

laboratory techniques

Understanding various laboratory techniques is essential for carrying out DNA isolation and resuspension protocols effectively. Some fundamental techniques include:

• Using pipettes to measure and transfer liquids accurately.
• Employing centrifuges for separating substances based on density.
• Mixing solutions properly to ensure homogeneity.

Mastery of these techniques ensures reliability and reproducibility in experiments. It also helps in achieving high-quality results that are crucial for downstream applications.