Assignment: DNA Extraction Lab Report

Assignment: DNA Extraction Lab Report

DNA extraction and polymerase chain reaction (PCR) are the basic techniques employed in the molecular laboratory. This short overview covers various physical and chemical methods used for DNA extraction so as to obtain a good-quality DNA in sufficient quantity. DNA can be amplified with the help of PCR. The basic principle and different variants of PCR are discussed.

Keywords: DNA extraction, Polymerase chain reaction, real time PCR
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DNA Extraction
DNA extraction is a method to purify DNA by using physical and/or chemical methods from a sample separating DNA from cell membranes, proteins, and other cellular components. Friedrich Miescher in 1869 did DNA isolation for the first time.

The use of DNA isolation technique should lead to efficient extraction with good quantity and quality of DNA, which is pure and is devoid of contaminants, such as RNA and proteins. Manual methods as well as commercially available kits are used for DNA extraction. Various tissues including blood, body fluids, direct Fine needle aspiration cytology (FNAC) aspirate, formalin-fixed paraffin-embedded tissues, frozen tissue section, etc., can be used for DNA extraction.

DNA extraction involves lysing the cells and solubilizing DNA, which is followed by chemical or enzymatic methods to remove macromolecules, lipids, RNA, or proteins.

DNA extraction techniques include organic extraction (phenol–chloroform method), nonorganic method (salting out and proteinase K treatment), and adsorption method (silica–gel membrane).

Organic extraction
This method is labor intensive and time consuming.

Cell lysis can be done using nonionic detergent (sodium dodecyl sulfate), Tris–Cl, and Ethylene diamine tetraacetic acid (EDTA), and this step is followed by removal of cell debris by centrifugation. Protease treatment is then used to denature proteins. Organic solvents such as chloroform, phenol, or a mixture of phenol and chloroform (phenol/chloroform/isoamyl alcohol ratio is 25:24:1) are used for denaturation and precipitation of proteins from nucleic acid solution, and denatured proteins are removed by centrifugation and wash steps. RNAse treatment is done for the removal of unwanted RNA. Precipitation with ice-cold ethanol is performed for concentrating DNA. Nucleic acid precipitate is formed, when there is moderate concentration of monovalent cations (salt). This precipitate can be recovered by centrifugation and is redissolved in TE buffer or double-distilled water.

Other methods include silica-based technology (DNA absorbs to silica beads/particles at a specific pH in presence of specific salts), magnetic separation (DNA binds reversibly to magnetic beads, which are coated with DNA-binding antibody), anion exchange technology, salting out, and cesium chloride density gradients.

Assessing the quality and yield of DNA: The quality and yield of DNA are assessed by spectrophotometry or by gel electrophoresis. Spectrophotometry involves estimation of the DNA concentration by measuring the amount of light absorbed by the sample at specific wavelengths. Absorption peak for nucleic acids is at ~260 nm. The A260/A280 ratio is ~1.8 for dsDNA. A ration of less than 1.7 indicates protein contamination.

Important information for writing discussion questions and participation

Welcome to class

Hello class and welcome to the class and I will be your instructor for this course. This is a -week course and requires a lot of time commitment, organization, and a high level of dedication. Please use the class syllabus to guide you through all the assignments required for the course. I have also attached the classroom policies to this announcement to know your expectations for this course. Please review this document carefully and ask me any questions if you do. You could email me at any time or send me a message via the “message” icon in halo if you need to contact me. I check my email regularly, so you should get a response within 24 hours. If you have not heard from me within 24 hours and need to contact me urgently, please send a follow up text to

I strongly encourage that you do not wait until the very last minute to complete your assignments. Your assignments in weeks 4 and 5 require early planning as you would need to present a teaching plan and interview a community health provider. I advise you look at the requirements for these assignments at the beginning of the course and plan accordingly. I have posted the YouTube link that explains all the class assignments in detail. It is required that you watch this 32-minute video as the assignments from week 3 through 5 require that you follow the instructions to the letter to succeed. Failure to complete these assignments according to instructions might lead to a zero. After watching the video, please schedule a one-on-one with me to discuss your topic for your project by the second week of class. Use this link to schedule a 15-minute session. Please, call me at the time of your appointment on my number. Please note that I will NOT call you.

Please, be advised I do NOT accept any assignments by email. If you are having technical issues with uploading an assignment, contact the technical department and inform me of the issue. If you have any issues that would prevent you from getting your assignments to me by the deadline, please inform me to request a possible extension. Note that working fulltime or overtime is no excuse for late assignments. There is a 5%-point deduction for every day your assignment is late. This only applies to approved extensions. Late assignments will not be accepted.

If you think you would be needing accommodations due to any reasons, please contact the appropriate department to request accommodations.

Plagiarism is highly prohibited. Please ensure you are citing your sources correctly using APA 7th edition. All assignments including discussion posts should be formatted in APA with the appropriate spacing, font, margin, and indents. Any papers not well formatted would be returned back to you, hence, I advise you review APA formatting style. I have attached a sample paper in APA format and will also post sample discussion responses in subsequent announcements.

Your initial discussion post should be a minimum of 200 words and response posts should be a minimum of 150 words. Be advised that I grade based on quality and not necessarily the number of words you post. A minimum of TWO references should be used for your initial post. For your response post, you do not need references as personal experiences would count as response posts. If you however cite anything from the literature for your response post, it is required that you cite your reference. You should include a minimum of THREE references for papers in this course. Please note that references should be no more than 5 years old except recommended as a resource for the class. Furthermore, for each discussion board question, you need ONE initial substantive response and TWO substantive responses to either your classmates or your instructor for a total of THREE responses. There are TWO discussion questions each week, hence, you need a total minimum of SIX discussion posts for each week. I usually post a discussion question each week. You could also respond to these as it would count towards your required SIX discussion posts for the week.

I understand this is a lot of information to cover in 5 weeks, however, the Bible says in Philippians 4:13 that we can do all things through Christ that strengthens us. Even in times like this, we are encouraged by God’s word that we have that ability in us to succeed with His strength. I pray that each and every one of you receives strength for this course and life generally as we navigate through this pandemic that is shaking our world today. Relax and enjoy the course!

Hi Class,

Please read through the following information on writing a Discussion question response and participation posts.

Contact me if you have any questions.

Important information on Writing a Discussion Question

• Your response needs to be a minimum of 150 words (not including your list of references)
• There needs to be at least TWO references with ONE being a peer reviewed professional journal article.
• Include in-text citations in your response
• Do not include quotes—instead summarize and paraphrase the information
• Follow APA-7th edition
• Points will be deducted if the above is not followed

Participation –replies to your classmates or instructor

• A minimum of 6 responses per week, on at least 3 days of the week.
• Each response needs at least ONE reference with citations—best if it is a peer reviewed journal article
• Each response needs to be at least 75 words in length (does not include your list of references)
• Responses need to be substantive by bringing information to the discussion or further enhance the discussion. Responses of “I agree” or “great post” does not count for the word count.
• Follow APA 7th edition
• Points will be deducted if the above is not followed

• Remember to use and follow APA-7th edition for all weekly assignments, discussion questions, and participation points.
• Here are some helpful links
• The is a great resource