...BIOL2103 Biological Sciences Laboratory Course Practical 3 Laboratory manual Isolation of nucleic acid and spectrophotometry Introduction: The ability to isolate and quantify nucleic acids accurately and rapidly is a prerequisite for many of the methods used in biochemistry and molecular biology. The concentration of DNA or RNA in a sample, and its condition, are often estimated by running the sample on an agarose gel. Such concentration estimates are semiquantitative at best and are time-consuming. For a more accurate determination of the concentration of DNA or RNA in a sample, a UV spectrophotometer is commonly used. Spectrophotometry uses the fact that there is a relationship between the absorption of ultraviolet light by DNA/RNA and its concentration in a sample. The absorption maximum of DNA/RNA is approx 260nm. The purity of a solution of DNA can be determined using a comparison of the optical density values of the solution at various wavelengths. For pure DNA, the observed A260/A280 ratio will be near 1.8. Elevated ratios usually indicate the presence of RNA. The A260/A280 ratio is used to assess RNA purity. An A260/A280 ratio of 1.8-2.1 is indicative of highly purified RNA. The 260/280 ratio below 1.8 often signal the presence of a contaminating protein or phenol. Alternatively, protein or phenol contamination is indicated by 230/260 ratios greater than 0.5. Workflow Time 2 days before the lab session During lab session 1:30 pm Task Cell...
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...g A New Molecule of Life Life as we know it is far more complex than one can imagine. The smallest molecule in human body can play a large role in determining the genetic outcome or the overall well being of a person. In Peter Nielsen’s “Designing a New Molecule of Life”, he speaks of a molecule that hopefully one day will create a scientific and medical breakthrough. In this essay you will read a summary of Peter Nielsen’s article and the research he has done with this molecule. Peter Nielson, along with many other scientists, have spent years creating and experimenting with a synthetic molecule called peptide nucleic acid (PNA). PNA is an artificial polymer that has many similarities to deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It has the same storing features as DNA and RNA while being built on a protein based backbone therefore making it sturdier and simpler than the sugar phosphate-backbone. The molecule was created in hopes of having an immediate affect by pursuing a drug that would target DNA’s composing specific genes, to either enhance or block the gene’s expression. This new drug would be in efforts to interfere with the production of disease producing proteins. Although this molecule has produced highly anticipated medical research, it has also lead to speculations of being the origins of life. In his years of research, Peter Nielsen and his colleagues wanted to achieve the ability of PNA recognizing double-stranded or duplex DNA having specific...
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..._ However, the helix structure (to be more specificly, the glycosidic bonds) is easily wrecked by heat (boiling temperature of water) and acid treatment (HCl). Once the helix structure of homopolycarbohydrate is broken, the conformation with iodine no longer exists. It leads to the gradual loss of blue color. | 2 | | | 4 | | | 6 | | | 8 | | | 10 | | | | No color change | | Color of Lugol | | | 2.PROTEINS 2.2.2. Task-Qualitative Detection of Proteins Protein solution | Original color | After 10% NaOH | After 0.5% CuSO4 | 1. Egg albumin | Colorless | Colorless | Blue->purple | 2. Fresh cow milk | White | White | Blue->purple | Explanation: NaOH doesn’t react with Proteins, so there’s no change to the protein solutions Next, when CuSO4 is added, it reacts with NaOH to form Cu(OH)2 (blue) first. 2NaOH+ CuSO4 -> Cu(OH)2(s) + Na2SO4 Then Cu(OH)2 and Proteins together form the complex, which gives out the purple color. This reaction (called biuret reaction) is useful to detect the protein presence. (write down the chemical equation, GOOGLE) 3. LIPIDS 4. NUCLEIC ACIDS 4.1.General Introduction Nucleic acids are large biological molecules essential for all known forms of life. They include DNA (deoxyribonucleic acid) and RNA(ribonucleic acid). Together with proteins, nucleic acids are the most important biological macromolecules; each is found in abundance in all living things, where they function in encoding, transmitting...
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...What biological principle is illustrated by the Heike crabs? Selection by humans Sagan says that if artificial selection can produce vast changes in a short period of time, then what must nature be able to do, given the age of the ear (4.5 billion years or so)? Don't just quote the video here. Explain what he means! Nature must be able to produce and create. What are the basic “steps” in natural selection as Sagan describes them? What questions does he raise for you? Natural Selection happens when human’s changes have created other changes without humans directly deciding to do so. Sagan describes the basic steps as there are more creatures then can survive. Less adapted have a less chance of surviving and producing off spring. Sudden changes in heredity can be pushed on to the off springs. Environmental changes can have an impact on what mutations will help survival. Thus, slow changes produce new species. Natural Selection was discovered by Charles Darwin and Alfred Russel Wallace. Explain the Watchmaker Hypothesis as an argument against natural selection. How does Sagan address it? “Our ancestors looked at the intricacy and the beauty of life and saw evidence for a great designer. The simplest organism is a far more complex machine than the finest pocket watch. And yet, pocket watches don’t spontaneously self-assemble or evolve in slow stages on their own from say, grandfather clocks”. (Sagan, C) It’s impossible to just look at something and understand...
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...Nucleic Acids Competency 208.5.1 Melissa Kelleher, RN The Structure of DNA • DNA is composed of units called nucleoCdes, (Wolfe, 2000). • NucleoCdes are composed of a phosphate group, a deoxyribose sugar, and a nitrogenous base, (Wolfe, 2000). – Purines – nitrogenous bases that composed of two rings, (Wolfe, 2000). – Pyrimadines – nitrogenous bases composed of one ring, (Wolfe, 2000). The Structure of DNA • DNA is a double helix structure of nucleoCdes wound together in an anCparallel direcCon, (Wolfe, 2000). – Hydrogen bonds form between the nitrogenous bases, (Wolfe, 2000). – Base pairs only bond in specific pairs, (Wolfe, 2000). • Adenine bonds only with thymine, (Wolfe, 2000). • Guanine bonds only with cytosine, (Wolfe, 2000). • Deoxyribose sugars line up in one direcCon, considered the 51 to 31 direcCon, in one strand of DNA, and in the opposing direcCon, considered the 31 to 51 direcCon...
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