Practical report Essay Example | Topics and Well Written Essays - 2000 words

Practical report - Essay Example The contents include fats, carbohydrates and proteins. The enzymes that break apart DNA are thereafter destroyed (Bruns 2007, 50). DNA content is then separated from other cell components. The researcher then precipitates the DNA and re-suspends it in a solution suitable for its studies. When extracting DNA from the cheek cells, saline solution used to rinse the mouth helps to prevent the cells extracted from splitting open or lysing too soon. Centrifugation separates the cheek cells from mouth wash used (Johannson 1972, 39). Spinning the mixture in a centrifuge settles the heavier cells to the bottom of the tube to form pellets. Saline solution pours away, leaving the clumped cheek cells at the bottom of the tube. Lysis buffer added to the cell clump splits open the cells to release DNA from inside the nucleus. The buffer contains soap that dissolves and breaks fatty membranes of the cells, buffer that maintains the pH of the solution and ions that increase osmotic pressure outside the cheek cell and aids in ripping open the cell membrane. Incubation in hot water helps denature cytoplasmic enzymes that break up DNA. Concentrated salt solution changes polarity of the solution under study. DNA elements dissolve in ionic solutions. This is as opposed to other components of the solution; proteins, carbohydrates and fats. ... The process is additionally useful in assessing and distinguishing the variable sizes of alleles. This discerning of allele sizes best takes place with the DNA strands placed at a single locus. Gel Electrophoresis also assesses the quantity and quality of DNA that is present in a sample (Komrakova 2006, 51). This method separates chemical molecules and compounds by charge and size. Substances that are separated are stationed in wells in the agarose gel and an electric field applied. Positively charged molecules and compounds move towards the negative terminal while the negatively charged particles and compounds move towards the positive anode. Larger and longer particles experience difficulty in moving across the mixture to the positive or negative terminal, and are suspended in the gel matrix. Smaller and shorter molecules move easily through the agarose gel matrix and take positions according to their polarity. When strained, the small sized segments form a tight band as they move at relatively the same speed. Type of medium and concentration of the gel determines the gel’s pore size and its ability to segregate same sized fragments. While polyacrylamide gels separate DNA segments differing by a base pair, agarose gels separate fragments of DNA differing by hundreds or more base pairs. Combs forming wells are placed into the gel as it solidifies and cools. The combs are then removed after the gel solidifies. Students can use gel electrophoresis in determining quality and quantity of the DNA matter they extract from their cheek cells. In day-to-day applications, the method is useful in fingerprinting or profiling, DNA sequencing and genetic