1. Describe a medium other than detergent that can play same role and promote for cell walls break down. (2M)

Breaking the cells open, commonly referred to as cell disruption or cell lysis, to expose the DNA within. This is commonly achieved by chemical and physical methods-blending, grinding or sonicating the sample. Lysis refers to the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a lysate. In molecular biology, biochemistry, and cell biology laboratories, cell cultures may be subjected to lysis in the process of purifying their components, as in protein purification, DNA extraction, RNA extraction, or in purifying organelles. Cell disruption is a method or process for releasing biological molecules from inside a cell.

2. Non mechanical technique to get the cell content to get out of the cell/or from the cell membrane. Describe. (5M)-Chemical Permeabilization. -It can be achieved with organic solvents that act by creation of canals through the cell membrane.-EDTA (chelating agent) is widely used for permeabilizaion of Gram megative microorganisms.-Its effectiveness is a result of its ability to bond the divalent cations of Ca++.

3. Describe benefit of adding a teaspoon of salt into the working slurry, then, show the connection of salt as to promote for a basic solution. Name two alkaline agents that act by loosening the rigid structure of a cell wall or membrane. (5M) -Salty water helps the DNA precipitate which solidify and appear when alcohol is added.-It is a positive ion and often associates with negative ions as part of useful compounds.-Sodium dodecylsulphate or SDS is a sodium that contain detergent.-It has the chemical formula of C12H25Na04S. -Two alkali agents include sodium calcium.

4. Describe if you managed to extract chromosomal DNA or plasmid DNA during the lab. Give reasons. (7M)-Plasmid DNA in bacteria usually exists in a ring form in the cytoplasm, separate from the chromosomal DNA in the nucleus.-While chromosomal DNA programs the bacterial cell’s functions and processes, plasmid DNA is often a genetically engineered DNA that codes for a specific genes or genes of interest.-To separate the bacterial chromosomal DNA and sheared DNA from plasmid DNA, sodium hydroxide is often used.

-Chromosomal DNA and shear DNA are both linear, whereas plasmid DNA is circular.-When the solution is basic, for example when sodium hydroxide is added, double stranded DNA molecule separate. This is known as denaturation.-Plasmid DNA molecule, although they are unzipped, they are not separated.-

5. Correlate between plasma membrane, detergent, and bubble happen to be involved during laboratory practice. (5M)-Detergent cleans dishes by removing fats.-Its acts the same way in DNA extraction process which pulling apart the fats (lipids) and proteins that make up the membranes surrounding the cell and nucleus.-Once these membranes are broken apart, the DNA is released from the cell.-Soap molecules are consists of two parts which is head (hydrophilic) and tails (hydrophobic).-Soap molecules organize themselves in bubbles like spheres with heads outside to face the water and tails inside to hide from water.

6. Decide reasons for the use of warm water in the method. What sort of temperature should be used? (3M)- Warm water helps to inactivate (denatures) the deoxyribonuclease enzyme (DNase)

which, if present, would cut the DNA into such small fragments that it would not be visible.

- Temperature used should be around 60- Celcius because most enzyme denatured at 60-Celcius.

7. ‘DNA is not soluble in alcohol’. Using basic organic chemistry knowledge combined with biochemistry knowledge, express the statement in detail. (10M)-Alcohol is less dense than water, so it floats on top forming two separate layers.-All of the protein that broke up in the first two steps will move to the bottom, watery layer.-Then DNA will rise into the alcohol layer from the banana layer.-The cold alcohol helps the DNA precipitate which solidify and appear more quickly.

8. Describe how ‘big’ DNA you may get, or you did get by relating it to the knowledge of genetic involving codons, double stranded DNA and such. (6M)

How big DNA may get is depend on the amount of samples and the amount of DNA extract form the membrane. Cells with more chromosomes contain relatively more DNA, but the difference will not likely be noticeable to the eye. The amount of DNA you will see depends more on the ratio of DNA to cell volume.For example, plant seeds yield a lot of DNA because they have very little water in the cell cytoplasm. That is, they have a small volume. So the DNA is relatively concentrated. The DNA molecule is structurally the same in all living things, including plants and animals. That being said, the product obtained from extraction may look slightly different depending on whether it was extracted from a plant or an animal. For example, the extraction may have more contaminants (proteins, carbohydrates) causing the DNA to appear less string-like, or the amount of DNA that precipitates may vary.

9. Name 3 uses of extracted DNA. (3M)-Used to diagnose man medical conditions -Used for genetic engineering f both plants and animals-Used to gather evidence in a crime investigation-Used for polymerase chain reaction