Introduction to Biology and Essential Clinical Skills Essay

Research question: How can DNA be extracted from a Typical onion tissue in sufficient quantity to be seen and spooled? - Introduction to Biology and Essential Clinical Skills Essay introduction?? Hypothesis: In order to extract DNA from onion cells, a soap detergent, is used as a fat breaker, and used to break through the phosphoric bilateral of the onion cells hence splitting open the cells and spilling their contents out then an alcohol can be used to precipitate the DNA out. Materials: 2 Measuring cylinders Sharp knife Funnel Hot water bath ICC ICE water bath Distilled water Soap detergent Large Onion

NASAL, table salt 1 test tube 95% Ethanol Beaker Method: Set up hot water bath at 55-off C and an ice water bath. For each onion, make a solution consisting of one tablespoon (10 ml) of liquid dishwashing detergent or shampoo and one level 1/4 teaspoon (1. 5 g) of table salt. Put in a I-cup measuring cup (250 ml beaker). Add distilled water to make a final volume of 100 ml. Dissolve the salt by stirring slowly to avoid foaming. Coarsely chop one large onion with a knife and put into a 4-cup measuring cup (1000 ml). For best result TTS, do not chop the onion too finely.

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The size tot the pieces should be like those used in making spaghetti. Cover chopped onion with the 100 ml of solution from step 2. The detergent dissolves the fatty molecules that hold the cell membranes together, which releases the DNA into the solution. Put the measuring cup in a hot water bath at 55-off C for 10-12 minutes. During this time, press the chopped onion mixture against the side of the measuring cup with the back of the spoon. Do not keep the mixture in the hot water bath for more than 15 minutes because the DNA will begin to break down.

Cool the mixture in an ice water bath for 5 minutes. During this time, press the chopped onion mixture against the side of the measuring cup with the back of the spoon. Filter the mixture through a #6 coffee filter or four layers of cheese cloth placed in a strainer over a 4-cup measuring cup. When pouring the mixture into the strainer, avoid letting foam get into the measuring cup. Dispense the onion solution into a test tube. The test tube should contain about 1 teaspoon of solution or be about 1/3 full, whichever is less.

For better results, stir the solution recently when dispensing it into the tubes. Add cold alcohol to the test tube to create an alcohol layer on top of about 1 CM. For best results, the alcohol should be as cold as possible. The alcohol can be added to the solution in at least three ways. (a) Fill a Pasteur pipette with alcohol, put it to bottom of the test tube, and release the alcohol. (b) Put about 1 CM of alcohol into the bottom of a test tube and add the onion solution. (c) Slowly pour the alcohol down the inside of the test tube with a Pasteur pipette or medicine dropper.

Results: A white precipitate is formed into the alcohol layer in a ring form. Conclusion and Evaluation: The white precipitate is the DNA, this supports the hypothesis because the liquid detergent broke the lipid bilateral of the onion cells pouring out its contents and since DNA is insoluble in alcohol every other component in the mixture except from DNA stayed in the solution while DNA (the white precipitate) is precipitated into the alcohol layer. And if the experiment was carried out accordingly there should be enough DNA to spool onto a glass rod or any similar device.

Biology Lab Report Essay

Iodine is a test for starch while Benedict’s solution is a test for reducing sugars - Biology Lab Report Essay introduction. When solution A is tested by benidicts test, the clear blue solution changed to a little reddish and brick red precipitate is formed. this result show that solution A is a reducing sugar. When carried out iodine test with solution A, the colourless solution remain unchanged . this tell us that starch is absent is solution A. When solution B is tested with Benedicts test, the clear blue solution remain unchanged, we can conclude that it is a non reducing sugar.

When tested with iodine test, the colourless solution changed to dark blue colour. this show that starch is present in solution B. From the above test, we can conclude that solution B is a starch solution so we can use it to carry out the next test. solution B , saliva and hydrochloric acid was used in the second test. The enzyme involed in this test is salivary amylase which can found in saliva. Salivary Amylase, is called ptyalin it’s to break down starch to sugar. Things we ate is broken down in mouth by amylase. Amylase hydrolysed starch into a reducing sugar which can give beneduct test a positive result.

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Body temperature is the optimal temperature for the action of amylase. Enzymes are catalysts for any reactions. They provide an alternative way of lower activation energy to speed up the reaction. When the temperature is low, the kinetic energy of substrate and enzyme is low, this take long time for both of the substance to bind together so the rate of reaction is low. When the temperature is high, the kinetic energy of the substance and enzyme is high too. The substrate and enzyme collide more often with each other. The rate of the both substance to bind is increase too.

When the temperature reach optimal, the kinetic energy and collision increase but the rate of the substrate-enzyme bind to form is decrease because the amino acid in the molecule vibrate strongly. When the temperature is too high and exceed the optimum temperature for the enzyme to react, the thermal energy will cause the enzyme to denature. The high temperature break the hydrogen bond which hold the tertiary and secondary structure of the enzyme, the enzyme lose its shape and the substrate cannot bind to the active site anymore.

HCl is to catalyst the organic proses. Starch is make up with a long chain of sugar molecules by glycosidic bond. The bond can be broken through hydrolysis to release glucose. The simple sugar, glucose can be separated by HCl. Hydrochloric acid add H+ in the solution and thus hydrolysis occur. When Hcl add to solution B, it hydrolyse carbohydrate to sugar. And it give Benedict test a positive result meaning that redusing sugar is present. But the hydrolysis with hcl can only occur if the temperature is high enough for the reaction to occur.

When the miture of solution B and Hcl was incubate at 37C the result remail unchanged because the starch molecule not been broken down yet. When solution B mixed with same amout of saliva, and incubate at 37c for 5 mins, it change the clear blue solution to opaque green and red precipitate is formed. This result show that a small quantity of sugar is present in the solution. The amylase in saliva hydrolyse starch in solution B to a reducing sugar. After incubate a t the same temperature the same solution of solution b and saliva for 35mins, the clear blue solution change to opaque green which indicate that sugar is present.

This result means that a temp of 37 is suitable for amylase to hydrolyse the starch into glucose. Incubation of solution b plus hcl at 37c for 5mins give a negative result of Benedict test. The blue solution remain unchanged. there is no sugar present in the solution whch mean that hcl does not hydrolye starch in solution b . after 35 mins of incubation of 37c, the bliue solution remain unchnage too. The starch does not be hydrolysed by hcl. This result show that the temperature is not suitable for hydrolysis between hcl and starch.

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