Chemical Aspects of Life

Hyphotesis

In this section i will be discussing my thoughts of the chemical aspects of life. Explaining what my hypotheses are, for what chemicals are in which substances and what affects the reagents will have on them. Protein testing will be performed on 2 substances,egg albumin and gelatin using Biuret’s solution. If biuret’s solution is added to egg albumin then the egg albumin will change colors. If biuret’s solution is added to gelatin then there will be only the color of the biuret’s solution in there.

When testing for lipids using the grease spot test three substances will be left to dry on a brown paper bag square lipids will appear in the form of a stain on the paper bag. If oil is left to dry on a paper bag then very evident stain will appear. If milk is left to dry on a paper bag then a residue will be left on top of the bag. When testing for lipids Using Sudan IV an oil and water test will be conducted, and an milk and water test will be done. If oil and water are tested using sudan IV then the oil will mix with the sudan IV. If milk and water are tested using Sudan IV then the Sudan Iv will not mix with either.

When testing for carbohydrates benedict’s solution will be used and Hcl will be used as an additive to alter results. If benedict’s is added to glucose then the solution will change color. If benedict’s solution is added to sucrose then the solution will change color. If benedict’s solution is added to sucrose and Hcl there will be a more drastic color change. If benedict’s solution is added to milk then there will be a slight color change. If benedict’s solution is added to Hcl and milk there will be a drastic color change. If benedict’s solution is added to starch then there will be a color change.

If benedict’s solution is added to starch and Hcl then there will be a more drastic color change. When testing for carbohydrates using iodine a porcelain spot plate will be used to better see color changes. If iodine is added to a starch solution then it will change color. If iodine is added to water then the iodine will become dilute.

Procedure:

You will be testing for the presence of the following subtances: proteins, lipids, and carbohydrates. The carbohydrates will include monocaccharides (glucose), disaccharides (sucrose), and polysaccharides (starch).

Protein test Background: Proteins give color reactions with certain reagents. The compounds that give rise to these colors are formed not by the whole protein molecule but by certain amino acids present in the protein. Biuret solution will be used for the test. Biuret solution is a blue solution that turns a violet color in the presence of proteins this color change occurs when the Biurets reacts with the amino groups found in the amino acids that are the building blocks of proteins. add 3ml of dilute egg albumin solution to a test tube. Add biuret’s solutiong drop by drop.

Stop if a violet color is obtained. Do not continue until a blue color occurs repeat the test with gelatin. Record your results. Lipid test Background: Lipids are insoluble in water but are soluble in fat solvents such as ether, acetone, and carbon tetrachloride. The simplest lipids are composed of carbon, hydrogen and oxygen. Lipids will remain on a brown paper bag after the water in the solution has evaporated, this will make the bag somewhat transparent. Secondly, a dye test will be done. In this test, dark red sudan IV will be used.

Sudan IV is not soluble in water, but is soluble in lipids. You will be observing the distribution of dye in this test. Procedure: with a medicine dropper, add a drop of salad oil to the corner of a brown paper bag. To the opposite corner, add a drop of water. To one more corner, add a drop of milk. Let the fluids evaporate and then examine each spot by holding the paper to the light look for areas of transperency. Record your results Procedure: Add 3ml of water to a test tube. Add 1ml of oil to the same test tube. Do not shake. Now add 2 drops of sudan Do not shake

Observe the distribution of the dye with respect to the water and oil. Record your results. Repeat this test using milk instead of oil. Record your results.

Carbohydrate test

Background: sugar starch and cellulose are common examples of carbohydrates. Carbohydrates are made up of the base elements c, h, and o in a 1:2:1 ratio. The simplest carbohydrates are monosaccharides (simple sugars such as glucose). Monosaccharides have just one carbon ring and are the building blocks of larger sugar molecules. Disaccharides, like sucrose, have two carbon rings. They are formed when two monosaccharides join together.

Examples include: Maltose (glucose + glucose); Lactose (glucose + galactose); and sucrose (glucose + fructose). Polysaccharides have three or more carbon rings. Starch is an example of a polysaccharide. Procedure: put 3ml of benedict’s solution in a test tube. Add 2ml of 5% glucose solution. Carefully place the tube in a boiling water bath for 2 minutes. Remove the tube amd allow it to cool. Record the color reoeat the test with 3ml of benedict’s solution and 2ml of 5% sucrose solution. Again, place the tube in the boiling water bath for 2 minutes, remove and cool.

Record the color put 2ml of the 5% sucrose solution to a test tube. This time add several drops of hydrochloric acid. Place the tube in the boiling water bath for 2 minutes. Remove and immediately add 3ml of benedict’s solution return it to the water bath for an addition 2 minutes. Remove and record the color put 3ml of benedict’s solution in a test tube. Add 2ml of milk. Again, place this into the boiling water bath for 2 minutes, remove and cool. Record the color. Again put 2ml of milk to a test tube. This time add several drops of hydrochloric acid.

Place the tube in the boiling water bath for 2 minutes. Remove and immediately add 3ml of benedict’s solution. Return it to the water bath for an additional 2 minutes. Remove and record the color. Put 3ml of benedicts solution in a test tube. Add 2ml of starch solution. Place the tube once again into the boiling water bath for 2 minutes, remove and cool. Record the color. Again, put 2ml of starch into a test tube. This time add several drops of hydrochloric acid. Place the tube in the boiling water bath for 2 minutes. Remove and immediately add 3ml of benedicts solution return it to the water bath for an additional 2 minutes.

Remove and record the color. Starch test: if a poly saccharide such as starch is present in a solution and iodine is added, the iodine ion will lodge itself in the polysaccharide chain and give it black-blue color. If iodine is added to a solution turn black-blue then starch is present. If the solution remains the color of iodine, reddish-orange, there is no starch present. Procedure: place a few drops of the starch solution into one well of a porcelain spot plate. Place a few drops of water into another well of the same plate. Add several drops of the iodine solution to both wells.

Record the color of each.

Data

When testing protein, the egg albumin solution turned dark violet when biuret solution was added, biuret’s solution was concentrated at the bottom. When testing gelatin for protein biuret’s solution turned the solution dark violet, with biuret’s solution concentrated at the bottom, and faded to completely clear. 5 drops and 4 drops were added to each test respectively. When performing the lipid test, a drop of oil left a large dark stain, water didn’t not leave a stain yet it left the paper warped, and milk left a faint stain and a glossy residue on top.

When testing for lipids with sudan IV the oil stayed on top of the water and the sudan IV distributed evenly throughout the oil. When milk was tested, water mixed evenly with the milk, but the sudan IV only mixed into the very top portion of the mixture. When testing carbohydrates the 5% glucose solution changed to a cloudy red color. The 5% sucrose solution did not change color at all, and the sucrose Hcl changed to a greenish brown color. When milk was tested the solution changed to a yellow green color, it also looked chunky. When milk and hcl was tested it changed to a cloudy blue with chunks of white on top. he starch solution did not change color when the benedict’s solution was added, and Hcl did not alter the results in the next test.

Analysis and Conclusions

Throughout the chemical aspects of life lab i have learned a variety of things including testing methods, what reagents are, and some general information about HCL and the contents of various substances. When testing proteins i have discovered the both egg albumin and gelatin both contain protein. During testing for lipids, i’ve learned that milk contains lipids, although a faint amount there are some present. Oil and Milk both contain lipids. Oil as expected, and milk as expected.

When testing For lipids using Sudan IV the oil sat ontop of the water and the sudan IV only mixed with it, but surprises came in the next test when water and milk mixed evenly, but Sudan IV only stayed to the top portion of the mixture. Testing for reducing sugars has led me to believe the HCL breaks down sugars to a simpler form, as it altered results for sucrose and milk. Glucose was already a reducing sugar as i found out after testing and sucrose was not, but after adding HCL to sucrose, the results dramatically changed so much so as from going to light blue in the first test to greenish brown in the second sucrose test.

Milk seemed to have traces of reducing sugars but results were unclear, so HCL was added and the solution went from chunky yellow in the first milk test, to a chunky cloudy blue in the second test. Starch was found without any reducing sugars, if HCL was present or not. The solution was opaque blue because of benedict’s solution. While testing carbohydrates with test tubes and fancy heating and a bunch of chemicals is fun and all, it can just as simply be done with iodine using a porcelain spot plate.

Iodine turns a dark color when in the presence of carbohydrates such as it did when in a starch solution and it was good old diluted brown-orange in water.

Materials

Dilute egg albumin solution gelatin distilled water whole milk oil 5% sucrose 5% glucose starch solution glass stirrers biuret solution sudan IV benedict’s solution hydrochloric acid iodine pan of soapy water test tube clamps test tube brushes paper towels test tubes medicine droppers porcelain spot plate safety goggles test tube racks graduated cylnders beakers hot plate brown paper bag squares