Pre-lab: Identifying Carbohydrates

4. There are other types of reagents used to determine what type of biomolecule a substance is. For example, copper ions present in Benedict’s reagent reacts with the free end of any reducing sugars, such as glucose, when heated. Originally blue in color, these copper ions are reduced by the sugar, and produce an orange-red colored precipitate. Alternatively, iodine-potassium iodide (IKI) may also be used when working with starch. IKI contains special tri-iodine ions which interact with the coiled structure of a starch

1. Fill in the table below with the results from the monosaccharide test experiment, and your conclusions based on those results.

The purpose of this lab was to test different substances using various procedures to see what biomolecules were present and ultimately find out what restaurant Anna Lyza had eaten at before she died. For the first control test, we used vegetable oil to test for lipids. So, if the solution does not contain lipids, it does not become translucent when placed onto a paper bag square and held up to a light. So, it is a negative result. However, in the presence of lipids, the solution will become translucent when placed onto a paper bag square and held up to a light. Therefore in this case, the result is positive. On the other hand, we used albumin egg to test for proteins in another control test. If the solution does not contain proteins, it will not experience any color change and so it is a negative result. When there are proteins existing in the solution, it will turn bluish/purplish and for this reason it is a positive result. Furthermore in the third control test, we used dextrose to test for simple carbohydrates such as glucose. If the solution does not contain simple carbohydrates, it will not undergo any color change and will remain a blue color. So, it is a negative result in this circumstance. If there are simple carbohydrates present in the solution, the solution will turn reddish and so the result is positive. For the last control test, we used starch solution to test

The null hypothesis will be that the test tubes with an increase in temperature, pH values, enzyme concentrations, and substrate concentration will have a very small color change or no color change at all. The alternate hypothesis is that the test tubes containing an increase in temperature, pH values, enzyme concentrations, and substrate concentration will all have an intense color change; the more the change, the more intense the color change will be.

The iodine test is used to identify glycogen and starch. These polysaccharides combine with iodine to

A cell, the building block of all living organisms, is composed of four fundamental biomolecules: proteins, carbohydrates, sugars and lipids. Proteins provide a vast amount of functions cells such as they serve as enzymes, provide structural support to cells, and act as antibodies. Reagents are used to spark a chemical reaction. The reagent used to detect protein traces in a substance is Biuret’s. Biuret’s will turn purple if proteins are present and blue if they are none. Biuret’s copper particles, have a charge of +2, are diminished to a charge of +1 when peptide bonds, which are in proteins, are present, creating the color change. Polysaccharides, which are carbohydrates, are most notably known to provide energy to the body, but they also help in breaking down fatty acids. Iodine is the reagent used to determine whether a substance has starch in it. The iodine/starch complex has energy levels that are only for retaining unmistakable light, giving the complex its extraordinarily dark black-blue shade. If there is no starch found, iodine will remain its natural yellowish-brownish color, but if starch is present, iodine will turn blue-black. Monosaccharides, which are sugars, like polysaccharides, provide the body with energy. To detect monosaccharides, the reagent, Benedict’s, is used. Benedict’s reagent is added to a test tube, then it is placed in

Dairy should not be a primary food group on the dietary guidelines set by the government because of its many negative effects on human health (given that people care about their health and the health of those around them). Dairy and other animal products are the only food sources which contain cholesterol. Arguments have been made saying that humans need to consume cholesterol in order to have a healthy balance of fats; these arguments fail to acknowledge that our bodies naturally produce all the cholesterol that it needs. And many studies have been conducted to support the theory that consumption of dietary cholesterol overloads arteries and can cause heart disease, artery disease, as well as sudden heart attacks. The Department of Community Health and Preventative Medicine at Northwestern University Medical School worked to interpret an international study based on data from the Food and Agriculture Organization and the World Health Organization. The overall conclusion was that “…dietary cholesterol levels are consistently related to CHD (coronary heart disease) mortality rates” (Stamler). A study conducted by Lena Ohlsson at the Laboratory of Gastroenterology and Nutrition within the prestigious Lund University in Sweden also linked dietary cholesterol and milk fat with artery disease and other metabolic disorders. In short, the abstract of her lab report said that low-density lipoprotein (LDL)—“bad” cholesterol—was found to be directly associated with coronary artery

2. Four unknown samples were included in the lab kit: flax seed meal, potato starch, egg whites, and dried milk. Using the results of the biochemical testing, determine which number corresponds to the correct unknown. (8 points)

b) Benedict test the solution color will change from blue to pink/orange red, indicating simple sugars are present. Lugols test the solution color will change from yellowish brown to dark purple, indicating starch and polysaccharides are present. Sudan iV test the lipid content will turn into red, indicating lipids are

Analysis: In this experiment, every substance tested positive for at least 1 organic compound. Corn oil tested positive for lipids. Honey and oats tested positive for starch. Honey, apple juice, and unknown 1 tested positive for sugar. Egg white, gelatin, and unknown 2 all tested positive for proteins. So, not a single substance didn't test positive for at least 1 organic compound. All the indicators used in this experiment change color when in the presence of a compound; therefore, they chemically react with the compound. No errors were made during this experiment

**Glucose and Starch graphs are separated because of the significantly different concentrations of the two which obscures the graphs when plotted together

Triglyceride concentrations in the liver are much higher than the heart and kidney. The differences between triglyceride and glycerol concentrations were triglyceride includes the free glycerol plus the glycerol. Pure glycerol concentrations were not determined because of reagent availability. The triglyceride concentrations were assumed to be proportional to glycerol concentrations. (Figure 2)

What happens if you eat too few carbohydrates? What happens if you eat too few lipids?

The start of the experiment consisted of filling up four beakers with de-ionized water to 150 ml. After the beakers were filled to the appropriate amounts they were then labeled with the

During the Benedict's test, the contents of tube B did not change, indicating the absence of sugar in that particular substance. However, the contents of tube A did change orange indicating the presence of sugar in that substance. During the Lugol's test, the content of tube A did not change dark purple indicating the absence of starch in that substance However, the content of tube B changed to dark purple