Identification of Macromolecules Essay

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Pages: 9

Macromolecule Lab

Damanjit Multani
Abira Sivarajan
Section 009
Matt Malwana
September 26th, 2013Introduction

Macromolecules are molecules such as protein, nucleic acid, or polysaccharide, with a high relative molar mass. There are three major types of macromolecules, which are carbohydrates, nucleic acid and proteins. Carbohydrates are sugars and related compounds with the general formula of CH2O. (Alberts et al.,) A nucleic acid is a DNA, which consists of a chain of nucleotides joined together by phosphodiester bonds (Alberts et al.,2010). Lastly, each protein is composed of one or more liner chains of amino acids linked together by peptide bonds. (Alberts et al.,2010)
The iodine solution is to determine the difference between starch and glycogen form other monosaccharaides and polysaccharides. The iodine solution creates a blue-black color in the presence of starch, and when reacted with glycogen it gives a brown-blue color (Last, 2004). Other monosaccharaides and polysaccharides yield no color, as they do not have any presence of starch or glycogen in them; when reacted with other solutions the color stays the same as the reagent. The storage of a simple sugar like glucose is held in both plants and animals, as that is present in polysaccharides. Although, in plants starch is used for as storage, which is composed of a large number of glucose molecules linked together by glycosidic bonds. (Alberts et al., 2010). In animals, glycogen is synthesized and stored in the liver and muscles for later use. (Charles, 2003). Amylose, which is a helical molecule where a glucose units are held together by alpha (1 to 4) linkages, this molecule is in starch which allows it to react with iodine to produce the blue color change in the solution. Whereas, amylopectin is present in glycogen for the overall structure and it forms alpha (1 to 6) linkages. (Allan et al.,2012). Benedict’s test reducing sugar is conducted specifically to test the presence of reducing sugar in a certain solution. The Benedict’s solution allow the copper ions, which are mixed with a certain solution to free the aldehyde groups on the end of the sugar chain to reduce the cupric ions to cuprous ions. Thus, combing to oxygen to form a precipitate in the solution (Alberts et al., 2010). The copper sulfate, which is present in Benedict’s solution, this allows the electrons to react to the aldehyde or ketone group of the sugar to produced a red-brown precipitate. Increasing levels of reducing sugar would be shown if the solution changed colors ranging from green, orange, red, or brown (Gurien, 2008).
The biuret test for protein is used to detect the reaction of peptides and proteins. The reagent is made of sodium hydroxide and copper sulfate, which turns the solution violent in the presence of proteins (Garcia, 2002). The violet color is a positive test for the presence of protein, the more intense the color, the greater the number of peptide bonds that are reacted with the reagent. (Last, 2008).
Materials and Methods
12 small disposable plastic beakers
Pasteur pipettes & bulbs
1 spot plate
12 Test-tubes
1 test-tube clamp
1 dropper bottle containing 1% copper sulfate
1 dropper bottle containing iodine (Lugol’s) solution
1 large beaker (600 ml) with boiling chips
1 marker
1. Obtain all the materials listed above
2. Label the small beakers #1 through #12
3. Into beaker #1 add approximately 15ml of 1% glucose solution
Into beaker #2 add approximately 15ml of 0.3 % glucose-1-phosphate
Into beaker #3 add approximately 15ml of 1% maltose solution
Into beaker #4 add approximately 15ml of honey solution
Into beaker #5 add approximately 15ml of 1% sucrose solution
Into beaker #6 add approximately 15ml of 1% lactose solution
Into beaker #7 add approximately 15ml of 1% glycogen solution
Into beaker #7 add approximately 15ml of 1% starch solution