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Bell Work List the 4 major macromolecules and the monomers for each
Carbohydrates = monosaccharides Proteins = amino acids Lipids = fatty acids Nucleic Acids = nucleotides
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IDENTIFYING MACROMOLECULES IN Nutrients LAB
Mrs. Stewart Honors Biology
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Lab Objective Identify the presence of major nutrients such as simple carbohydrates (glucose), complex carbohydrates (starch), protein and fat in common foods.
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In this lab, with the use of indicators as chemical detection tools, you will analyze a variety of foods for the presence of macromolecule nutrients. Detection is based upon observing a chemical change that takes place most often a change in color.
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What is an indicator? Indicators are chemical compounds used to detect the presence of other compounds.
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Test for Simple Carbohydrates Benedict’s solution
Benedict's solution is a chemical indicator for simple sugars such as glucose: C6H12O6. Negative: Aqua blue Positive: Red/ orange/ yellow/ green
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Benedict’s Test The intensity of the color change is related to the concentration of simple sugars present The color change is a rainbow spectrum: Red (very positive) Orange Yellow Green Blue (Negative)
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Test for Simple Carbohydrates Benedict’s solution
Unlike some other indicators, Benedict’s solution does not work at room temperature - it must be heated first.
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Why didn’t the test tube containing starch change colors?
Question Why didn’t the test tube containing starch change colors?
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Test for Complex Carbohydrates Iodine Solution
Detects complex carbohydrates (polysaccharides) Iodine solution color change = blue to black
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Test for Complex Carbohydrates Iodine solution
Iodine solution is an indicator for a molecule called starch. Starch is a huge molecule made up of hundreds of simple sugar molecules (such as glucose) connected to each other.
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Test for Protein (amino acids) Biuret solution
Biuret solution dark violet blue to pinkish purple
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Test for Fats (lipids) Sudan III
If lipids are present the Sudan III will stain them reddish-orange (positive test).
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Green, yellow, orange, brick red
INDICATOR MACRO-MOLECULE NEGATIVE TEST POSITIVE TEST Benedict’s solution simple carbohydrate blue Green, yellow, orange, brick red Iodine solution complex carbohydrate dark red black Biuret solution protein violet, black Sudan IV lipid reddish- orange
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It’s up to you to save us! New type of zombie emerges
They thrive by feeding on simple sugars Complex carbs & proteins are deadly to them What will be the best food to combat this threat? Milk, yogurt or oatmeal?
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Test Results Milk (regular cow’s milk – whole) Test Color
Benedict’s Solution Orange Lugol’s Iodine Reddish/brown Biuret’s Solution Purple Sudan III Red throughout
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Test Results Yogurt (regular, fat-free) Test Color Benedict’s Solution
Red Lugol’s Iodine Reddish-brown at bottom Biuret’s Solution Purple Sudan III Red layer at top only
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Test Results Oatmeal Test Color Benedict’s Solution Blue
Lugol’s Iodine Dark blue/black Biuret’s Solution Purple Sudan III Red layer on top only
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