Biology 1510 lab 1 exam

Biology 1510 lab 1 exam - Pictu re 2 Biology 1510: Lab Exam...

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Unformatted text preview: Pictu re 2 Biology 1510: Lab Exam I Name: _______________________________ Time Limit: 75 minutes Instructions: During this examination, you may not consult notes, cell phones, books, or fellow students. Write as legibly as you can. Lab instructor cannot answer any questions during the test; if the instructions are unclear, just do the best you can. Prior to the test, seating arrangements will be determined by lab instructor. Answers will be posted within 24 on instructors website. Scores will be graded on a curve. Lipids [13 pts] 1. You have been given a liquid containing fatty acids. You perform TLC (thin layer chromatography) on it with the results shown on the left. a. How many individual fatty acids are present in this sample? [1 pt] 3 fatty acids b. What is the Rf value of each of the fatty acids in this sample? [2 pts] a = 4/10 = 0.4 b= 7/10 = 0.7 c= 9/10 = 0.9 c. All things being equal, which fatty acid is least soluble in this TLC system? [1 pt] sample a (OR) the one that traveled the least (OR) the one with Rf = 0.4 d. Please identify, with arrows and labels, the origin [1 pt] and the solvent front [1 pt] of this chromatogram? X at bottom; thick black line on top 2. My friend Joe gave me 2g of a substance, which he claims is a lipid. He also gave me a plain peace of paper, a beaker of water, 2 g of table sugar and nothing else. Describe in detail 4 simple tests [1 pt each] which would allow me to decide whether the substance is indeed a lipid. In each of these tests, what would the control be? 1. Greasy. Check sugarit not greasy. 2. Translucent when raised against light. Control: sugar isnt. 3. Water insoluble. Spread a bit of the fat on paper, and a bit of sugar some distance away. Drop of water on both. 4. Lipids float on water; sugar sinks or dissolves 3. Circle one (a total of 3 circles) in each underlined group: A reaction joining a triglyceride to 1 /2 /3 / 4 / 5 /6 fatty acids / Benedict / monosaccharide / DNA releases / takes up / evaporates / liquefy water molecules. [1 pt] 3 / fatty acids / releases 4. Fill in the blanks: Saturated lipids contain all the _________ atoms they can possibly have [1 pt] Hydrogen 5. T/F: Molecule per molecule, carbohydrates store less energy than lipids True / False [1 pt] True Carbohydrates / Nature of Science [17 pts] 1. The carbohydrates lab involved three tests--Benedict for reducing sugars, Barfoed for monosaccharides, Iodine for some polysaccharides. Use the following chart to answer questions a through c . Benedict Test Barfoed Test Iodine Test Sample A (+) (+) (-) Sample B (-) (-) (-) Sample C (-) (-) blue-black a. Is Sample A glucose, maltose, sucrose, glycogen or amylose (from starch)? [1 pt] reducing, monosaccharide, non-polysaccharide = glucose b. Is Sample B glucose, maltose, sucrose, glycogen or amylose (from starch)? [1 pt] non-reducing, non-monosaccharide, non- polysaccharide = sucrose c. Is Sample C glucose, maltose, sucrose, glycogen or amylose (from starch)? [1 pt] non-reducing, non-monosaccharide, branched...
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Biology 1510 lab 1 exam - Pictu re 2 Biology 1510: Lab Exam...

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