IMPmlceslab

IMPmlceslab - B IOLOGY 3A Worksheet LAB 2: B iologically...

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BIOLOGY 3A Worksheet Name: Kathleen, Karina, Layla LAB 2: Biologically Important Molecules Lab Section: Bio 3a Morning Lab Benedict’s Test for Reducing Sugars : 1. Examine Figure 2. Which groups of a glucose molecule are involved in forming a polysaccharide? Write the groups. Two hydroxyl groups. 2. In the Benedict’s test, which of the solutions is a positive control? Which is a negative control? Positive- onion juice, potato juice, glucose Negative- sucrose, water 3. Which is a reducing sugar, sucrose or glucose? Reducing sugar - glucose 4. Which contains more reducing sugars, potato juice or onion juice? Onion has more reducing sugars because of the amber color 5. Is there a difference between the storage of sugars in onions and potatoes? Yes, the darker brown of the onion juice means there are more reducing sugars compared to the orange/yellow color of the potato juice The iodine test for starch : 6. In the Iodine test, which of the solutions is a positive control? Which is a negative control? The positive- potato juice, starch Negative- onion juice, sucrose, glucose, water, fructose 7. Which colors more intensely, onion juice or potato juice? Potato juice colors more intensely 8. What can you infer about the storage of carbohydrates in onions? in potatoes? Potatoes store more carbohydrates 9. Table 1. Color reactions for Benedict’s and Iodine tests for solutions provided in laboratory Tube Solution Benedict's Color Reaction Iodine Color Reaction 1 10 drops onion juice (+) brown/orange (-) amber 2 10 drops potato juice (+) orange/yellow (+) blue 3 10 drops sucrose solution (-) blue (-) amber 4 10 drops glucose solution (+) red/orange (-) amber 5 10 drops distilled water (-) blue (-) amber 6 10 drops fructose solution (+) rust red (+) blue Bio 3A Lab: Biologically Important Molecules Worksheet Page 1 of 5
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7 10 drops starch solution
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This note was uploaded on 02/28/2012 for the course BIO 3A taught by Professor Huntley during the Spring '10 term at Saddleback.

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IMPmlceslab - B IOLOGY 3A Worksheet LAB 2: B iologically...

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