Name: Alisa
Biology 12 Unit 2 Organic Molecules Worksheet
Instructions: Please refer to the Unit 2 Assignment activity and answer in complete
sentences.
Carbohydrates:
1. What are monosaccharides and what molecules are contain in a
monosaccharide (draw a diagram)?
-Monosaccharides are single sugar molecules that include glucose, fructose, and
galactose that react with Benedicts reagent to test presents of simple sugars.
2. What colour is Benedict’s reagent? What observations (colour and changes)
were made when Benedict’s reagent was added to water?
- Benedict reagent is dark blue. When added to water, solution turned blue.
3. What observations (colour and changes) were made when Benedict’s reagent
was added to glucose solution and heated?
- The Benedict solution changed to a think orange/red color.
4. Describe the expected results and observations for a positive test for simple
sugar. Describe the expected results and observations for a negative test for
simple sugar.
- A positive test for simple sugar > Benedict reagent to turn orange/red. A negative
test > Benedict reagent goes slightly light blue.
5. Describe the expected results and observations for a positive test for complex
sugar (ie. Starch). Describe the expected results and observations for a negative
test for complex sugar. What is the indicator used for testing complex sugar?
- Negative results with added starch: Dark brown
- Positive results with added starch: Yellow
6. If hydrolysis occurred with the sucrose, what would you expect to see if you did
the Benedict’s test? Explain why.
- If hydrolysis occurred the Benedicts reagent would remain a light blue color.
7. Would you do the iodine test? Explain why or why not.
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Proteins:
8. Describe the expected results and observations for a positive test for protein.
Describe the expected results and observations for a negative test for protein.
What is the indicator used for testing protein?
- Expected positive results: Color turns from a light blue to violet. Protein reacts
with blue reagent
- Expected negative results: color will turn a dark green.
Fats:
9. Describe the expected results and observations for a positive test for fat.
Describe the expected results and observations for a negative test for fat. What
is the indicator used for testing the presence of fat?
- Expected results for positive test will change the color of fat to red. Negative test
would result in half cloudy/clear and half red.
Foods:
10. Complete the table of common food item and the presence of organic
compounds. Please indicate a positive test (presence) with a “+” and a negative
test with a “-.”
Presence of
Organic
molecules
Types of Food
Potato
Orange Juice
Nuts (almonds)
Eggs
Salmon
Milk
Simple
Sugars
Starch
Protein
Fat
+
+
+
+
-
+
+
+
+
-
+
+
+
+
-
+
+
+
-