Please answer the Hands On Lab questions below (there are 5). I have provided th
ID: 280699 • Letter: P
Question
Please answer the Hands On Lab questions below (there are 5). I have provided the results from my lab experiments.
Exercise 1: Starch and Sugar
Data Table 1. Benedict’s Reagent Data.
Sample
Initial Color
Final Color
Reducing Sugar Present in Sample? Y or N
dH2O
Clear
Blue
N
Albumin
Yellow
Blue
N
Unknown
Clear
Blue
N
Milk
White
Yellow
Y
Glucose
Clear
Orange
Y
Data Table 2. Lugol’s Iodine Data.
Sample
Initial Color
Final Color
Starch Present in Sample? Y or N
dH2O
Clear
Amber
N
Albumin
Clear
Amber
N
Unknown
Clear
Amber
N
Milk
White
Beige
N
Starch
Cloudy
Dark Blue
Y
Raw Potato
Beige
Black
Y
Questions
A) In each of the two tests (starch and sugar) a positive and negative control was used. What was the positive control in each of the tests and what was the negative control. Explain your answers.
B) Did the Benedict’s test for reducing sugars net a positive or negative result for milk? Research the sugar content of milk and the definition of a reducing sugar to explain if your result is what you would expect.
C) Based on your results, is sugar and/or starch present in your Unknown? Use your results to explain your answer.
Exercise 2: Proteins and Lipids
Data Table 3. Biuret’s Reagent Data.
Sample
Initial Color
Intermediate Color
Final Color
Protein Present in Sample? Y or N
dH2O
Clear
Blue (Light)
Blue (Light)
N
Albumin
Yellow
Purple
Purple
Y
Unknown
Clear
Purple
Purple
Y
Milk
White
Purple
Purple (light)
Y
Data Table 4. Lipid Observations.
Sample
Sample Observations
Lipid Present in Sample? Y or N
Distilled water
The distilled water did not take the Sudan III red coloring outside of the pencil line.
N
Albumin
Albumin did not take the Sudan III red coloring outside of the pencil line.
N
Unknown
The unknown did not take the Sudan III red coloring outside of the pencil line.
N
Milk
The milk did take a very small amount of the Sudan III red coloring outside of the pencil line.
Y
Vegetable oil
The vegetable oil easily made it outside the pencil line with the Sudan III red coloring.
Y
Questions
A) Review the Data Tables in Exercises 1 and 2. Compare the results of the Unknown for all tests to the results for the various known samples to determine the identity of the Unknown. Explain the identity of the Unknown using your experiment results in the exercises to help explain and support your answer.
B) Eggs are known to contain cholesterol which is a lipid. Did your experiment results indicate a presence of lipids in the albumin solution? Think about this result and where cholesterol is present in eggs to explain how your results support or reject cholesterol in eggs. How could you test this? Explain the experiment that you would perform to test this.
Sample
Initial Color
Final Color
Reducing Sugar Present in Sample? Y or N
dH2O
Clear
Blue
N
Albumin
Yellow
Blue
N
Unknown
Clear
Blue
N
Milk
White
Yellow
Y
Glucose
Clear
Orange
Y
Explanation / Answer
1. A) In benedicts test- positive control- Glucose plus Benedicts reagent
- Negative control- Water and Bendicts agent .
In Lugols- positive control- Egg albumin plus Biurets agent
-Negative control- water plus Biurets agent.
B) The benedicts test is positive for milk as it contains Lactose .
C)The unknown solution changed the colour from clear to blue , which confirms the presence of reducing sugar.
Test for lipids and proteins
A)The colour of the unknown solution changed to purple , which confirms the presence of proteins.On the other hand , the unknown solution did not take up the Sudan III , which confirms that there is no lipids present.
B) Egg contains cholesterol, but in the yolk, not the albumin. The albumin of egg is rich in proteins but doesnt have any fats.