Testing for Macromolecules Lab

Name: Sahil KumarTeacher: Mrs. SadyoraCourse: SBI4U

PurposeTo use a set of standardized procedures to test for sample sugars and starch and proteins.

Materials 10 ml Graduated cylinders 16 test tubes 400ml beaker Back well plate Baking soda Benedicts reagent Biuret reagent Distilled water Gelatin Solution Glucose solution Hot plate Lugols Solution Medicine Droppers Test tube rack Stirring rod Thermometer Wax pencil Unknown A Unknown B Unknown CObservationsPart ANameColourApproximate sugar Concentration

Baking soda solutionBlue0

Starch solutionGreen to yellow1.0 2.0

Distilled waterBlue0

GlucoseGreen to yellow1.0 2.0

Unknown AGreen to yellow1.0 2.0

Unknown BBlue0

Unknown CLight green0.5 1.5

NameColourPresence of Starch

Baking soda solutionDark BrownNo starch

Starch solutionBluish BlackStarch Found

Distilled waterDark BrownNo Starch

GlucoseDark RedNo Starch

Unknown ADark RedNo Starch

Unknown BDark RedNo Starch

Unknown CDark BlueStarch Found

Part CNameColourRelative Amount of Peptide bonds

Distilled WaterBlueNo Protein

Baking SodaPurple+++

Unknown APink+

Unknown BViolet++

Unknown CBlueNo Protein

StarchBlueNo Protein

GlucoseBlueNo Protein

Gelatine blueNo Protein

Discussion Questions: (Analyze and Evaluate)a) The dependent variables that were measured and recorded in this investigation were the change in colours of the solution, the change in colour was dependent on something being added to cause the change and in this lab it was the Benedicts reagent, Lugols solution, and Biuret reagent. The independent variables that were measured and recorded was the controlled lab (distilled water).

b) The results were as reliable as they could possibly be; also the meaning of the results was given in the textbook.

c) The baking soda having peptide bonds was surprising.

d) The test that was most difficult to conduct was Part C: Protein test, because it was hard to tell violet form purple.

e) Negative control is the variable where nothing is expected to happen and it ensures that there is nothing happening where nothing should happen.

ConclusionBased off of the results it is known that certain foods contain sugars or starch and proteins, and some do not.

Application: (Apply and Extend)f) Knowing the chemical makeup of what we eat can help humans make better choices for a healthier lifestyle, specifically as to eating as their health requires if they have a condition or disorder in which they cannot digest specific sugars or enzymes.

g) Waffles are high in carbohydrates, Ensure (a meal replacing milk beverage) is high in proteins, and Margarine or other shortenings with hydrogenated oils are high in fats. Other substances that are listed on a food label are minerals and vitamins, it is important to know about the presence of these substances because they are also needed in our body and help us to perform daily functions. It is also important to know about them as too much consumption may harm us.

h) BHA (butylated hydroxanisole) and BHT (butylated hydroxytoluene) are antioxidants and are added to edible fats and high fat containing foods; they help foods from smelling rancid or going bad. The potential effects are disastrous as they are human carcinogens and can cause cancer also BHT can cause hyperactivity in children. These are very harmful substances and we should know if they are in our foods or not.

Sources of ErrorPossible sources of error could have been minor variances in the graduated cylinders used to measure out each solution. Another error could have been damaged or faulty equipment which may have ruined the results such as dirty test tubes.

Bibliography for research question:http://chemistry.about.com/od/foodcookingchemistry/a/bha-bht-preservatives.htm