Presentation on theme: "C HEMICAL A SPECTS OF L IFE L AB 4 Pre-lab Discussion."— Presentation transcript:
C HEMICAL A SPECTS OF L IFE L AB 4 Pre-lab Discussion
L AB R EPORT You will be expected to write a lab report for this activity. You will need to follow the guidelines provided on the handout: “How to write a Lab Report” You will complete parts of your lab report with your partner and parts of it on your own. All lab reports must be typed (double-spaced) Here is what I want turned in to me…
T ITLE P AGE Chemical Aspects of Life Your Name Your Partner’s Name Due Date Period
H YPOTHESIS You must turn in two separate hypothesis pages …one written by you and one written by your partner. They should not be identical. If you only turn in one hypothesis page, you will receive ½ credit for this part of the lab. You must write a hypothesis statement for each test you perform in this lab. Each must be in an “If…then” format. We will do part of this together in class. You will not lose credit if, after testing, you discover that your hypothesis was incorrect. Please do not change it. Just indicate in your discussion that you discovered it was wrong and explain why.
M ATERIALS A list of materials needed for this lab is provided in your lab handout. You will need to include this in your typed lab report.
P ROCEDURES The procedures for each test are also included in your lab handout. This section explains what you did for each test. This should not be a “dialogue” with lots of “fluffy words”. Keep it brief, with numbered statements or bullets.
D ATA This section will show the results of each test. Use your data chart from lab to construct your own typed chart. Include it in your report.
A NALYSIS AND C ONCLUSIONS You must turn in two “Analysis and Conclusions” pages …one from you and one from your partner. They should not be identical. In this section, you will explain your results and state if your hypothesis was correct. For example, if you saw a color change in an experiment, you must attempt to tell why you saw a color change. What was happening chemically to cause it ? You should use a lot of the vocabulary terms from this chapter in your discussion….things like monosaccharide, disaccharides, polysaccharides, amino acids, reducing sugars, solubility, etc.
G RADING R UBRIC Title = 2 Hypothesis = 16 (8pts. for both partners if only one hypothesis page is turned in) Materials = 5 Procedure = 10 Data = 16 Conclusion = 16 (8pts. for both partners if only one conclusion page is turned in) Total = 65
B ACKGROUND In this lab you will be testing for the presence of the following substances: Proteins Lipids Carbohydrates You will use various chemical indicators to test for the presence of these substances. Proteins will be tested with Biuret’s solution Lipids will be tested with Sudan IV Carbohydrates will be tested with Benedict’s solution and Iodine solution Use the following chart as a reference:
S UBSTANCE TEST COLOR GROUP ProteinBiurets (blue solution) VioletAmino group Simple or reducing sugar (monosaccharides) Benedict’s (blue solution) Red-brown, orange, green carbonyl or ketone or aldehyde Non-reducing sugar (Di/Poly saccharides) Benedict’s and HCL Red-brown, orange, green Carbonyl or ketone or aldehyde LipidsSudan IV (Dark red solution) Grease spot Distribution of dye Insoluable in water
T HE “C ARBS ” The carbohydrate test is the most confusing. You really need to understand the difference between monosaccharides (reducing sugars) and disaccharides (non-reducing sugars) Disaccharides include: Maltose – glucose + glucose Lactose – glucose + galactose Sucrose – glucose + fructose
I ODINE TEST Starch test with iodine turns blue black for positive test Water with iodine is the control Important test – will be used many times this year
H YPOTHESIS P AGE ( S ) Karyn’s (Your Name) Hypotheses: Protein Tests : 1. If Biuret solution is added to egg albumin, then it will turn from blue to violet. 2. If Biuret solution is added to gelatin, then…. Lipid Tests: Grease Spot: 1. If a drop of oil is placed on a piece of brown paper bag, then there will be a grease spot when the oil evaporates. 2. If a drop of water is placed on a piece of brown paper bag, then… 3. If a drop of milk is placed on a piece of brown paper bag, then…
Lipid Tests: Sudan IV: 1. If Sudan IV is dropped into a water and oil mixture, then the dye will remain dissolved in the oil which will be on top of the water. 2. If Sudan IV is dropped into a water and milk mixture, then…
Carbohydrate Tests: Benedict’s : 1. If Benedict’s solution is added to a 5% Glucose solution, then the Benedict’s will change from blue to reddish- brown. 2. If Benedict’s solution is added to a 5% Sucrose solution, then…. 3. If Benedict’s solution is added to a 5% Sucrose solution plus HCl, then… 4. If Benedict’s solution is added to milk, then… 5. If Benedict’s solution is added to milk and HCl, then… 6. If Benedict’s solution is added to starch, then… 7. If Benedict’s solution is added to starch and HCl, then… Carbohydrate Tests: Starch: 1. If iodine is added to a starch solution, then the solution will turn from reddish-orange to blue-black. 2. If iodine is added to water, then….