Transcript Chemical Aspects of Life Lab 3

CHEMICAL ASPECTS OF LIFE
LAB 4
Pre-lab Discussion
LAB REPORT
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…

TITLE PAGE
Chemical Aspects of Life
Your Name
Your Partner’s Name
Due Date
Period
HYPOTHESIS
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.

MATERIALS

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.
PROCEDURES
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.

DATA
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.

ANALYSIS AND CONCLUSIONS
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.

GRADING RUBRIC
Title
 Hypothesis
 Materials
 Procedure
 Data
 Conclusion
 Total

=2
= 16 (8pts. for both partners if only one hypothesis page is turned in)
=5
= 10
= 16
= 16 (8pts. for both partners if only one conclusion page is turned in)
= 65
BACKGROUND

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:
SUBSTANCE
Protein
TEST
Biurets
COLOR
GROUP
Violet
Amino group
Red-brown,
orange,
green
carbonyl or
ketone or
aldehyde
Benedict’s
and HCL
Red-brown,
orange,
green
Carbonyl or
ketone or
aldehyde
Sudan IV
Distribution of Insoluable in
dye
water
(blue solution)
Simple or
Benedict’s
reducing sugar (blue solution)
(monosaccharides)
Non-reducing
sugar
(Di/Poly saccharides)
Lipids
(Dark red solution)
Grease spot
THE “CARBS”
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

IODINE 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
HYPOTHESIS PAGE(S)
Karyn’s (Your Name) Hypotheses:
 Protein Tests:

1.
2.

If Biuret solution is added to egg albumin, then it
will turn from blue to violet.
If Biuret solution is added to gelatin, then….
Lipid Tests: Grease Spot:
1.
2.
3.
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.
If a drop of water is placed on a piece of brown
paper bag, then…
If a drop of milk is placed on a piece of brown paper
bag, then…

Lipid Tests: Sudan IV:
1.
2.
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.
If Sudan IV is dropped into a water and milk
mixture, then…

Carbohydrate Tests: Benedict’s :
1.
2.
3.
4.
5.
6.
7.

If Benedict’s solution is added to a 5% Glucose solution,
then the Benedict’s will change from blue to reddishbrown.
If Benedict’s solution is added to a 5% Sucrose solution,
then….
If Benedict’s solution is added to a 5% Sucrose solution
plus HCl, then…
If Benedict’s solution is added to milk, then…
If Benedict’s solution is added to milk and HCl, then…
If Benedict’s solution is added to starch, then…
If Benedict’s solution is added to starch and HCl, then…
Carbohydrate Tests: Starch:
1.
2.
If iodine is added to a starch solution, then the solution
will turn from reddish-orange to blue-black.
If iodine is added to water, then….