Name of Student: Alisa Rafiudeen Name of Course: Bio 202 L (Introduction to
Biology 2)
Instructor: Dr. Rollins
Title: Biochemical Identification of Major Functional Groups by Qualitative Analysis
Date lab was done: 13th September, 2011
Date to be submitted: 15th November, 2011
Hypothesis Testing:
1) Water will give a negative test to the Biochemical analysis done.
2) The analysis would be done on one or two substances which contains the molecules being
tested for (to demonstrate positive results).
3) To determine if other substances with unknown composition will give a positive or negative
result.
Abstract:
Oxalic acid was used to test for calcium ions and a positive result is the formation of a precipitate
in CaCl2 solution and cloudy in the yogurt sample. Silver Nitrate was used to test for chlorine
ions and a positive result is the formation of a silver chloride precipitate in the NaCl. The test for
reducing sugars was positive for glucose, lactose and hydrolyzed sucrose when Benedict’s
solution was added followed by heat. The iodine test gave a positive purple coloration for starch.
The Sudan test formed a cherry red solution when it was mixed with the lipid, triglyceride. The
Ninhydrin test gave a positive blue coloration for amino acids and hydrolyzed proteins. The test
for peptides was done via the Biuret reagent which became light violet in color especially in the
protein sample. Finally, the diphenylamine test was used to predict if a substance had nucleic
acid present and when DNA was present it turned dark brown while if RNA was present, it
turned light green. In all the cases, water was proved to be the negative control.
Introduction:
Organic molecules consist of carbon, hydrogen and oxygen and these make up the
carbohydrates, proteins, lipids and nucleic acids. These are macromolecules that are made from
smaller units known as monomers. The bonds between the smaller units are formed by
dehydration reaction where a molecule of water is removed. The macromolecules are broken by
hydration or addition of water.
Biochemical identification of qualitative analysis is specifically testing for particular functional
groups within a molecule. In this report, the test will be on minerals (calcium and chloride ions),
nucleic acids, reducing sugars, lipids and polysaccharides. These experiments were all done in
vitro (meaning in a glass tube).
In this experiment, there are controls. A control group in an experiment is a group that serves as a
standard of comparison with another group or to which it is identical except for one factor. The
positive control is where the phenomenon is expected. For example in the iodine test, the starch
is the positive control because it is expected to turn blue. The negative control is a way to test a
theory to make sure there is no effect because it is a solvent that does not reach in the test. In this
case it was distilled water and it should test negative for all the tests performed within this
experiment.
A mineral can be defined as a naturally occurring organic molecule. Ca2+ can be tested by using
oxalic acid. When calcium is present it readily forms a Calcium oxalate precipitate. Cl - can be
This study source was downloaded by 100000864885202 from CourseHero.com on 04-17-2023 07:11:56 GMT -05:00
https://www.coursehero.com/file/7357402/bio-202finallab/
, tested using silver nitrate and when present it would readily form silver chloride precipitate. The
following reaction occurs:
AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)
A reducing sugar is a carbohydrate that
functions as a
reducing agent due to the free aldehyde or ketone functional group within its structure. By
mixing the sugar solution with the Benedict's solution and adding heat, an oxidation-reduction
reaction will occur. The sugar will oxidize, gaining an oxygen, and the Benedict's reagent will
reduce, losing an oxygen (the sugar is oxidized by the Cu(II) ion and it thus reduces the Cu(II)
ion to Cu(I)). If the resulting solution is red orange, it tests positive, a change to green indicates a
smaller amount of reducing sugar, and if it remains blue, it tests negative. However, if a
polysaccharide is hydrolyzed, the C=O group can become reactive.
Sugar + copper II ion aldehyde + copper I ion
A starch can be defined as a naturally abundant nutrient carbohydrate with a formula of
(C6H10O5)n. The iodine test is used to distinguish starch from monosaccharide, disaccharides, and
other polysaccharides. It has a unique coiled geometric configuration and this makes it react with
iodine to produce a blue-black color and tests positive when it is mixed with starch.
A lipid consists of glycerol and fatty acids "tails". Their tails contains long chains of carbon and
hydrogen which makes them non-polar. They may be saturated (have pure single bonds) or
unsaturated (contains double bonds). The Sudan test is used to test for lipids. The sudan dye is
hydrophobic in nature and only lipids can be dissolved in them to give a cherry red solution. If
the test is negative, it form crystals and give dark red specks.
An amino acid is an organic compound
containing an
amino group
(NH2), a carboxylic acid group (COOH),
and various side groups. Ninhydrin (1,2,3-
Indantrione monohydrate, or triketohydrindene hydrate) is often used to detect -amino acids and
also free amino and carboxylic acid groups on the amino acids. After it is mixed in, it is heated
for a few minutes and a blue color develops. Ninhydrin degrades amino acids into aldehydes,
ammonia, and CO2 through a series of reactions; the net result is ninhydrin in a partially reduced
form hydrindantin (reaction is showed below):
A peptide is a short polymer of amino acid monomers that is linked by a peptide bond (-
C(=O)NH-). The Biuret test is used to detect the presence of these bonds. If present, a copper (II)
ion forms a violet-colored complex in an alkaline solution. If it is absent, it remains the color of
the reagent (light blue).
A nucleic acid is composed of building blocks called nucleotides. This is made of a sugar
molecule, a phosphate molecule and a nitrogenous base. In DNA the sugar is a deoxyribose and
the nitrogenous bases are adenine, guanine, cytosine and thymine. In RNA the sugar is a ribose
and the bases are adenine, guanine, cytosine and uracil. Nucleic acids carry the genetic
information within cells. A diphenylamine test is used to detect its presence based on the sugar
This study source was downloaded by 100000864885202 from CourseHero.com on 04-17-2023 07:11:56 GMT -05:00
https://www.coursehero.com/file/7357402/bio-202finallab/
Biology 2)
Instructor: Dr. Rollins
Title: Biochemical Identification of Major Functional Groups by Qualitative Analysis
Date lab was done: 13th September, 2011
Date to be submitted: 15th November, 2011
Hypothesis Testing:
1) Water will give a negative test to the Biochemical analysis done.
2) The analysis would be done on one or two substances which contains the molecules being
tested for (to demonstrate positive results).
3) To determine if other substances with unknown composition will give a positive or negative
result.
Abstract:
Oxalic acid was used to test for calcium ions and a positive result is the formation of a precipitate
in CaCl2 solution and cloudy in the yogurt sample. Silver Nitrate was used to test for chlorine
ions and a positive result is the formation of a silver chloride precipitate in the NaCl. The test for
reducing sugars was positive for glucose, lactose and hydrolyzed sucrose when Benedict’s
solution was added followed by heat. The iodine test gave a positive purple coloration for starch.
The Sudan test formed a cherry red solution when it was mixed with the lipid, triglyceride. The
Ninhydrin test gave a positive blue coloration for amino acids and hydrolyzed proteins. The test
for peptides was done via the Biuret reagent which became light violet in color especially in the
protein sample. Finally, the diphenylamine test was used to predict if a substance had nucleic
acid present and when DNA was present it turned dark brown while if RNA was present, it
turned light green. In all the cases, water was proved to be the negative control.
Introduction:
Organic molecules consist of carbon, hydrogen and oxygen and these make up the
carbohydrates, proteins, lipids and nucleic acids. These are macromolecules that are made from
smaller units known as monomers. The bonds between the smaller units are formed by
dehydration reaction where a molecule of water is removed. The macromolecules are broken by
hydration or addition of water.
Biochemical identification of qualitative analysis is specifically testing for particular functional
groups within a molecule. In this report, the test will be on minerals (calcium and chloride ions),
nucleic acids, reducing sugars, lipids and polysaccharides. These experiments were all done in
vitro (meaning in a glass tube).
In this experiment, there are controls. A control group in an experiment is a group that serves as a
standard of comparison with another group or to which it is identical except for one factor. The
positive control is where the phenomenon is expected. For example in the iodine test, the starch
is the positive control because it is expected to turn blue. The negative control is a way to test a
theory to make sure there is no effect because it is a solvent that does not reach in the test. In this
case it was distilled water and it should test negative for all the tests performed within this
experiment.
A mineral can be defined as a naturally occurring organic molecule. Ca2+ can be tested by using
oxalic acid. When calcium is present it readily forms a Calcium oxalate precipitate. Cl - can be
This study source was downloaded by 100000864885202 from CourseHero.com on 04-17-2023 07:11:56 GMT -05:00
https://www.coursehero.com/file/7357402/bio-202finallab/
, tested using silver nitrate and when present it would readily form silver chloride precipitate. The
following reaction occurs:
AgNO3(aq) + NaCl(aq) AgCl(s) + NaNO3(aq)
A reducing sugar is a carbohydrate that
functions as a
reducing agent due to the free aldehyde or ketone functional group within its structure. By
mixing the sugar solution with the Benedict's solution and adding heat, an oxidation-reduction
reaction will occur. The sugar will oxidize, gaining an oxygen, and the Benedict's reagent will
reduce, losing an oxygen (the sugar is oxidized by the Cu(II) ion and it thus reduces the Cu(II)
ion to Cu(I)). If the resulting solution is red orange, it tests positive, a change to green indicates a
smaller amount of reducing sugar, and if it remains blue, it tests negative. However, if a
polysaccharide is hydrolyzed, the C=O group can become reactive.
Sugar + copper II ion aldehyde + copper I ion
A starch can be defined as a naturally abundant nutrient carbohydrate with a formula of
(C6H10O5)n. The iodine test is used to distinguish starch from monosaccharide, disaccharides, and
other polysaccharides. It has a unique coiled geometric configuration and this makes it react with
iodine to produce a blue-black color and tests positive when it is mixed with starch.
A lipid consists of glycerol and fatty acids "tails". Their tails contains long chains of carbon and
hydrogen which makes them non-polar. They may be saturated (have pure single bonds) or
unsaturated (contains double bonds). The Sudan test is used to test for lipids. The sudan dye is
hydrophobic in nature and only lipids can be dissolved in them to give a cherry red solution. If
the test is negative, it form crystals and give dark red specks.
An amino acid is an organic compound
containing an
amino group
(NH2), a carboxylic acid group (COOH),
and various side groups. Ninhydrin (1,2,3-
Indantrione monohydrate, or triketohydrindene hydrate) is often used to detect -amino acids and
also free amino and carboxylic acid groups on the amino acids. After it is mixed in, it is heated
for a few minutes and a blue color develops. Ninhydrin degrades amino acids into aldehydes,
ammonia, and CO2 through a series of reactions; the net result is ninhydrin in a partially reduced
form hydrindantin (reaction is showed below):
A peptide is a short polymer of amino acid monomers that is linked by a peptide bond (-
C(=O)NH-). The Biuret test is used to detect the presence of these bonds. If present, a copper (II)
ion forms a violet-colored complex in an alkaline solution. If it is absent, it remains the color of
the reagent (light blue).
A nucleic acid is composed of building blocks called nucleotides. This is made of a sugar
molecule, a phosphate molecule and a nitrogenous base. In DNA the sugar is a deoxyribose and
the nitrogenous bases are adenine, guanine, cytosine and thymine. In RNA the sugar is a ribose
and the bases are adenine, guanine, cytosine and uracil. Nucleic acids carry the genetic
information within cells. A diphenylamine test is used to detect its presence based on the sugar
This study source was downloaded by 100000864885202 from CourseHero.com on 04-17-2023 07:11:56 GMT -05:00
https://www.coursehero.com/file/7357402/bio-202finallab/
