Experiment 1: CARBOHYDRATES A. Qualitative Tests and Analysis of Unknown

Obtain an unknown sample from your instructor. This is to be subjected to the following qualitative tests necessary for its identification. For standard comparison, the same tests and reactions would also be carried out on 1% solutions of glucose, sucrose, fructose, lactose, galactose and starch. Distilled water will be the negative control. Use small test tubes. Use a 250 mL beaker half-filled with water for the hot water bath. Throw all solutions in a labeled waste crock after the experiment. (Reminder: Bring cotton on the day of the experiment). 1. Osazone Test Class work!

Add 10 drops of each test solution (glucose, fructose, lactose, galactose and unknown) to 30 drops of freshly prepared phenylhydrazine reagent. Place the test tubes in boiling water bath for about 30 minutes. Record the time when crystals first appear. If no crystals appear after 30 minutes, place in an ice bath. Note the color of the crystals. Place some crystals on a glass slide and observe under the microscope. Sketch their appearance. 2. Molisch Test

Add 1 drop of Molisch reagent to 30 drops of each test solution (glucose, sucrose, fructose, lactose, galactose, starch, a piece of cotton and unknown). Incline the container and slowly pour 1 mL of concentrated H2SO4 down the side so that the acid forms a layer at the bottom. Do not shake or mix. Note the color at the junction of the two liquids.

3. Fehlings's Test

To 10 drops of each test solution (glucose, sucrose, fructose, lactose, galactose, starch and unknown), add 30 drops of Fehling's reagent (5 mL Fehling's sol'n A + 5 mL Fehling's sol'n B + 5 mL distilled H2O). Shake the mixture and immerse in boiling water for about 2-3 minutes. Record the results. 4. Barfoed's Test

Mix 30 drops of Barfoed's reagent and 20 drops of each test solution (glucose, sucrose, fructose, lactose, galactose and unknown) and place in boiling water bath. Remove the test tube once it becomes cloudy or changes color. Note the length of time for the reaction to take place. If no change happens within ten minutes, continue heating for another 5 minutes. If change in color is difficult to detect, compare the color of solution to that of the blank sample. 5. Seliwanoff's Test

To 5 drops of each test solution (glucose, sucrose, fructose, lactose, galactose and unknown), add 20 drops of Seliwanoff's reagent and place in boiling water bath for approximately 1 minute. Record the results. 6. Iodine Test

To a spot plate, add 5 drops of each test solution (glucose, sucrose, fructose, lactose, galactose, starch, a piece of cotton and unknown), add 2 drops of I2 in KI solution to each test solution. Observe.

Experiment 1: CARBOHYDRATES B. Isolation of Glycogen from Chicken Liver

Rinse the liver with water, dry with filter paper and weigh about 20 grams. Mince the

weighed liver and drop into a 250-mL beaker containing 100 mL of boiling distilled H2O. Cover and boil for about 30 minutes. At this point, the volume of the solution should have been reduced by half. Add more water if necessary. Carefully remove the beaker from the hot plate and immediately add 10% acetic acid until the solution is acidic to litmus. Filter while hot. Note the appearance of the filtrate. Perform the following tests on the filtrate:

A. Molisch Test B. Fehling's Test (make the test solution slightly alkaline before adding the reagent) *Prepare Fehlings Reagent: 2 mL Fehlings A + 2 mL Fehlings B + 2 mL dist. H2O C. Iodine Test

C. Hydrolysis of Polysaccharides

Place 2 mL of 1% starch solution in a test tube. Add 1 mL of dilute HCl. Heat in a water

bath and place 2 drops of the reaction mixture on a spot plate at 0, 5, 10, 15, 20 and 25 minutes of heating. Add 1 drop I2 in KI solution into each. Record changes in color. Cool the reaction mixture and add 1 drop of phenolphthalein. Neutralize with 10% NaOH. Perform Fehlings Test on the hydrolyzed samples.

Questions: 1. Identify the test the will help you differentiate between

a. carbohydrates and proteins b. reducing and nonreducing sugars c. ketoses and aldoses d. monossacharides from reducing dissacharides e. glucose and galactose

2. Glucose, mannose and fructose cannot be distinguished using Osazone test. Explain. 3. In the isolation of glycogen, why was the chicken liver chosen as the source of glycogen? 4. What polysaccharide is found in cotton? Discuss the differences among the structures of starch, glycogen and cellulose and correlate these with the results in III.

5. Describe the following qualitative tests for carbohydrates a. Anthrone test b. Orcinol test c. Diphenylamine test d. Mucic acid test

Experiment 1: CARBOHYDRATES Worksheet Names: Section: Group Number: Date: A. Qualitative Tests and Analysis of Unknown

Test Solution Osazone Test Molisch Test

Fehlings Test

Barfoeds Test

Seliwanoffs Test

Iodine Test

1% Glucose

1% Sucrose

1% Fructose

1% Lactose

1% Galactose

Starch

Cotton

Distilled H2O

Unknown

Unknown #: Identity: Comments:

Experiment 1: CARBOHYDRATES Worksheet B. Isolation of Glycogen from Chicken Liver Appearance of filtrate: Qualitative Tests

A. Molisch Test:

B. Fehlings Test:

C. Iodine Test: C.Hydrolysis of Polysaccharides

A. Iodine Test (Reaction Mixture) Time (Minutes) Appearance of Starch Upon Hydrolysis

0 5 10 15 20 25

B. Fehlings Test (Hydrolyzed Samples)

Starch:

Experiment 2: BUFFERS

A buffer is a solution which consists of a definite proportion of conjugate base [A-] to weak acid [HA] with a pH near the pKa of the weak acid. Since the ratio [A-]/[HA] ranges from 10-1 to 101, the two species are always present in considerable amounts. Together they resist large changes in pH by partially absorbing the H+ and OH- ions added to the system, as shown by the following equations:

H+ + A- HA (added)

OH- + HA A- + H2O (added)

Buffered solutions do change in pH but the change is much less than that which would

occur if no buffer were present. Choice of Buffer System The following criteria are used in choosing a buffer system for a particular reaction:

1. A high buffering capacity at the desired pH (i.e. choose the weak acid whose pKa is closest to the desired pH).

2. The buffer system must not affect the participants in the reaction under consideration.

3. Although a high buffering capacity is required, it is not always possible to use a relatively concentrated buffer. Consider the individual concentration of the buffer salt and acid needed to obtain a suitable buffer capacity. Concentration ranges from 0.010 to 1.0 M a. Use a high a concentration as is compatible with the features of the system. b. Too high concentration of salt frequently inhibits activity of enzymes and other physiological systems.

c. The solubility of the buffer component may also limit the concentration which can be employed.

Preparation of 0.10 M Phosphate Buffer Direction: Prepare 100.0 mL of 0.10 M phosphate buffer, pH = 7.0 from the Na salts of

monohydrogen phosphate and dihydrogen phosphate available in the laboratory. (Be sure your instructor checks your calculations before you proceed). Check the pH of the solution with a pH meter. Adjust if necessary with 1 M solutions of acid or base. Keep the buffer solution in an Erlenmeyer or Volumetric flask (labeled and covered).

Experiment 2: BUFFERS Questions: 1. Enumerate some important physiological buffers. 2. State the Henderson-Hasselbalch equation for the weak acid HA and its salt NaA. Do the same for the weak base MOH and its salt MCl.

3. What is buffer capacity? What factors determine buffer capacity? 4. Explain the difference in the value of the calculated pH and the experimental pH of the buffer solution you prepared.

Exercise 1. How would you prepare 500.0 ml of 0.050 M phosphate buffer solution, pH 6.7 from 0.20 M solutions of acid and salt?

2. What will be resulting pH of the buffer in question # 1 if the following are added: A) 1.0 ml of 1.0 M HCl b) 1.0 ml of 1M NaOH?

3. Compare the results in question # 2 if these reagents were added to 500 ml of distilled water instead? Interpret your results.

Experiment 3: PROTEINS AND AMINO ACIDS A. Qualitative Tests and Analysis of Unknown

Obtain an unknown sample from your instructor. This is to be subjected to the following qualitative tests

necessary for its identification. Use distilled water as the negative control. Use small test tubes. Use a 250 mL beaker half-filled with water for the hot water bath. Throw all solutions in a labeled waste crock after the experiment. (Reminder: Bring raw egg and skimmed milk).

1. Biuret Test

To 10 drops of sample (1% albumin, 0.1% valine and unknown), add 10 drops of 10% NaOH solution and 1 drop of 0.1% CuSO4 solution. Mix well.

2. Ninhydrin Test

Add 10 drops of 0.1% ninhydrin to 20 drops of sample (1% albumin, 0.1% valine, and unknown) and heat the mixture in a water bath for 2 minutes. Cool. Note the color produced. 3. Xanthoproteic Test

To 10 drops of sample (1% albumin, 0.1% valine, 0.1% phenylalanine, 0.1% tyrosine, 0.1% tryptophan and unknown), add 5 drops of concd HNO3. Place in boiling water bath for 5 minutes. Note the color. Cool the solution. Add 20% NaOH until the solution is alkaline. Note any color change. 4. Millon-Nasse Test

Add 2 drops of Millon-Nasse reagent to 10 drops of sample (1% albumin, 0.1% valine, 0.1% tyrosine and unknown) and heat the mixture in boiling water bath for 5 minutes. Cool and add 2 drops of 0.1% NaNO2. Note any color change.

5. Hopkins-Cole Test

Mix 10 drops of glyoxylic acid with 10 drops of sample (1% albumin, 0.1% valine, 0.1% tryptophan and unknown). Add 2 mL of concd H2SO4, pouring it carefully down the side of the inclined tube so that the liquids do not mix. Allow to stand for approximately 10 minutes. Observe.

6. Sakaguchi Test

To 10 drops of sample (1% albumin, 0.1% valine, 0.1% arginine and unknown), add 5 drops of 10% NaOH to ensure an alkaline medium. Add 2 drops of dilute a-naphthol in alcohol solution and mix thoroughly. Add 3 drops of NaOBr. Note the color change.

7. Lead Acetate Test

To 10 drops of sample (1% albumin, 0.1% valine, 0.1% cysteine and unknown) and 3 hair strands, add 10 drops of 20% NaOH and 1 drop of 10% Pb(OAc)2. Cover the test tube with marble and heat in water bath for about 5 minutes. Note the color. B. Precipitation Reactions 1. Heat and Acid

Place 10 drops of 10% albumin in two separate test tubes. Add 1 drop of 5M HOAc to the second tube. Gently boil the contents and compare results.

2. Alcohol

Add 10 drops of ethanol to 10 drops of 10% albumin solution. Observe the appearance of the precipitate formed.

Experiment 3: PROTEINS AND AMINO ACIDS 3. Alkaloidal Reagents

To 10 drops of 10% albumin, add 2 drops of picric acid. Repeat using 2 drops of TCA. Observe.

4. Heavy Metal Salts To 5 drops of 10% albumin, add 2% CuSO4 dropwise until a precipitate forms. Repeat using 2%

FeCl3. Note down your observations. 5. Salting-Out

Place 10 drops of albumin solution in 2 separate test tubes. To one tube, add solid (NH4)2SO4 until no more of the salt dissolves. To the other tube, add solid NaCl until no more salt dissolves. Compare results.

6. Isoelectric Point Measure 20.0 mL of skimmed milk and pour in a 50 mL beaker. Check the initial pH of skimmed

milk. Add 0.05 M HCl dropwise with stirring (Handle the electrode carefully) until the pH reaches 4.5. Transfer the mixture into 2 small separate test tubes labeled 1 & 2. Centrifuge for 3 minutes. Discard the supernate. To test tube 1 add 10 drops of 1M HCl and observe what happens. To test tube 2 add 10 drops of 1M NaOH and observe. C. Analysis of Amino Acids by Paper Chromatography

Use a piece of filter paper (about 5 by 4 square inches). Draw a line using a pencil on oneside of the paper 1 cm from the edge. Mark 6 points along this line on which you will introduce your amino acid standards and unknown. Place a drop of each sample on the designated spot. Allow the samples to dry. Add another drop if necessary. Form a cylinder by connecting one end of the paper with the other (do not overlap) using a masking tape. Slowly place the paper in a beaker/jar containing sufficient amount of solvent (n-butanol:HOAc:H2O;100:22:50). Make sure that the baseline is not submerged in the solvent. Cover with watch glass. Do not disturb the system while the run is going on. When the solvent is about 2 cm from the upper edge, remove the paper from the bath and mark the solvent front using your pencil. Dry the paper then spray with 0.1% ninhydrin solution. Blow dry the paper and carefully encircle the spots using your pencil. Calculate the Rf value of the amino acids and unknown. [Rf = D/L where D = distance traveled by the solute/sample and L = distance traveled by the solvent] Questions: 1. A very dilute solution of CuSO4 is used in Biuret test. Why? 2. Name the test that will differentiate between

a. proline and alanine b. a dipeptide and a tripeptide c. an aromatic and aliphatic amino acid d. tyrosine and tryptophan e. arginine and alanine f. cysteine and alanine

3. What is the basis of the separation of amino acids in paper chromatography? Explain the Rf values obtained and relate these to the structures of the amino acids. 4. Explain the molecular basis of the following

a. egg white as antidote for lead poisoning b. vinegar in making kilawin c. hard-boiled egg white being more digestible than raw egg white

Experiment 3: PROTEINS Worksheet Names: Section: Group Number: Date:

A. Qualitative Tests and Analysis of Unknown

Test Solution Biuret Test Ninhydrin Test

Xanthoproteic Test

Millon-Nasse Test

Hopkins-Cole Test

Skaguchi Test

Lead Acetate Test

1% Albumin

0.1% Valine

0.1% Phenylalanine

0.1% Tyrosine

0.1% Tryptophan

0.1% Arginine

0.1% Cysteine

Hair strands

Distilled water

Unknown

Unknown #: Identity: Comments:

Experiment 3: PROTEINS Worksheet B. Precipitation Reactions 1. Heat and Acid

10% albumin + heat ___________________________________ 10% albumin + heat + 5M HOAc ___________________________________

2. Alcohol

10% albumin + ethanol ___________________________________ 3. Alkaloidal Reagents

10% albumin + picric acid ___________________________________ 10% albumin + TCA ___________________________________

4. Heavy Metals

10% albumin + 2% CuSO4 ___________________________________ 10% albumin + 2% FeCl3 ___________________________________

5. Salting-out

10% albumin + solid (NH4)2 SO4 ___________________________________ 10% albumin + solid NaCl ___________________________________

6. Isoelectric Point

Initial pH of skimmed milk ___________________________________ Casein + 1.0 M HCl ___________________________________ Casein + 1.0 M NaOH ___________________________________

C. Analysis of Amino Acids by Paper Chromatograpy

Amino Acid Distance traveled by solute (cm) Distance traveled by solvent (cm) Rf

Unknown #

Identity: Comments:

Experiment 4: ENZYME DIGESTION Throw all solutions in the sink. Bring boiled egg white. I. Digestion of Proteins 1. Label and prepare three test tubes as follows:

2. Add a very small piece of boiled egg white, the protein substrate. Use equal sizes of egg white. Place in a water bath at 37C for one and a half hours. Record any changes observed in the egg white in each test tube. (Remove the undigested egg white before throwing the solution in the sink)

II. Digestion of Carbohydrates A. HYDROLYSIS OF STARCH BY SALIVARY AMYLASE 1. In a small beaker, collect 5 mL of saliva. Add 10 mL of distilled H2O. Mix well. This solution will be the source of salivary amylase.

2. To four test tubes labeled A, B, C, and D, transfer 2.00 mL of 2% starch solution. Add 4.00 mL of distilled water to test tubes A and B (control samples). To test tubes C and D, add 4.00 mL of the saliva solution.

3. Place all four test tubes in a water bath maintained at 37C for 30 minutes. 4. Remove the test tubes from the water bath. 5. Perform Fehlings Test to test tubes A and C. Record your observations. 6. Perform Iodine Test to test tubes B and D. Record your observations. B. HYDROLYSIS OF STARCH BY PANCREATIC AMYLASE 1. Label four test tubes. Prepare each test tube as described below:

Experiment 4: ENZYME DIGESTION 2. To each test tube, add 2.00 mL of 2% starch solution. Stopper and gently shake each test tube to mix the contents. 3. Place all test tubes in the water bath maintained at 37C for 30 minutes. 4. After heating, pour half the contents of each test tube into another test tube of the same size (labeled E-2, F-2, G-2, and H-2). 5. Perform Fehlings Test to the remaining solutions in test tubes E, F, G, and H. Observe and record your results. 6. Add 2 drops of I2 in KI solution each to each test tube labeled E-2, F-2, G-2 and H-2. Record your observations. Questions: 1. Digestion in the mouth:

a. What are the optimum conditions for the action of salivary amylase? b. What are the end products?

2. Digestion in the stomach: a. What are the optimum conditions for the action of pepsin? b. What are the end products?

3. Digestion in the small intestine: a. What are the optimum conditions for the action of pancreatic amylase? b. What are the optimum conditions for the action of pancreatic lipase? c. What are the end products? d. What is the role of bile salts?

4. Monitor the digestion of a meal which consists of the following: Tapsilog + milk + chiffon cake

Experiment 4: ENZYME DIGESTION Worksheet Names: Section: Group Number: Date:

Experiment 5: EFFECT OF SUBSTRATE CONCENTRATION ON ENZYME ACTIVITY

Throw all solutions in a labeled waste crock. I. Enzyme Collection

Collect 1.0 mL of saliva. Place in a 50 mL beaker and add 9.0 mL of distilled water. Mix well. Use this solution as the source of enzyme.

II. Preparation of the Standard Curve 1. Using large test tubes, prepare the following samples:

2. Cover the test tubes with aluminum foil and place in boiling water bath for 5 minutes. 3. Cool the samples by immersing in tap water. Dilute each to 25 mL with distilled water and take the absorbance against a blank. Mix well. Data Processing: Standard Curve 1. Plot Absorbance vs. mg Glucose. A linear graph will be obtained based on the equation A = mx + b where A = absorbance, x = mg Glu, m = slope and b= y-intercept 2. Obtain m and b. These values will be used in the Assay Data processing.

Experiment 5: EFFECT OF SUBSTRATE CONCENTRATION ON ENZYME ACTIVITY

III. Assay for a-amylase Reagents: Saliva solution (enzyme)

1% starch solution (substrate) 0.10 M phosphate buffer, pH = 7 (buffer) 0.9% NaCl solution Dinitrosalicylic acid (DNS) reagent

1. Place the following reagents (in the order: substrate, buffer, NaCl solution, enzyme) in marked test tubes, according to the volumes specified below.

2. Mix well. Allow hydrolysis to proceed at room temperature for 15 minutes. 3. Stop the hydrolysis reaction by adding 1.00 mL of DNS reagent and place in boiling water bath for 5 minutes. Cover each test tube with aluminum foil to prevent evaporation while heating. 4. Cool the test tubes. Dilute each to 25 mL with distilled water. Mix well. 5. Determine the absorbance of the solutions against a blank or control at 540 nm in the Vis Spectrophotometer (Spectronic 20). 6. Plot REACTION VELOCITY vs. SUBSTRATE CONCENTRATION and determine the Km and Vmax. Data Processing: Assay for a-amylase 1. Calculate mg Glucose using the equation from the Standard curve: mg Glucose = (A b)/m 2. Calculate the velocity using the formula V = mg Glucose/15 minutes 3. Plot V vs mg of substrate (Michaelis-Menten equation). Determine KM and Vmax. 4. Plot 1/V vs 1/mg substrate (Lineweaver-Burke equation). Determine KM and Vmax. ***You may use the volume instead of the amount in mg for plotting.

The Michaelis-Menten Equation The Lineweaver-Burke Equation

Questions: 1. Compare the values of KM and Vmax obtained from each plot. 2. Discuss the effect of the following on enzyme activity:

a. enzyme concentration b. pH c. temperature

Experiment 5: EFFECT OF SUBSTRATE CONCENTRATION ON ENZYME ACTIVITY

Names: Section: Group No: Date:

Experiment 6: LIPIDS Qualitative Tests and Analysis of Unknown

Obtain an unknown sample from your instructor. This is to be subjected to the following qualitative tests necessary for its identification. Chloroform (CHCl3) will be the negative control. Use small, dry test tubes. Use a 250 mL beaker half-filled with water for your hot water bath. Throw all solutions in a labeled waste crock after the experiment. 1. Acrolein Test

Place a pinch of KHSO4 and 2 drops/a pinch of each sample (glycerol, coconut oil, stearic acid and unknown) in 3 separate test tubes. Heat gently at first and then vigorously. Abrupt heating is not recommended because it will result in the formation of SO2 which would obscure the odor due to the acrylic aldehyde. Describe the odor produced.

2. Test for Unsaturation

To 5 drops/a pinch of each sample in separate test tubes (olive oil, oleic acid, stearic acid, coconut oil and unknown), add Br2-H2O dropwise until the reagent is no longer decolorized in the mixture. Use the same dropper for all samples since you have to record the number of drops used.

3. Test for Phosphate

Incinerate a small amount of lecithin (pea size) in a porcelain crucible. Extract the cooled residue with 3 mL distilled water. Filter. To 1 mL filtrate, add 10 drops of freshly prepared 5% (NH4)2MoO4 and 2 drops concentrated HNO3. Heat to boiling and allow it to stand.

4. Emulsification Test

Prepare the following mixtures in separate test tubes. Test Tube Contents

A 20 drops coconut oil + 20 drops of 1% bile salt solution B 20 drops coconut oil + 20 drops of 1% lecithin solution

Shake the mixture and observe results. 5. Liebermann-Burchard or Acetic Anhydride Test

Dissolve a pinch of cholesterol in 10 drops of CHCl3, then add 3 drops of acetic anhydride and 1 drop of concentrated H2SO4. Mix. Note changes in color.

6. Modified Furter-Meyer Test (Test for Vitamin E)

To 10 drops of 0.05% of a-tocopherol in CHCl3, add 2.0 mL of n-butyl alcohol and 5 drops of concentrated HNO3. Mix and place the tube in a water bath at 80C for 10 minutes. Note the change in color.

Questions: 1. What qualitative tests can be done to detect the presence of vitamin A? Discuss the test in detail. 2. What is the significance of iodine number? 3. What is the significance of saponification number? 4. Which qualitative test should be used to differentiate between

a. glycerol and stearic acid b. coconut oil and stearic acid c. glycerol and olive oil d. linoleic acid and stearic acid e. vitamin E and vitamin A f. cholesterol and coconut oil g. lecithin and coconut oil

5. Enumerate the fat-soluble vitamins. 6. What is the purpose of lecithin in the preparation of mayonnaise?

Experiment 6: LIPIDS Worksheet Names: Section: Group Number: Date: I. Qualitative Tests and Analysis of Unknown

Sample Acrolein Test Test for Unsaturation Test for Phosphate

Emulsification Test

Liebermann-Burchard Test

Furter-Mayer Test

Glycerol

Coconut oil

Olive oil

Oleic acid

Stearic acid

Lecithin

Bile Salt

Cholesterol

a-Tocopherol

CHCl3

Unknown

Experiment 7: NUCLEIC ACIDS I. Isolation 1. Weigh 1 gram of ground beef or pork liver and suspend in 4 mL of ice cold water. Homogenize using mortar and pestle.

2. Add 5 mL of cold 2.5% TCA and mix well. Centrifuge for 2 minutes and discard the supernate.

3. Resuspend in 2.5 mL 2.5% TCA. Allow to stand for 5 minutes and centrifuge for 2 minutes. Discard the supernate.

4. Add 5 mL of 95% ethanol and centrifuge for 2 minutes. Repeat one more time. 5. Resuspend the remaining pellet in 1.3 mL of water + 1.3 mL of 10% TCA and heat for 15 minutes in a water bath. Centrifuge for 2 minutes and collect the supernate.

6. Resuspend the pellet in 2.5 mL of 5% TCA. Centrifuge for 2 minutes, collect the supernate.

7. Combine the supernates obtained. This will be your DNA solution. II. Qualitative Tests

Use small test tubes. Use a 250 mL beaker half-filled with water for the hot water bath. Throw all solutions in a labeled waste crock after the experiment. A. Test for Nucleoproteins

To 20 drops of the DNA solution, add 10 drops of 10% NaOH and 5 drops of 0.5% CuSO4 solution. Observe. B. Test for Nucleic Acid Hydrolysis Products

Add 5 mL of 10% H2SO4 to 3 mL of the DNA solution. Boil gently for a few minutes. This will serve as the hydrolysate. Perform the following: 1. Presence of Purines. Add 20 drops of 10% KOH to 10 drops of the hydrolysate. Mix. Add 3 drops of HNO3 solution. Note the results. 2. Presence of Ribose. Mix 20 drops of Bial's Orcinol reagent to 20 drops of the following solutions in separate test tubes: 0.1% ribose, 0.1% glucose and hydrolysate. Place the test tubes in boiling water bath until a color develops and note this color change. 3. Presence of Deoxyribose: Add 20 drops of diphenylamine to 20 drops of the following solutions: 0.1% ribose, 0.1% glucose, and hydrolysate. Place in a boiling water bath until a color develops. Record results. 4. Presence of Phosphates. To 20 drops of hydrolysatesolution, add 20 drops of 10% HNO3 and 20 drops of 5% (NH4)2MoO4 solution. Heat to boiling. Let it stand for a few minutes and note the result/s.

Experiment 7: NUCLEIC ACIDS Worksheet Names: Section: Group Number: Date: I. Isolation Appearance of Solution _________________________________________ II. Qualitative Tests A. Test for Nucleoproteins _________________________________________ B. Test for Nucleic Acid Hydrolysis Products

1. Presence of Purines

DNA solution _________________________________________ 2. Presence of Ribose

DNA solution _________________________________________ Glucose _________________________________________ Ribose _________________________________________

3. Presence of Deoxyribose

DNA solution _________________________________________

Glucose _________________________________________

Ribose _________________________________________ 4. Presence of Phosphates

DNA solution _________________________________________