BIO 101 Lab 02, Macromolecules (no lab simulation) PDF

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This document has the lab answers and graphs....

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas.

BIO 101 Lab 02: Chemistry. Introduction to macromolecules, organic molecules abundant in living systems. Notification: If you have a disability that makes it difficult to complete this lab, please contact your instructor. Please provide your instructor a copy of the Memorandum of Accommodation (MOA) from NVCC Disability Support Services. Objectives:____________________________________________________________   

Describe the basic structures and properties of monomers and polymers of carbohydrates, proteins and lipids. Identify reagents and positive test results for simple sugar, starch, proteins and lipids Explain how to determine nutritional components of foods based on biochemical analysis

Background:__________________________________________________________ All of chemistry is divided into two sections: organic chemistry and inorganic chemistry. Basically, organic chemistry deals with carbon compounds and inorganic chemistry is everything else. Organic compounds come in many different forms, in this lab we will analyze three of them: carbohydrates, lipids, and proteins. Each of these classes is vital to living things. Each also contains numerous different chemicals of various levels of complexity. Carbohydrates Carbohydrates are organic molecules consisting of only carbon, oxygen and hydrogen atoms bonded together. Carbohydrates are energy molecules. They are the fuel that our bodies burn to maintain life. Sugars containing one glucose-like molecule are called monosaccharides from Greek and Latin words meaning “one sugar”. Similarly sugars containing two glucose-like molecules are called disaccharides meaning “two sugars”. Starches are composed of many of these small sugar molecules joined together and are technically called polysaccharides (“many sugars”). In a more general sense the glucose-like molecules can be considered monomers – “one part” – and the long chains polymers – “many parts”. Therefore starch is a polymer, and so are most of the other organic molecules we will be looking at in this lab. These polymers are formed by a process known as dehydration synthesis (or condensation synthesis) – “putting together by removing water.” This can be visualized by the following equation:

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas.

In today’s lab, you will be testing for the presence of carbohydrates with two separate chemical reagents: iodine and Benedict’s solution. Iodine will stain starch (a complex carbohydrate) a dark blue or black color and Benedict’s will turn green, yellow, orange or red in the presence of various concentrations of simpler sugars (such as glucose). On this scale green indicates a low concentration, red indicates a very high concentration. Proteins Proteins are polymers composed of monomers known as amino acids. There are twenty of these amino acids, each has the -NH 2 group at one end and the –COOH group at the other, thus the whole molecule is an amino acid. The R stands for radical group, and can be any of twenty different atoms or atom groups making for the twenty different amino acids. During dehydration synthesis the –OH group from the carboxylic acid end and one of the hydrogens from the amine group are removed and form a water (H 2O) molecule. What remains of the two amino acids joins with a peptide bond between the C and the N, forming a dipeptide.

This process can continue indefinitely to form a polypeptide. This polypeptide chain is arranged in a complex three-dimensional form that is covered in your lecture text. Changes in this three-dimensional structure may cause the protein to not be able to perform its function. A protein that has been changed in this way is said to be denatured. Proteins perform many functions in living cells. There are structural proteins, storage proteins, transport proteins, contractile proteins, proteins that speed up reactions, proteins that fight infection, proteins that regulate life processes and proteins that detect chemical signals. You will be testing for the presence of peptide bonds or full proteins with Biuret reagent. Biuret will turn purple in the presence of proteins or pink in the presence of smaller peptide fragments. Lipids

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas. Lipids are not a single type of molecule; rather, they are various types of organic molecules that are poorly soluble in water. The lipids most familiar to the general public are the fats and oils. While also performing structural duties, their major function is to store energy for later use by the organism. While not really polymers, lipids are still formed via dehydration synthesis between their parts. The fats and oils are composed of glycerol and several fatty acids. Again, dehydration joins the fatty acids to the glycerol through the removal of water to form an ester linkage (an oxygen atom bonded between two carbons). Typical fats and oils have 3 fatty acids attached to the glycerol. All of this may be made clearer by the following diagram showing glycerol, fatty acids and their linkage. The common feature of lipids is that they are hydrophobic, which means they do not mix with water easily. You will test the presence of lipids by using the Sudan IV reagent, which dissolves more effectively in lipids or fats, forming a red color.

A fourth major type of organic macromolecule consists of nucleic acids. The nature of these molecules will be covered in depth in a later lab. Materials:_____________________________________________________________ 

Internet

Safety: Follow all standard laboratory safety procedures. Test tubes incubated in the hot water bath will be HOT to the touch. Use the tongs to remove the tubes from the hot water bath. Place hot tubes directly into tube rack. Procedure:___________________________________________________________ Experiment 1. Positive and negative tests for organic molecules

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas. 1. Watch the following video about testing for the presence of simple sugars using Benedict’s Reagent from time 0:00 until 1:36 https://www.youtube.com/watch?v=Lt7RCIfudYQ&t=31s 2. In the laboratory, you would take two small test tubes and label them as “B-G” and “BW” plus your initials. You would add 20-30 drops of glucose solution to the “G” tube, and add 20-30 drops of water to the “W” tube. Then, you would add 5 drops of Benedict’s solution to each tube. You would place the tubes in a beaker of hot water and incubate them for 5 minutes. You would then observe the changes (if any) in the solutions. You should record your observations of the the final color of the solution in each tube in Table 1 of the Lab Worksheet. The experimental setup and results should look like this:

3. Watch the following video about testing for the presence of starch using Iodine from time 0:00 until 1:09 https://www.youtube.com/watch?v=J5eaJc854uQ 4. In the laboratory, you would next take two small test tubes and label them as “I-S” and “I-W” plus your initials. You would add 10-20 drops of starch solution to the “S” tube and add 10-20 drops of water to the “W” tube. Then, you would add 5 drops of Iodine to each of the test tubes. The reaction between iodine and starch should occur immediately. Record final color of each mixture in Table 1 of the Lab Worksheet. The experimental setup and results should look like this:

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas.

5. Watch the following video about testing for the presence of proteins using Biruet Solution from time 0:00 until 1:43 https://www.youtube.com/watch?v=L4Rjpp8x9-A 6. In the laboratory, you would next take two small test tubes and label them as “U-A” and “U-W” plus your initials. You would add 10-20 drops of Albumin solution to the “U-A” tube one and add 10-20 drops of water to the “U-W” tube. Then, you would add 5 drops of Biuret solution to each of the test tubes. The reaction between the Biuret solution and the protein (albumin) should occur immediately. Record final color of each mixture in Table 1 of the Lab Worksheet. The experimental setup and results should look like this:

7. Watch the following video about testing for the presence of lipids using Sudan IV 0:00 until 1:24 https://www.youtube.com/watch?v=QTTn2-rZhuM

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas. 8. In the laboratory, you would next take two small test tubes and label them as “S-O” and “S-W” plus your initials. You would add 10 drops of water and 10 drops of Vegetable Oil to the “S-O” tube. Then, you would add 20 drops of water to the “S-W”. Next, you would add 5 drops of Sudan IV solution to each tube. You would then shake the tubes to mix them. Oil tends to float on top of water since oil is less dense than water. The Sudan IV dye will associate more strongly with oil than it will with water, which will cause a colored layer of fluid to appear if oils (lipids) are present. Record final color of each mixture in Table 1 of the Lab Worksheet.

The experimental setup and results should look like this:

Experiment 2. Tests with foods The foods you will test are: potatoes, orange juice, almonds, eggs, and whole milk. 1. Based on your knowledge about the available food items, make predictions about the which macromolecules will be present in each food sample and record your predictions in Table 2 of the Lab Worksheet. 

For example, if you think the food sample contains simple sugars, place a “+” in the Simple Sugars column in the row corresponding to that food sample. If you instead think the food sample does not contain simple sugars, place a “ ‒” in that column.

2. In the laboratory, you would then obtain the food items. For solid food samples, you would use a razor blade or spatula to obtain a pea sized portion of food. Then, you would place the food sample into a large test tube and add 10ml of water. Next, you BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas. would place a clean gloved thumb on top of the test tube and shake vigorously for one minute to break up the food and dissolve as much as possible into the water. The resulting solutions would then be used in your experiments. You would also obtain 5ml of milk in a separate test tube for testing. 3. You would then perform the Benedicts test on each food sample. You would label five small test tubes, one for each food sample. You would then add approximately 1 mL (or 20-30 drops) of each prepared food sample solution (from step 2 above) to the appropriately labeled test tube. You would next add 5 drops of Benedict’s reagent to each tube. Then, you would incubate all the tubes in a hot water bath for 5 minutes. Based on the color change results and your previous experiments, record whether or not each food sample contains simple sugars in Table 3 of the Lab Worksheet. The experimental setup and results should look like this:

4. Next, you would perform the iodine test. Again, you would label five small test tubes, one for each food sample. You would then add approximately 1 mL (or 20-30 drops) of each prepared food sample solution (from step 2 above) to the appropriately labeled test tube. You would next add 5 drops of Iodine solution to each tube. Based on the color change results and your previous experiments, record whether or not each food sample contains starch in Table 3 of the Lab Worksheet. The experimental setup and results should look like this:

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas.

5. Then, you would perform the Biuret solution test. Again, you would label five small test tubes, one for each food sample. You would then add approximately 1 mL (or 20-30 drops) of each prepared food sample solution (from step 2 above) to the appropriately labeled test tube. You would next add 5 drops of Biuret solution to each tube. Based on the color change results and your previous experiments, record whether or not each food sample contains protein in Table 3 of the Lab Worksheet.

The experimental setup and results should look like this:

6. Finally, you would perform the Sudan IV test. Again, you would label five small test tubes, one for each food sample. You would then add approximately 1 mL (or 20-30 drops) of each prepared food sample solution (from step 2 above) to the appropriately labeled test tube. You would next add 5 drops of Sudan IV solution to each tube. Based on the color change results and your previous experiments, record whether or not each food sample contains lipids in Table 3 of the Lab Worksheet. The experimental setup and results should look like this: BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas.

7. Complete the Lab Worksheet by answering any remaining questions.

BIO 101 Lab 02: Chemistry. Introduction to macromolecules Worksheet Name: _____Claudia Ferman_______________________ Section:__________________ Data Analysis and Synthesis Questions: 1. What are the small subunits (monomers) found in each of these types of organic compounds: protein:_________amino acids___________ starch: _______glucose______________ lipid:

________Fatty acids_____________, and ______glycerol_______________ Table 1. Positive and Negative Controls

Reagent

Substance Tested

Appearance after test

Glucose

Orange/red

Water

clear

Starch

Black

Benedict’s Iodine

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas.

Biuret

Sudan IV

Water

Clear

Albumin

Light Purple

water

Clear

Oil

Dark red at the top

Water

amber

2. In the Benetict’s test, the Benedict’s reagent tests for simple sugars, e.g. glucose.

a. Name the color of the reaction when glucose in present. ___red______________ b. Water will act as a negative control because it does not contain any sugar.

3. In the Iodine test, Iodine tests for starch, a complex carbohydrate.

a. The color of the tube when iodine is added to starch is _____Black_______. b. The color of the tube indicated in part (a) above is is a __Positive____________ (positive or negative) test result for the presence of complex carbohydrates. 4. In the Biuret test, the Biuret reagent tests for proteins. Describe the change that occurs when Biuret reagent is added to the test tube when proteins are present.

It turned the solution purple.

5. An unknown sample has been tested with Biuret and with Benedict’s solution. a. The Biuret test resulted in a blue color. Based on this test result, what can you determine about the molecule(s) present in the unknown sample?

It means had proteins and no glucose. BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas.

b. The Benedict’s test resulted in a blue color. Based on this test result, what can you determine about the molecule(s) present in the unknown sample?

It tested negative for glucose.

6. In the Sudan IV test, Sudan IV tests for lipids or fats. a. The common feature of lipids is that thy do not mix with water. Therefore, lipids and fats are called __Hydrophobic___________

b. Explain why there are two layers when vegetable oil was added to the water. The oil is hydrophobic and doesn’t mix with the water because of its nonplolar properties.

i. Which layer of the oil and water mixture turns red in color? The lipids layer. The top layer turned dark red because it had lipids.

Table 2. Predicted Macromolecule Composition: Presence (+) or Absence (-) BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas. Food

Simple Sugars -

Starch +

Protein -

Lipids +

Orange Juice

+

-

-

-

Almonds

+

-

+

-

Eggs

-

-

+

+

Whole Milk

-

-

+

+

Potato

Table 3. Record if the test was Positive (+) or Negative (-) for each food sample Food Benedict’s Iodine Biuret Sudan IV Potato

-

+

-

-

Orange Juice

+

-

-

-

Almonds

-

-

+

+

Eggs

-

-

+

-

Whole Milk

+

-

+

+

7. Draw a conclusion for each prediction made. Summarize your results then compare your predictions to the data, and accept or reject your hypothesis. ● Write a conclusion for each test. ● If your results match the prediction you made for foods that will test positive for that molecule, accept your hypothesis. ● If your results match the prediction you made the foods that will test positive for that molecule reject your hypothesis. a. Write a conclusion for the test for simple sugars. My conclusion based on the results is that Orange juice and whole milk has simple sugars in it and almonds, eggs, and potatoes don’t. My hypothesis was incorrect I had predicted that orange juice and almonds would test positive for simple sugars.

b. Write a conclusion for the test for starch.

BIO 101 Lab 02: Macromolecules

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To submit this assignment, students will complete the Lab Worksheet on pages 18-21, then upload their completed document as a DOC or PDF file in Canvas. My conclusion is that the potato tested contains starch based in on the iodine test but Almonds, orange juice, eggs, and whole milk don’t. My hypothesis was correct.

c. Write a conclusion for the test for protein. My conclusions based on the results were that almond, eggs, and whole milk would text positive for protein. My hypothesis was proven correct by these results.

d. Write a conclusion for the test for lipids/fats. My...