Biology Commonwealth of Virginia

Part 1. Macromolecules

Materials

• 
  Internet access
  
• 
  Molecular model kit (optional)
  

Introduction

2. Complete the information for each macromolecule. The following Web site will be helpful: http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20100/Bio%20100%20Lectures/Biochemistry/biochemi.htm.

Observations

2. Which elements are present in all four types?

3. Draw an atomic model for carbon.

4. Draw a Lewis diagram for carbon.

5. What is it about the electron structure of carbon that makes it so flexible in making different biomolecules?

6. What are the monomer units of a protein called?

7. Using the text or Web site listed above, draw a general structure of an amino acid (or use a molecular model kit to make a model of it), and use the drawing or model to show how a peptide bond forms.

Part 2. Fats and Carbs (Lipids and Carbohydrates): Good Guys with a Bad Rep

(Note: Start this at beginning of class to allow adequate time for slow heating.)

Materials

• 
  Vegetables or fruits, diced or cut in very small pieces
  
• 
  Flour or bread (whole grain and white; crumbs are best)
  
• 
  Oil (1 mL)
  
• 
  Nuts — any kind, ground or chopped
  
• 
  Bacon, cut into small pieces
  
• 
  Hotdog or hamburger, cut into small pieces
  
• 
  Snack foods — crackers, chips, cheese doodles, or similar foods, crushed
  
• 
  Heat source — microwave, hot plate, hot water bath, or heating pad
  
• 
  Brown butcher paper or brown grocery sack
  
• 
  Paper plate or water-proof container
  

Procedure

2. Place a small amount of a sample on a square.

3. Fold or wrap the samples as tightly as possible, and place them on a paper plate. If you are using a hot water bath, place the plate in a water-proof container.

4. Heat the samples during the remainder of the period.

5. Remove heat source, and open the squares.

6. Record in Table 2 which samples left a translucent spot (grease spot, indicating presence of fat/oil) on the paper.

Observations

2. Did any samples give surprising results?

3. Judging from the Function of Lipids column, are lipids important in our diets, or are they not really necessary?

4. Do we need lipids/fats in our diets?

Materials

• 
  Sugar
  
• 
  Molasses
  
• 
  Honey
  
• 
  Cornstarch
  
• 
  Potatoes
  
• 
  Vegetables or fruits, diced or cut in very small pieces
  
• 
  Flour or bread (whole grain and white; crumbs are best)
  
• 
  Nuts, bacon, hotdog, or hamburger, chopped cut into small pieces
  
• 
  Snack foods — crackers, chips, cheese doodles, or similar foods
  
• 
  Benedict’s solution
  
• 
  Iodine
  
• 
  Test tubes or micro well plates
  
• 
  Beakers to hold test tubes
  
• 
  Heat source — hot water bath, heater, heating pad, or microwave
  
• 
  Pipettes
  

Procedure

1. Make a solution (add small amount of water and stir) in a test tube of the substance to be tested, and pipette approximately 2–3 mL Benedict’s solution into the tube.

2. Alternatively, pipette 2–3 mL Benedict’s solution into a tube onto a small chunk of fruit, vegetable, bread, snack food, meat, nut, etc.

3. Heat the tube gently in a hot water bath for about 2 minutes. A color change from blue to green to yellow/orange/red indicates the presence of a simple (reducing) sugar.

4. Record results in Table 3.
Iodine test for starch

1. Add 1–5 drops of iodine solution directly to the sample solid food or solution.

2. The result is almost instantaneous, but allow iodine to soak into solids. A color change from orange to blue-black shows the presence of starch.

3. Record results in Table 3.

Observations

2. Are the lipid/fat and carbohydrate tests qualitative or quantitative?

3. Judging from the Function of Carbohydrates column, are carbohydrates important in our diets, or are they not necessary? Why, or why not?

Part 3. Proteins, Amino Acids, and Enzymes: The Effect of Heat and Acid on the Enzyme Peroxidase

Introduction

Hydrogen peroxide is produced as a “waste product” in eukaryotic cells. It is a metabolic poison (toxin), which needs to be decomposed fairly quickly to maintain health. Peroxidase is an enzyme found in many living organisms that decomposes (breaks down) hydrogen peroxide into oxygen and water. This process is easily studied in potatoes. If peroxidase is present and functioning properly, there will be decomposition (gas evolution) clearly obvious in the tubes. In the presence of heat or acid, which denatures (breaks apart the bonds) the protein (the enzyme peroxidase), there will be no decomposition.

Materials

• 
  Hot water bath
  
• 
  Potato cubes (1 to 2 cubic centimeters)
  
• 
  3 percent hydrogen peroxide solution
  
• 
  Pipette
  
• 
  Test tubes
  
• 
  Citric or acetic acid solution — lemon juice or vinegar
  

Procedure

Observations

2. In the above equation, which is the substrate?

3. What is the function of an enzyme?

4. What happened to the enzyme in the boiling water?

5. What happened to the enzyme in the acid solution?

6. Which tube(s) was/were the control?

7. Write a hypothesis for this experiment.

Part 4. Nucleic Acids: Extracting DNA from Dried Split Peas

Introduction

Materials

• 
  Dried split peas
  
• 
  Salt
  
• 
  Liquid detergent
  
• 
  Meat tenderizer
  
• 
  Rubbing or ethyl alcohol
  
• 
  Cold water
  
• 
  Test tubes
  
• 
  Strainer
  
• 
  Blender
  
• 
  Toothpicks
  

Procedure

2. Measure 2/3 cup of dried split peas. Add about 1/8 teaspoon of salt and 1-1/3 cups of cold water. Mix the ingredients in a blender on high speed for 15 seconds.

3. Pour the pea mixture through a strainer into another container. Add about 2 tablespoons of liquid detergent to the mixture. Let it sit for 5 to 10 minutes.

4. Pour the mixture into 3 test tubes or smaller containers so that each is 1/3 full. Then add a pinch of meat tenderizer to each container and stir gently.

5. Tilt each test tube and slowly pour rubbing alcohol (70–95 percent isopropyl or ethyl alcohol) down the inside wall of the tube so that it forms a layer on top of the mixture. Keep pouring in alcohol until the tube contains about the same amount of alcohol as it does pea mixture.

6. In a few minutes, the DNA will rise into the alcohol layer from the pea mixture layer. You can use a toothpick to pull the DNA out.

Observations

2. Describe the DNA: What is its texture? Does it have an odor?

Sample Released SOL Test Items

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scope sequence -> History and Social Science Standards of Learning Enhanced Scope and Sequence
sol -> Strand Earth Patterns, Cycles, and Change Topic Investigating fossils in sedimentary rock Primary sol
testing -> Prairie State Achievement Exam
testing -> Testing and Assessment updated Tentative schedules
testing -> Local unit tests Located at module-name
sol -> P. O. Box 2120 Richmond, Virginia 23218-2120
sol -> Strand Interrelationships in Earth/Space Systems Topic Investigating ocean currents Primary sol
sol -> History and Social Science Standards of Learning for Virginia Public Schools Wo Board of Education Commonwealth of Virginia March 2015 History and Social Science Standards of Learning for Virginia Public Schools Adopted in March 2015 by the Board of

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