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Name: Brayden Casey Date: 04-20-2022 Student Exploration: Dehydration Synthesis Directions: Follow the instructions to go through the simulation. Respond to the questions andprompts in the orange boxes. Vocabulary: carbohydrate, chemical formula, dehydration synthesis, disaccharide, glucose, hydrolysis, monosaccharide, polysaccharide, valence Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. If you exercise on a hot day, you need to worry about dehydration. In this context, what do you think dehydration means? lacking access to water 2. Astronauts and backpackers often bring dehydrated food. What do you think dehydrated food is? Food without water Gizmo Warm-up What do rice, potatoes, and sugar have in common? They are all foodsrich in carbohydrates . Carbohydrates are an important energy source for your body. The basic building block of most carbohydratecompounds is the molecule glucose . Using the Dehydration Synthesis Gizmo, you will learn about the structure of a glucose molecule and howglucose molecules can be joined together to make larger carbohydratemolecules. To begin, select the CREATE GLUCOSE tab. 1. Look at the chemical formula for glucose. How many carbon (C), hydrogen (H), and oxygen (O) atoms are found in a molecule of glucose? C: 6 H: 12 O: 6 2. Turn on Show chemical structure . Each black sphere represents a carbon, hydrogen, or oxygen atom. The lines connecting the spheres represent chemical bonds. A. How many black spheres are in the diagram? 24 B. How does this relate to the number of carbon, hydrogen, and oxygen atoms in the chemical formula for glucose? one for every dot Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
Activity A: Build a glucosemolecule Get the Gizmo ready: ● Be sure the CREATE GLUCOSE tab is still selected. Introduction: Each element tends to form a certain number of chemical bonds. This value is the valence of the element. For example, a carbon atom has a valence of four. Goal: Construct a molecule of glucose. 1. Identify: The structure of a water molecule (H 2 O) can be written as H-O-H, with each dash representing a chemical bond. Count the number of bonds the oxygen and hydrogen atoms form in a water molecule. A. What is the valence of oxygen? 2 B. What is the valence of hydrogen? 1 2. Build a model: Use the carbon, oxygen, and hydrogen atoms from the Atoms box to build a glucose molecule on the empty hexagon in the building region. Use the chemical structure in the lower right as aguide, and pay attention to the valence of each atom as you build. Once you think you have correctly constructed the glucose molecule, click Check . If necessary, continue to modify your molecule until it is correct. 3. Make a diagram: Congratulations, you have completed a molecule of glucose! Click the Tools tab and click Screen shot ( 📷 ) to take a snapshot of your completed molecule. Right click the image, click Copy , and then paste the image into the box below. Label the image “Glucose.” Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
4. Explain: How did the valence of each element help you determine the structure of the glucose molecule? Only a limited number of additional elements could be joined to each element since eachelement could only have a set number of valence electrons (C=4, O=2, H=1). 5. Make connections: Carbon forms the backbone of every major type of biological molecule, including carbohydrates, fats, proteins, and nucleic acids. How does carbon’s high valence relate to its ability to formthese large and complex biomolecules? When compared to elements like hydrogen and oxygen, carbon can create many more bondssince it has a high valence. Activity B: Dehydrationsynthesis Get the Gizmo ready: ● Select the DEHYDRATION tab. Question: What occurs when two glucose molecules bond? 1. Infer: Glucose is an example of a monosaccharide , the simplest type of carbohydrate. A disaccharide is made from bonding two monosaccharides together. What do you think the prefixes mono- and di- mean? Mono- : one Di- : two 2. Predict: Turn on Show description . Drag both glucose molecules into the building region. Observe the highlighted region. What do you think will happen to the atoms in this region when the glucose moleculesbond? I believe that the atoms will join to create a water molecule, which will then synthesis the twoglucose molecules. 3. Run Gizmo: Click Continue and watch the animation. A. What happened? Maltose was created when two glucose molecules joined after thewater had left the binding site (water molecule separate). B. What was removed from the glucose molecules when they bonded to form maltose? 2 hydrogen atoms, 1 oxygen atom, and water 4. Infer: Based on what you have seen, create a balanced equation for the dehydration synthesis reaction. (Recall that the formula for glucose is C 6 H 12 O 6 .) You will have to determine the formula of maltose yourself. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
Turn on Show current formula/equation to check your answer. 5. Summarize: Use what you have observed to explain what occurs during a dehydration synthesis reaction. Two monosaccharides are combined during dehydration synthesis. A water molecule (H2O) isdrawn out when two monosaccharides interact, resulting in the formation of a disaccharideand water. 6. Apply: A trisaccharide is a carbohydrate made of three monosaccharides. What do you think would be the chemical formula of a trisaccharide made of three bonded glucose molecules? Activity C: Hydrolysis Get the Gizmo ready: ● Select the Hydrolysis tab.● Turn on Show description and Show current formula/equation . Introduction: Carbohydrates made up of three or more bonded monosaccharides are known as polysaccharides . In a reaction known as hydrolysis , your body breaks down polysaccharides into individual monosaccharides that can be used by your cells for energy. Question: What occurs when polysaccharides break up into monosaccharides? 1. Predict: Examine the polysaccharide in the building region and its chemical formula. A. How many monosaccharides can form if this polysaccharide breaks up? 3 B. Recall the formula of glucose is C 6 H 12 O 6 . How many carbon, oxygen, and hydrogen atoms will you need for three glucose molecules? 18 Carbon and Oxygen, 36 Hydrogen C. What must be added to the polysaccharide in the Gizmo to get three glucose molecules? Two water molecules 2. Observe: Turn off Show current formula/equation . Drag a water molecule into the building region. Click Continue . What happened? Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
A glucose molecule disassociated itself from the polysaccharide chain. 3. Infer: Create a balanced equation for the hydrolysis reaction that just occurred. Turn on Show current formula/equation to check your answer. 4. Observe: Turn off Show current formula/equation . Drag the second water molecule into the building region. Click Continue . What happened? the disaccharide broke apart into two monosaccharides 5. Summarize: Now create a balanced equation for that shows the entire hydrolysis reaction. (In other words, the equation should show how the polysaccharide broke up into three separate glucosemolecules.) Turn on Show current formula/equation to check your answer. 6. Compare: How do hydrolysis reactions compare to dehydration synthesis reactions? The opposite of dehydration synthesis is hydrolysis. 7. Apply: Amylose is a polysaccharide that consists of a long single chain of glucose molecules. Consider an amylose molecule with only four glucose molecules. A. How many water molecules are released when the 4-glucose amylose forms? three B. What do you think is the chemical formula for this amylose? C. How many water molecules would be needed to break this amylose down into four glucose molecules? Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
three 8. Extend your thinking: Hydrolysis of the carbohydrates you eat begins in your mouth as you chew. How do you think this process might be affected if a person’s salivary glands were unable toproduce saliva, which is mostly composed of water? Complex carbohydrates cannot be broken down by hydrolysis if salivary water does notinteract with the carbohydrates. Hydrolysis requires water. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
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