Dehydration Synthesis Answer Gizmos

Name: ______________________________________ Date: ________________________ Dehydration Synthesis 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? without water _________________________________________________________________________________ 2. Astronauts and backpackers often bring dehydrated food. What do you think dehydrated food is? Food that has its water removed. _________________________________________________________________________________ Gizmo Warm-up What do rice, potatoes, and sugar have in common? They are all foods rich in carbohydrates. Carbohydrates are an important energy source for your body. The basic building block of most carbohydrate compounds is the molecule glucose. Using the Dehydration Synthesis Gizmo, you will learn about the structure of a glucose molecule and how glucose molecules can be joined together to make larger carbohydrate molecules. 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? 6 12 6 C:_______ H:_______ O:_______ 2. Turn on Show chemical structure. Each black sphere represents a carbon, hydrogen, or oxygen atom. The lines connecting the spheres represent chemical bonds. 24 A. How many black spheres are in the diagram? _______ B. How does this relate to the number of carbon, hydrogen, and oxygen atoms in the chemical formula for glucose? 6 + 12 + 6 = 24 ___________________________________________________________________________ Activity A: Get the Gizmo ready: Build a glucose molecule  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 (H2O) 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. 6 A. What is the valence of oxygen? _______ 1 B. What is the valence of hydrogen? _______ 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 or on the previous page as a guide 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. Congratulations, you have completed a molecule of glucose! 4. Explain: How did the valence of each element help you determine the structure of the glucose molecule? The maximum number of electrons of each orbital minus the valence number tells _________________________________________________________________________________ you how many covalent bonds that atom can have. _________________________________________________________________________________ _________________________________________________________________________________ 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 valence relate to its ability to form these large and complex biomolecules? (Crash Course - Carbon) _________________________________________________________________________________ Carbon's valence# 4 gives it the covalent capability to bond with many different _________________________________________________________________________________ elements which makes it the central atom in the chemistry of life. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ Activity B: Get the Gizmo ready: Dehydration synthesis  Select the DEHYDRATION tab. 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? 1 Mono: _________ 2 Di: _________ 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 molecules bond? A molecule of water will be produced. _________________________________________________________________________________ _________________________________________________________________________________ 3. Run Gizmo: Click Continue and watch the animation. A molecule of water will be produced. A. What happened? _____________________________________________________________ B. What was removed from the glucose molecules when they bonded to form maltose? 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 C6H12O6.) You will have to determine the formula of maltose yourself. C6H1206 + C6H1206 -----> C12H22011 + H2O _________________________________________________________________________________ Turn on Show current formula/equation to check your answer. 5. Explain: Based upon what you observed, what occurs during a dehydration synthesis? Dehydration synthesis is the creation of larger molecules from smaller monomers _________________________________________________________________________________ where a water molecule is released. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 6. The diagram below shows 1 - 4 glycosidic linkages in the formation of a disaccharide from 2 monosaccharides. What are glycosidic linkages and define this terminology in terms of carbon numbering. Glycosidic bond is formed between the carbon-1 of one monosaccharide and _________________________________________________________________________________ carbon-4 of the other monosaccharide. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 7. A trisaccharide is a carbohydrate made of three monosaccharides. What do you think would be the chemical formula of the trisaccharide below made of three bonded glucose molecules? C18H32O16 _________________________ Get the Gizmo ready: Activity C: Hydrolysis  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. What occurs when polysaccharides break up into monosaccharides? 1. Predict: Examine the polysaccharide in the building region and its chemical formula. 3 A. How many monosaccharides can form if this polysaccharide breaks up? ___________ B. Recall the formula of glucose is C6H12O6. How many carbon, oxygen, and hydrogen atoms will you need for three glucose molecules? C = 18 H = 36 O = 18 ___________________________________________________________________________ C. What must be added to the polysaccharide in the Gizmo to get three glucose molecules? water / H2O _________________________________________ 2. Observe: Turn off Show current formula/equation. Drag a water molecule into the building region. One monosaccharide split or broke off from the molecule. Click Continue. What happened? ______________________________________________________ _________________________________________________________________________________ 3. Infer: Create a balanced equation for the hydrolysis reaction that just occurred. C18H36018 + H2O -----> C12H22011 + C6H12O6 _________________________________________________________________________________ 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? ________________________________________________ Another monosaccharide split or broke off from the molecule. _________________________________________________________________________________ 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 glucose molecules.) C18H36018 + 2H2O -----> 3C6H12O6 _________________________________________________________________________________ Turn on Show current formula/equation to check your answer. 6. Compare: How do hydrolysis reactions compare to dehydration synthesis reactions? Dehydration synthesis reactions build molecules up and generally require energy, _________________________________________________________________________________ while hydrolysis reactions break molecules down and generally release energy. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 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. 3 A. How many water molecules are released when the 4-glucose amylose forms? _______ C24H42O21 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? 3 _______ 8. Extend your thinking: A. Hydrolysis of the carbohydrates you eat begins in your mouth as you chew. Why is this? How do you think this process might be affected if a person’s salivary glands were unable to produce saliva, which is mostly composed of water? The digestion of carbohydrates (polysaccharides) begins in the mouth because ______________________________________________________________________________ glucose (monosaccharide) is needed for the CONSTANT production a ATP via ______________________________________________________________________________ cellular respiration. Without water (and enzymes) the hydrolysis of ______________________________________________________________________________ carbohydrates could not occur. ______________________________________________________________________________ B. Why is the hydrolysis of LARGE macromolecules necessary? All living things are made of cells (except viruses) . Cells are small. Raw materials the _____________________________________________________________________________ cell needs to survive must be small in order to pass into the cell via the cell ______________________________________________________________________________ membrane. ______________________________________________________________________________ ______________________________________________________________________________