Question

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 to ten bonded monosaccharides are known as oligosaccharides. in a reaction known as hydrolysis, your body breaks down oligosaccharides into individual monosaccharides that can be used by your cells for energy.
question: how do oligosaccharides break up into monosaccharides?

1. predict: examine the oligosaccharide in the building region and its chemical formula

a. how many monosaccharides can form if this oligosaccharide breaks up?
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b. recall the formula of glucose is c₆h₁₂o₆. how many carbon, oxygen, and hydrogen atoms will you need for three glucose molecules?
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c. what must be added to the oligosaccharide in the gizmo to get three glucose molecules?
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1. observe: turn off show current formula/equation. drag a water molecule into the building region. click continue. what happened?

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1. infer: create a balanced equation for the hydrolysis reaction that just occurred.

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turn on show current formula/equation to check your answer.

1. observe: turn off show current formula/equation. drag the second water molecule into the building region. click continue. what happened?

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(activity c continued on next page)

Explanation:

Step1: Analyze monosaccharide - formation

The number of monosaccharides formed depends on the number of sugar - units in the oligosaccharide. Since oligosaccharides are made of 3 - 10 monosaccharides, without seeing the specific oligosaccharide, we assume based on the context of getting 3 glucose molecules later. If we want 3 glucose molecules, 3 monosaccharides can form.

Step2: Calculate atoms in glucose

The formula of glucose is $C_6H_{12}O_6$. For 3 glucose molecules, carbon atoms: $3\times6 = 18$, hydrogen atoms: $3\times12 = 36$, oxygen atoms: $3\times6 = 18$.

Step3: Determine what to add

To break an oligosaccharide into monosaccharides (in this case glucose), water molecules are added in a hydrolysis reaction. So water ($H_2O$) must be added.

Step4: Observe water - addition effect

When a water molecule is added to the oligosaccharide in the hydrolysis reaction, the oligosaccharide starts to break down into smaller sugar units.

Step5: Write hydrolysis equation

Let the oligosaccharide be $C_{18}H_{32}O_{16}$ (a common trisaccharide formula, for example). The hydrolysis reaction with 2 water molecules to form 3 glucose ($C_6H_{12}O_6$) molecules is $C_{18}H_{32}O_{16}+2H_2O
ightarrow3C_6H_{12}O_6$. When a second water molecule is added, the oligosaccharide further breaks down until it forms 3 glucose molecules.

Answer:

1.
A. 3
B. 18 carbon atoms, 36 hydrogen atoms, 18 oxygen atoms
C. Water ($H_2O$)

1. The oligosaccharide starts to break down into smaller sugar - units.
2. $C_{18}H_{32}O_{16}+2H_2O

ightarrow3C_6H_{12}O_6$ (assuming the oligosaccharide is a trisaccharide with formula $C_{18}H_{32}O_{16}$)

1. The oligosaccharide continues to break down until it forms 3 glucose molecules.