Lesson 7 of 11
Objective: SWBAT create a model of the dehydration synthesis chemical reaction and develop a detailed narration to describe this process.
This video clip serves as an introduction for the lesson and will focus on the importance of carbon, hydrogen, and oxygen forming chemical compounds to create different carbohydrate molecules.
Students watch the Organic Molecules video and record notes. I encourage them to focus their notes on details describing the molecular structure and real world example for each of the three types of carbohydrates - monosaccharides, disaccharides, and polysaccharides.
The video is very heavy in biological details, so many students may feel overwhelmed by its content. Students should focus their notes on the following concepts:
- Elements that compose carbohydrates
- General formula for carbohydrates (sugars)
- Types of carbohydrates and one example of each
- Function of carbohydrates in everyday life
The students review their facts at the conclusion of the video in a pair-share activity.
Using the lecture notes and the data from the previous laboratory activity, students create drawings to represent models of the three common categories of carbohydrates that were tested in the laboratory activity. The illustrated models need to depict each of the following: monosaccharides, disaccharides, and polysaccharides.
Students also develop a narration that EXPLAINS the chemical reaction that has occurred to allow each of the three categories of carbohydrates to form.
Students need to include the following information for each of their three cards:
- Front of the Card - Draw the structural model on the front
- Back of the Card - Identify a common/household example of this type of carbohydrate
- Back of the Card - Write the narration of the chemical reaction that occurred to create this type of carbohydrate.
These cards will be used in the next portion of this lesson
Samples of Students' Work: CHO Trading Cards - Students are able to recreate the image of each category of carbohydrate by using the image in the textbook as a model. The most valuable aspect of this activity is for students to describe the chemical process that must occur to allow disaccharides and polysaccharides to form. Students are able to relate this lesson to their real lives through the identification of common carbohydrates that represented each of the three categories.
Image of CHO Playing Cards - The male students really enjoy creating these carbohydrate trading cards due to their likeness to baseball cards. The image of the carbohydrate was on the front and it is stressed that the picture should reflect the molecule like it was the star of the show, like a baseball card. The back of the cards provides the "statistics" of the carbohydrate by describing how it was formed and listed common everyday examples.
Once the students complete work on their Carbohydrate Trading Cards, I ask for student volunteers to read the narration on the back of the cards that describe the process of chemically combining monosaccharides to form disaccharides and polysaccharides. I follow the directions the student-volunteer gives and try to create the polymer based on the student's verbal direction. Most students realize that their narrations need to be more specific and are given an opportunity to edit/revise their Carbohydrate Trading Cards.
After revisions have been made, students exchange the final draft of their creations with the person sitting behind them. Students review their partner's work for accuracy of the model diagram on the front of the card and attention to detail in the narration of the chemical reaction.
I ask for student volunteers to teach the class about their category of carbohydrate. They must provide the name of the common carbohydrate example and describe the chemical reaction that occurred during its formation.
As a final review of carbohydrates, the students get out a sheet of paper and title it, "My One-Minute Report". They have one minute to "brain-dump" everything they know about carbohydrates, their structure, the chemical reactions to form polysaccharides, their use in our everyday life and in our body.
After one minute, students get into their 4-person lab groups and switch papers with one person to their left. They have two minutes to read their peer's paper and add as many facts as they can to it. Students must be careful to only write in facts that they are certain are accurate and true since this paper will be used as a study guide for the upcoming assessment.
After two minutes, students switch one more time by passing their current paper to the left and repeat the process of adding any missing details on to their partner paper. The group switches for a third and final time and go through the same revision process. After two minutes, the students will switch again and the paper should be back to its original author.
Students are encouraged to review their edited document and the group will have 3 minutes to discuss the additional facts that were added to their paper. These collaborative documents will be used to prepare for the upcoming quiz.
Sample of Student Work: Carbohydrate Brain Dump- This specific student was able to record their understanding of carbohydrates, but ran out of time to switch papers with their neighbors to build a compilation of carbohydrate facts.