Embedded Files
Chapter 26
Nutrition And Metabolism
Topic of lesson
Lipid Metabolism: This includes the breakdown of fatty acids to generate energy and the synthesis of new lipids from smaller molecules to store energy. These fats come from food that people eat every day, or are synthesized by the liver.
Learning objectives
At the end of the lesson, the student should be able to
- describe the processes of lipid catabolism;
- describe the processes of lipid anabolism.
Pre-assignment
Watch the video: Metabolism & Nutrition, part 1: Crash Course A&P #36
Activity
- Teacher prepares two plates of white liquid, one is milk and the other one is potato starch dissolved in water. However, students don't know the difference at the beginning.
- Add food coloring to both liquids and then add a drop of dish soap to each one. The colors in the milk start to mix rapidly while the colors in the starch don't change much.
- Students brainstorm why the reactions are different. They should realize the two types of white liquid contain different particles. Milk contains lipids while starch doesn't. It is the breakdown of lipids causing the mixing of the colors.
- Breaking down fat for fuel inside our body is called lipolysis. It begins with the hydrolysis of a triglyceride into glycerol and fatty acids. Triglycerides are the main constituents of body fat in humans and other animals.
- From then on the glycerol and fatty acids are further oxidized by separate pathways. Teacher shows the diagram of Lipolysis and Lipogenesis Pathways.
- Glycerol is easily converted to PGAL and thus enters the pathway of glycolysis. Quickly review what they have learned in the previous lessons about Carbohydrate Metabolism.
- The fatty acid component is catabolized in the mitochondrial matrix by a process called beta oxidation, which removes 2 carbon atoms at a time.
- Lipogenesis employs compounds such as sugars and amino acids to synthesize glycerol and fatty acids. The glycerol and fatty acids can then be condensed to form a triglyceride, which can be stored in the adipose tissue or converted to other lipids.
- Students work in group to use the molecular model sets to build models of different compounds during the Lipid Metabolism. Take pictures of the models and then make a flowchart using PowerPoint to demonstrate the process.
Resources
- Science notebook for taking notes
- Plates, milk, starch, food coloring, dish soap for demonstrate the experiment
- Molecular model sets for students to make the models
- iPads for taking pictures and making flowcharts
Alignment with NGSS
Disciplinary Core Ideas
- LS1.C: Organization for Matter and Energy Flow in Organisms
- Lipogenesis employs compounds such as sugars and amino acids to synthesize glycerol and fatty acids. The glycerol and fatty acids can then be condensed to form a triglyceride, which can be stored in the adipose tissue or converted to other lipids. As matter and energy flow through different organizational levels of living systems, chemical elements are recombined in different ways to form different products. (HS-LS1-6),(HS-LS1-7)
- Breaking down fat for fuel inside our body is called lipolysis. It begins with the hydrolysis of a triglyceride into glycerol and fatty acids. Glycerol is easily converted to PGAL and thus enters the pathway of glycolysis. The fatty acid component is catabolized in the mitochondrial matrix by a process called beta oxidation. As a result of these chemical reactions, energy is transferred from one system of interacting molecules to another. Cellular respiration is a chemical process in which the bonds of food molecules and oxygen molecules are broken and new compounds are formed that can transport energy to muscles. Cellular respiration also releases the energy needed to maintain body temperature despite ongoing energy transfer to the surrounding environment. (HS-LS1-7)
Science and Engineering Practices
- Developing and Using Models
- Students work in group to use the molecular model sets to build models of different compounds during the lipid metabolism. Use a model based on evidence to illustrate the relationships between systems or between components of a system. (HS-LS1-5),(HS-LS1-7)
Crosscutting Concepts
- Systems and System Models
- Take pictures of the compound models and then make a flowchart using PowerPoint to demonstrate the process. Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions—including energy, matter, and information flows—within and between systems at different scales. (HS-LS2-5)
- Energy and Matter
- Lipid metabolism includes the breakdown of fatty acids to generate energy and the synthesis of new lipids from smaller molecules to store energy. Changes of energy and matter in a system can be described in terms of energy and matter flows into, out of, and within that system. (HS-LS1-5), (HS-LS1-6)
- These fats come from food that people eat every day, or are synthesized by the liver. Energy cannot be created or destroyed—it only moves between one place and another place, between objects and/or fields, or between systems. (HS-LS1-7),(HS-LS2-4)
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