How does your body use food?
This unit explores in more detail the processes by which the nutrients in food become available, and how the body uses them. We will begin with digestion and absorption, and then use biochemistry to understand how the body shuttles energy and nutrients into and out of storage. A major emphasis of this unit is the concept of homeostasis with respect to blood glucose levels. We will see that the body is in a constant quest to make sure that glucose is available, and at adequate levels. We will explore the pathways the body can use to maintain homeostasis of glucose and we will understand the impacts fasting and feasting have on weight loss and weight gain.
Lesson 1
Digestion – From the mouth to the bloodstream
In this lesson we will review and expand on student knowledge of digestion and absorption. The main objective is for students to be able to describe process of digestion in each of the main organs, including select digestive enzymes. They should also be able to compare and contrast digestion and absorption of carbohydrate, fat, and protein rich foods. We also use examples of common digestive problems to illustrate structure-function.
| Objectives | – Describe mechanical and chemical breakdown of food. – Describe the digestion and absorption of macronutrients (carbohydrates, lipids and proteins). – Gain some initial familiarity with the metabolism ring diagram. |
| Activities | Video summary of the journey through the digestive system. |
| Materials | Printed Materials: – In-class worksheet – HW worksheet |
| Homework | Complete a chart that summarizes the major organs and enzymes involved in digest-ing a peanut butter sandwich. |
Lesson 2
Metabolism: How do your cells release energy from food?
In the last lesson we reviewed the mechanisms of digestion and absorption of nutrients. But when the nutrients are absorbed, what are they used for? We need the nutrients in food to make ATP, the major energy currency of all cells. In this lesson we will discuss the process by which ATP is made from sugars and fats by walking students through an interrupted case study about the mitochondria. The concept of energy metabolism is the focus for the next several lessons.
| Objectives | – Explain why we need to maintain glucose homeostasis. – Identify the steps of glucose metabolism and describe what they require and produce. |
| Activities | Dougie’s weight loss interrupted case study, which focuses on ATP synthesis in the mitochondria. |
| Materials | Printed Materials: – Case Study worksheet |
| Homework | Complete questions on the case study worksheet |
Lesson 3
Glucose homeostasis in the blood – The Metabolism Game
In the previous lesson we learned about energy metabolism, which takes place in all cells to make ATP from the macronutrients. We also learned that some organs, particularly the brain, can only use glucose to make ATP. The next two lessons focus on the question: How are glucose levels in the blood regulated? In this lesson students will play a game to learn about the metabolic pathways the body uses to store and un-store energy as glycogen, fat and muscle. Note that for some class- rooms this lesson may take two days to complete.
| Objectives | – Explain where energy is stored after a meal. – Explain how energy comes out of storage during exercise or times of fasting. – Apply metabolism to real-life situations. |
| Activities | Play a Metabolism Game to learn about the processes that maintain glucose homeostasis. |
| Materials | Printed Materials: – Game board, cards – Game instructions – HW worksheet |
| Homework | Complete the worksheet by listing the processes in energy metabolism and storage |
Lesson 4
Glucose homeostasis in the blood (2)
In the previous lesson we learned the metabolic pathways the liver uses to shuttle the energy in nutrients into and out of storage. We will continue to learn about energy metabolism in this lesson by adding more complexity onto the pathways that were presented in Lesson 2.3. Students will also get introduced to the concept of insulin and diabetes in this lesson’s homework.
| Objectives | – Explain where energy is stored after a meal. – Explain how energy comes out of storage during exercise or in times of fasting. – Be able to apply energy metabolism to real-life situations. |
| Activities | Worksheet to apply the metabolic pathways to physiological scenarios of high and low blood glucose. |
| Materials | Printed Materials: – Worksheet |
| Homework | Complete the worksheet. |
Lesson 5
Disorders of metabolism – Where do things go wrong?
In this lesson we will use our knowledge of how the metabolic pathways affect body systems to learn about metabolic disorders. The lesson begins with a discussion about the most prevalent metabolic disorder, diabetes, using last night’s homework. Students will then watch a short video about the hormones glucagon and insulin before doing an activity where they will explore other metabolic disorders. This is intended to link the students new knowledge of metabolism to real life experience, and in the next lesson we will further apply this knowledge to scenarios that challenge homeostasis of body composition.
| Objectives | – Compare and contrast the function of insulin and glucagon in energy metabolism. – List and describe the symptoms, causes and treatments of six different metabolic disorders. |
| Activities | Jigsaw: What happens when the metabolic pathways don’t work normally? |
| Materials | Printed Materials: – Jigsaw readings – In-class worksheet – HW worksheet |
| Homework | Worksheet: Review organ functions in glucose homeostasis and relate them to diabetes. |
Lesson 6
From scrawny to brawny – How metabolism and exercise work together
As in Lesson 4, this lesson relates metabolic pathways to how the body maintains blood glucose homeostasis and builds/burns muscle and fat. To link metabolism to real-life experience we use select scenarios with our characters from a Unit 1 activity, Mimi, Olive, and Edna and we meet a new character, Dougie. In all cases, we use metabolism to define and explain the outcomes of the scenarios and to prescribe lifestyle changes.
| Objectives | – Describe which organs play a role in the regulatory steps of maintaining glucose homeostasis. – Relate the objectives from this unit to fasting, feasting and exercise. |
| Activities | Worksheet: Use metabolic pathways to explain Dougie’s experience and to suggest lifestyle changes. |
| Materials | Printed Materials: – Activity worksheet – HW worksheet |
| Homework | Worksheet: Compare the diets of two professional athletes: a marathon runner and a power lifter. |
Teacher Prep: Unit 2 Lesson Overview Videos
In the YouTube embed below, click the order listing in the upper right to toggle the display for the full playlist.
