Mitochondria "The Powerhouse of the Cell"
Lesson 4 of 5
Objective: SWBAT describe process that produce energy in mitochondria for cellular activity.
Engagement of students begins with a digestive system animation. This animation is a good way to either introduce the journey that food takes in our bodies, or it can be a review if you have already have covered the digestive system in a prior unit. The reason I show students this animation is to frame a real life application for cellular respiration. Creating the link between food, digestion, and cellular respiration is important in order to create relevance to a concept that is very abstract.
I particularly focus on the small intestine when I show this animation, since it is here where nutrients are removed from blood stream. Asking students to predict where the nutrients (i.e. sugars) will go next is a good tie in to the mitochondria and cellular respiration.
The focus question can be, "Why do we eat?" The obvious answer is to get energy, but I emphasize to students it doesn't just happen. Where is that energy created? This is where mitochondria comes into play.
In order for students to explore and most importantly observe cellular respiration and fermentation (anaerobic respiration) I have students investigate cellular respiration in yeast. Yeast are a great model organism in cellular biology (SP2).
I hand students Investigating Fermentation (courtesy of www.shellyssciencespot.com) and Cellular Respiration in Yeast Demo (courtesy http://science-class.net) during the same class period, which complement each other nicely. (More on that below.)
Investigating Fermentation introduces students to fermentation and its real world applications (alcohol, bread, yogurt, cheese). This lab requires you to have water bottles, sugar cubes, warm water, balloons, and yeast.
The Cellular Respiration in Yeast Demo discusses cellular respiration emphasizing important vocabulary words such as energy, respiration, mitochondrion, and it includes the cellular respiration equation.
As students work I walk around groups and ask students some probing questions such as:
1. Can you predict the outcome of the water bottle that is not receiving sugar?
2. How is this lab related to cellular respiration?
3. What's so special about yeast? Why are they considered a model organism?
4. What would happen if we didn't use warm water?
I assess student learning by having students complete both handouts.
In this part of lesson I have students visit cK-12 Cellular Respiration website. On this site students read a text on cellular respiration and watch a video that further explains respiration. I provide students with Cellular Respiration Reading Pre and Post Read to interact with text.
The objective of the reading strategy is to have students predict the main ideas of the text based on context clues, to generate questions about a given topic, and to organize and review the knowledge learned about the topic using the SQ3R strategy.
To evaluate our progress toward the lesson objective I have students complete a Multi-Flow Map. A multi-flow map is used to show the relationship between events, it's a great map for cause and effect. I'm assessing to see if students understand in particular what is the cause and effect of cellular respiration (i.e. glucose + oxygen ->carbon dioxide + water + energy).
I introduce a multi-flow map by using a recipe as an example (ingredients -> product). For example the ingredients to make a bake (flour, eggs, water) > go to oven > baked cake.
Depending on class I may provide a word bank (water, glucose, oxygen, carbon dioxide, ATP, mitochondria) which students need to put into a multi-flow map.
This flow map can then be used as a reference for a future writing assignment where students are required to write an explanatory text describing cellular respiration using evidence from multiple sources (text, lab, video) (W.7.2).