To conclude the biogeochemical cycle poster project, students each reviewed two posters from groups other than their own. The review consisted of a worksheet with one half containing key items that must be included on each poster for full credit (turned in for participation credit). The lower half of the worksheet included feedback questions that were left with the posters and provided to the groups for feedback. Students then received a take-home quiz consisting of an article about the 2015 Gulf of Mexico dead zone and a quiz with questions connecting the nitrogen, carbon, and water cycles with photosynthesis, cellular respiration, and algal blooms. The quiz is due Monday.
For the next three days, students will learn about leaf structure, photosynthesis, and the connection between photosynthesis and cellular respiration. Students will work in pairs to complete two worksheet packets, and those who finish early will have the opportunity to complete one or more related labs.
For day 1, the entry task called for students to answer (through writing) the following:
- What is photosynthesis?
- Why is photosynthesis important?
- Write the equation for photosynthesis (bonus: include pictures!).
Student work is pictured below:
After the share-out, students watched the Crash Course: Plant Cells video (below) which served as a refresher to plant cells and as an introduction to photosynthesis. After the video, students worked in pairs on the Photosynthesis POGIL worksheet packet.
For Day 2, students reviewed the vocabulary terms of exothermic and endothermic within the context of photosynthesis, cellular respiration, and combustion. Notes from the entry task are pictured below.
After the entry task, we watched the video about photosynthesis by Bozeman Science. Students need to know the first 4.5 minutes of content, but the remaining content (which students wanted to watch) is beyond the scope of our class. After the video, students had the remainder of class time to work on the Photosynthesis POGIL Worksheet Packet from yesterday.
For Day 3, we connected the processes of photosynthesis and cellular respiration first through our entry task and then through a Photosynthesis and Cellular Respiration POGIL worksheet packet. The entry task and white board notes answering the response are pictured below:
For students looking to dig into cellular respiration at the molecular level, the Crash Course and Bozeman Science videos are provided below:
We began class with a discussion of of the reading from yesterday. The discussion focused on helping students understand how to read the questions, how to formulate a response, and the expectation of the quality and depth of thinking expected of a high school student of biology. Notes from the white boards are pictured below:
After the discussion, students conducted an experiment designed to test the effect of exercise on the amount of carbon dioxide exhaled. The experiment introduced students to the concept of cellular respiration (vocabulary they will learn soon) by studying the intersection of the cardiovascular and respiratory body systems. Students measured pH as a surrogate measure of carbon dioxide output by exhaling into a straw placed in a cup of distilled water. To measure pH, students used probeware connected to hand-held computers. They measured the pH of the water before and after exercise, writing down their procedure and optimizing the procedure during the class period. Students obtained data demonstrating a correlation between exhaled carbon dioxide and decreasing pH.
Students wishing to understand the chemistry behind our experiment should visit NOAA’s Ocean Acidification website. The Smithsonian Institute also has an excellent collection of content explaining ocean acidification that includes some videos about how sea life is affected by increasing carbon dioxide in the atmosphere.
We continued our study of combustion with a review of why burning candles lose mass. We watched a video in which Mr. Anderson describes not only the process of combustion but also the concept of Conservation of Mass. At the end of the video, he mentions how neat a candle burning in the space shuttle looks, so I also included a video of the recent FLEX2 experiment aboard the International Space Station. After the lesson, students completed a quiz connecting the concepts of combustion, cellular respiration, and photosynthesis.
The lesson for Monday centered on the concept of combustion. We dove into vocabulary about chemistry and even balanced an equation! We then created a table comparing photosynthesis, cellular respiration, and combustion. Because some classes were ready, we also discussed the combustion of paraffin wax in a burning candle. Yesterday’s lesson can be viewed by clicking here.
Today we held a class discussion focusing on the variables tested in the Baggie Garden experiments. To begin, students considered how their own manipulated variable affected seed germination. We then collected data from each group and used that information to identify temperature as one of the key factors in determining whether a seed will germinate. We also made the observation that seeds in the presence of water at room temperature did germinate, while seeds purchased from the store and kept dry at room temperature do not germinate. Therefore, water is another key factor for seed germination. Finally, we revisited the process of cellular respiration, identifying oxygen as the final requirement for seed germination.
Following the discussion, students had two options for the remainder of the class period. First, they could choose to read about cellular respiration in the textbook (pages 358-359, taking notes on the three stages of cellular respiration). Alternatively, students had the opportunity to build molecules using our new molecular modeling kits. Instructions for both activities can be found in the attached slide deck. Two students successfully modeled glucose, shown both in linear form (below left) and in ring form (below right).
We continued our work modeling cellular respiration, picking up where we left off yesterday. Although 2nd and 3rd periods were shortened because of a fire drill, students in periods 1, 4, and 5 were also able to watch the short video below describing the action of the enzyme ATP synthase. We will have a comprehensive quiz tomorrow covering the topics of body systems, organelles (with heavy emphasis on the cell membrane), and energy.
Today we began learning about how one of the major cellular organelles, the mitochondria, are able to convert glucose into ATP through the process of cellular respiration. We began with a partner share activity, where students discussed their response to the second video segment from Friday with their table partner. One partner wrote a summary of their partner’s response, and then the partners switched. We shared out as a class, discussing the effect of lowering body temperature on catastrophic health events (like heart attacks). We then transitioned to a study of mitochondria, with students sharing what they know about the organelle. We learned the chemical formula for cellular respiration (which occurs in the mitochondria found in both plant and animal cells) by reviewing the process of photosynthesis (which occurs in plant cell chloroplasts). Most students are able to reconstruct the formula for photosynthesis by remembering the key ingredients for plant life:
CO2 + H2O + energy (sunlight) → C6H12O6 (glucose) + O2
Cellular respiration is essentially the reverse of photosynthesis:
C6H12O6 (glucose) + O2 → CO2 + H2O + energy (ATP)
The attached slide deck provides a few additional slides (not presented in class). We connected the idea of cellular respiration back to the second video segment from last Friday to explain why lowering body temperature results in improved health outcomes. Finally, students modeled the process of converting one molecule of glucose to 36 molecules of ATP. The used the molecular structures worksheet along with the instructions to work through part of the activity. We will complete the modeling activity tomorrow and students will write a summary of the process of cellular respiration.