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Does anyone have any suggestions for how to teach these two things to high schoolers? I am a little at a loss, especially knowing to what depth I will have to cover them because they are very difficult concepts. I am a biology teacher at Shawnee High School for juniors, which is a PLA school. Do any of you all have lessons that are more activity based? My students are 98% free/reduced lunch, 40% ECE, with more apathy than normal for anything that is mainly note/memorization based. I need to get this through to them, so someone please help!!

Hi Diane. One of the things I do is talk about the difference between plant cells and animal cells. Then, talk about how plants get their energy from the sun and convert CO2 to oxygen. I then talk about how animals get glucose from food such as plants or other animals to support cellular respiration. A neat topic is having them figure out how trees get all that heavy mass from the CO2 they absorb during photosynthesis. Most of them think they suck it out of the ground. Once you get them looking at trees out the window while they're looking out the window, anyway, they are engaged. I teach at an Alternative Education school and if they can associate the lesson with something they can touch, they become engaged. Hope this helps a little...

If you have access to sensors and appropriate software, you might look at several of the labs that Vernier posts on its site in the Biology Manual. There are free sample pdf's of the labs. I will list some websites below. Vernier.com Experiments Biology with Vernier #11A: Cell Respiration (O2) http://www.vernier.com/experiments/bwv/11a/cell_respiration_o2/ Vernier.com Experiments Biology with Vernier #11B: Cell Respiration (CO2) http://www.vernier.com/experiments/bwv/11b/cell_respiration_co2/ Vernier.com Experiments Biology with Vernier #11C: Cell Respiration (Pressure) Vernier.comExperimentsBiology with Vernier #11C: Cell Respiration (Pressure) Vernier.com Experiments Biology with Vernier #11D: Cell Respiration (CO2 and O2) with a video, too http://www.vernier.com/experiments/bwv/11d/cell_respiration_co2_and_o2/ Maybe viewing these procedures will be helpful.

Thanks, Patricia for taking the time to get us these great resources!

Use your state standards as a guide. In my 9th grade biology class we focused on the overall cyclical process and identified the reactants and products. We did a "drawing notes" activity where we drew an illustration of the overall cyclical process. We also did one of the POGIL Cellular Respiration/Photosynthesis packets, which many students found helpful. There are a couple of relatively easy labs you can do if you order the resources in advance (which I didn't). Here's a link to a more advanced lab: http://cibt.bio.cornell.edu/labs_and_activities/images/Elodea.pdf Here's an easier lab: http://kenpitts.net/bio/energy/elodea_lab.htm There's a fun activity where if you put bromothymol blue (I believe) in water and blow into it with a straw, it turns blue! This is because it is an indicator of carbon. The kids might like seeing that reaction. There's a variety of different labs you can modify and differentiate based on your class needs!

I taught these concepts using a guide I received from one of my co-workers. It can be purchased at http://teachinteract.com/c/product.html?nocache@[email protected]+record@TF43373 . This was great because it requires students to compare energy in cells to money in an economy and then complete a puzzle to put together an "energy coin" (a model of a glucose molecule). Then they're required to take it apart to form smaller molecules (carbon dioxide and water) by adding the "circle source" (oxygen). By doing so, they get to see the steps of cellular respiration very clearly. It also has readings that they do, along with assessments to use. I really liked it and would recommend it. It only needs to be purchased once, and then can be reused each year after.

I teach high school too. This semester (my school does the classes in semesters instead of years), I tried something new with photosynthesis. One of my colleagues has a dissolved oxygen meter. My students collected water plants from a nearby lake, and we put them in sealed containers overnight in a growth chamber. We used the DO meter before and after to measure how the dissolved oxygen changed. Theoretically, the DO should have gone up, but some of the students' DO went down - I think some of the containers were not sealed properly. But, that was a good chance for them to learn about experimental procedure and recording errors! I think this helped make the process of photosynthesis more concrete because they could see it happening.

Hi Stefanie. Is there a chance that the humidity in the room caused some of the dissolved oxygen to come out of solution? It might be interesting to take your experiment and use a split cork to put the D.O. probe into the water with the cord of the probe going through the hole in the cork. The humidity in my room is often 25%, so this could affect your readings. just a thought. Great experiment!

Another possibility is that some of the students had leaves that were beginning to decompose. A heavier load of bacteria and fungi could lead to a drop in DO as these microorganisms consumed oxygen from the water in the sealed containers.

Hi Diane - Great questions! These are difficult topics to teach.
I generally teach them as a 'Cellular Energy unit'.

I recommend you check out the free NSTA Science Objects for teacher background content and teaching ideas on
1) Cells and Chemical Reactions: Photosynthesis http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/7/SCB-CCRX.2.1

2)Cells and Chemical Reactions: Cellular Respiration http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/7/SCB-CCRX.3.1

A common student misconception is that only plants do photosynthesis (some animals and bacteria can do photosynthesis) and that only animals do cellular respiration (most living organisms, including plants, do cellular respiration to break down glucose - either aerobic or anaerobic/fermentation).

Of course, there are the fascinating deep sea hydrothermal vent organisms that make their living with chemosynthesis .... a great group to contrast to photosynthesis.

Hi Dorothy. I teach photosynthesis as a key to identifying a producer versus consumer. How do you handle chemosynthesis? I've been teaching chemosynthesis as "producers" but I'm not sure it's clear that chemosynthesis really belongs in the category of "producer." What do you think?

Hi James - Interesting question and potentially a great discussion prompt for students. It is my understanding that those chemosynthetic microbes are the base of the food chain in the deep ocean hydrothermal vent area.... if so, then they would be producers. The microbes are making sugars from chemical compounds, and other organisms then eat the microbes for energy, Here is a quick reference from NOAA on Chemosynthesis http://www.pmel.noaa.gov/eoi/nemo/explorer/concepts/chemosynthesis.html Here is an article comparing Chemosynthesis and Photosynthesis from NOAA Ocean Explorer. http://oceanexplorer.noaa.gov/facts/photochemo.html These are both very short - so could be used for student readings. Dorothy

Hey, thanks, Dorothy. I'm no expert in this area and I really appreciate the links! Thanks again and Happy Holidays! jj

Hi James - I'm no expert either, but am enjoying learning more about this fascinating area of ecology and cellular energetics. Happy Holiday season to you too. Dorothy

Hi Dorothy. I played the links you sent in my classes, today along with some video from Blue Planet and it was a hit! The kids were fascinated with the chemosynthesis topic and we even discussed doing a field trip to Kinzua Dam to check out the iron loving bacteria that grows in a mat near a calix hole in the foundation which drains a geologic structure in the Marcellus Shale area which is rich in methane (natural gas) which could be compared to a cold seep, I think. If the bacteria mat is similar to the bacteria found at the ocean bottom, it would be neat to do a research project at a location accessible by stairs that would be similar to that found at the ocean bottom. I might be totally off the mark on this one, but it would be fun to check it out. Thanks for getting my creative juices flowing!

Diane, One of the activities that we do when a school comes to us for a photosynthesis field trip program at the Chicago Botanic Garden is have the students look at slides of stomata from desert and tropical rainforest leaf samples. We have 6 pothos plants (for the tropical rain forest samples) and 6 jade plants (for the desert samples). That morning, just before the students arrive, we place a strip of clear nail polish on a few underneath sides of leaves (we loosely tie yarn by the leaves we "paint"). Then the students take transparent tape(has to be transparent and not Scotch brand regular tape) and press it against a leaf section coated with the polish. The polish comes off and brings the outer layer of cells with the stomata attached. Students place the tape, sticky side down, on a clean microscope slide and look at the samples under their microscopes. They learn about what molecules in the photosynthesis equation pass through the stomata. They also learn about why desert leaves have fewer stomata than tropical plant leaves. It is a very hands-on way to engage students in a discussion of the both photosynthesis and cellular respiration since the stomata are used for gas exchange in both processes. Carolyn