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Day 37: A. How are photosynthesis + photorespiration different? B. How do the 3 types of plants deal with Hot Sunny Days?
December 19, 2013 at 8:10am


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Sophie Wulfing
January 14, 2014 at 8:43pm

Parent:  Photorespiration doesn't use CO2 but uses O2, which acts as an oxidyzer (duh) and begins breaking down (burns?) sugars as opposed to building them.  Photosynthesis uses CO2 to create sugars.  There are three plant types that deal with hot & sunny weather.  C3 plant opens its stomata during the day and closes at night causing it to save water but reduces CO2 intake.  2)  C4 is partially opened during the day, hides CO2 inside of a bundle sheath so it can use that for photosynthesis while saving water.  3)  CAM which is closed during the day and open at night (the stomata).  Also stores CO2 in an organic acid, thus saving H20 and reduces photorespiration.  Dad:  Why is photo-respiration bad?  Sophie:  Because its not creating energy, it's breaking down the sugars, and the only way plants can supply their energy is to create their own.


After explaining the basic differences between photorespiration and photosynthesis, my dad asked why photorespiratoin was so bad and I had to take a step back and remember why, which is that it takes in the glucose make by the plant, causing a serious loss of energy. Basic rule to remember for plants is that open stomata risk losing water but gaining CO2 and the plants are just trying to balance the losses by opening stomata during the night to reduce dehydration(CAM), partially during the day (C4), or fully during the day for maximum CO2 intake (C3).

Talesh Patel
January 04, 2015 at 1:36pm

Parent:  Photosynthesis uses Carbon Dioxide to create energy (sugars) while Photoresperiation consumes Oxygen to do the same thing but is less efficient.

The three different types of plants C3, C4 and CAM react very differntly during hot days. All plants have a Stoma, which acts like a mouth, the CAM plants have a closed stomata during the day when the weather is super hot and open up during the cooler nights.  The C3 and C4 plants a have open or partially open stoma during the hotter days to create energy.Student: Photosynthesis and Photorespiration are different in that photosynthesis uses CO2, H2O and light energy to create sugars that the plant can use. This processes occurs in the chloroplasts of the plant. Photorespiration uses O2 instead of CO2 and Rubisco to create G3P, half of a glucose. This reaction gives off CO2 and can be harmful to the environment. CAM plants, C4, and C3 plants all deal with hot sunny days differently. CAM plants have closed stomata, a mouth like opening on plants, during the day. But during the night, they open up to perform cellular respiration. This prevents the evaporation of water during the day but allows these plants, such as cacti, to still create energy. C4 and C3 plants, create different carbon compounds as their names describe. C3's make up most of the plants that surround us. In cool, moist climates they are more efficient then C4 and CAM plants, but lose water very quickly if condition heat up. C4 plants are better at photosynthesis then C3 plants because the CO2 is delivered to Rubisco directly preventing Photorespiration. This topic was a little tough to cover because my notes and the book were a bit different. When researching online, my notes were correct and I had to re-explain everything to my dad, who was confused.

Anne Sweeney
January 04, 2016 at 10:35pm

Parent: Anne explained the difference between Photosynthesis which CO2 is taken in and the end result is sugar, and Photorespiration which CO2 is not taken in which the end result is the breakdown of sugar and uses all its ATP.  Also I learned about the different plants and how they open or close their stomata in order to store CO2 in order to save water and increase photosynthesis. So now I know what my flowers are doing when they close at night.

Student: I explained that the difference between Photosynthesis and Photorespiration are the presence and absence of CO2, which can cause drastic changes to the processes. It helped to take each cycle step by step and explain the cause of each step, instead of just listing the product. While explaining the C3, C4 and the CAM I first taught my mom about the stomata ‘stoma’  and used an analogy, ‘little mouths’ on the plant that intake CO2 to start the process needed. I also referred to the textbook pictures so my mom could visualize the processes taking place. CAM plants makes more sense to me now because of its explanatory name Crassulacean acid metabolism; the organic acid that CO2 is stored as to save for the calvin cycle.

Makaila Heifner
January 05, 2016 at 10:39am

Parent: Makaila explained to me that photo-respiration is a process that breaks down the sugars made by photosynthesis and explained that this is bad for plants. When I asked why she explained that it breaks down energy that the plant could have used elsewhere. We also went over the 3 different kind of plants, which I found interesting because I didn't know there were 3 different kinds - I only thought there were different species of plants.

Student: I went over the difference between photosynthesis (uses CO2) and photo-respiration (uses O2) and explained why it is bad when a plant goes through photo-respiration. I find this topic interesting because I wouldn't have thought that taking in O2 would be bad for a plant since it produces oxygen. I also found it useful to go over the three different kinds of plants (C3, C4, and CAM). I explained how each type uses their stomata differently and how that effected the plant. 

Lauren Masters
January 05, 2016 at 8:39pm

Parent: Lauren explained that photosynthesis and photorespiration are somewhat opposites. Photosynthesis takes in CO2 converts to energy and allows the plant to live. Photorespiration only takes in O2 which causes sugar break down and the plant dies. She also talked about the three types of plants, C3PO (haha) C3 such as leaves have open stomata during the day and closed at night and preform their photosynthesis during the day. C4, like grass, are partially open during the day and closed at night. They store CO2 for photosynthesis during the night. CAM, such as cactus, are closed during the day and open at night and save CO2 for photosynthesis at night.

Lauren: I found this topic very easy to explain to my mom. She seemed to understand the difference between photosynthesis and photorespiration very well. Photosynthesis takes in CO2 and produces O2 whereas in photorespiration O2 is taken in and it builds up, all the ATP and NADPH is used up and the plant dies. She found it interesting how the plants are able to do photosynthesis at night. C4 plants hide CO2 in a bundle sheath as a 4 carbon organic acid in order to do this. CAM plants also save CO2 as an organic acid.

Darci Kudrna
January 05, 2016 at 8:46pm

Parent:  What I learned about plants and how they use oxygen and carbon dioxide was that there are 3 types of plants.  The first type (C3) has a stomata that stays open during the day to take in as much CO2 as possible.  It is much like having its mouth open.  This allows it to take in CO2 but also uses loses much of its H2O when it does so.  The second type, (C4) only remains partially open during the day.  These are plants such as corn and grass.  This allows it to stay hydrated.  It also has a way to store some of its energy so that it can use it when needed. The third type (CAM) are plants that are typically in desert environments.  Because the heat would dehydrate the plant, if the stomata stayed open during the day, it closes during the day and opens during the night so that it can take it the CO2 during the night without losing all of its H20.


While explaining the difference between photosynthesis and photorespiration my mom wondered why the plant would use oxygen even though it would cause harm to the plant, so I explained that the charges of CO2 and 02 are close enough that receptors are unable to tell the difference between the two so they use oxygen in replacement of carbon dioxide.

Benjamin Niesner
January 05, 2016 at 9:30pm

Student: I explained to my Mom that Photosynthesis is good for the plant because it allows the proper amount of CO2 to be brought into the Calvin Cycle which leads to the making of G3P. I told her that the opposite of photosynthesis is photorespiration which is very bad for the plant. This is similar to a human not breathing and choking to death. photorespiration doesn't allow any CO2 into the Calvin Cycle which uses up its ATP and NADPH while breaking the sugar needed. I also explained the three ways to decrease photorespiration with the C3, C4, and CAM plants. These plants all have to adapt to different environments opening and closing their stomatas according to sunlight, heat, etc. C4 and CAM plants are the best at decreasing photorespiration. 

Parent: I learned the difference between photosynthesis & photorespriation, as well as the different types of plants & how they process CO2 and survive the elements in their environments. I didn't realize that some plants shut down their ability to absorb CO2 in extreme conditions. I suppose that's why my grass turns brown in the summer. :)

Sarah Kropelnicki
January 27, 2019 at 9:12pm

Parent: I learned about the 3 different types of plants from Sarah today, and how while photosynthesis is good because it takes in carbon dioxide, ATP, and NADPH, photorespiration is harmful because it takes in O2 instead and breaks the sugars instead of making them like photosynthesis. 

Student: I taught my dad about C3, C4, and CAM plants. I really liked this ETD because plants are amazing! The ideal plant situation is the CAM plants (like cacti) because they close their stomata mouth in  the daytime and open it in the night time. This helps them to save water, increase their intake of CO2 which in part increases photosynthesis, and decreases photorespiration. 

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