Photosynthesis

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Objective

SWBAT identify the reactants and products for photosynthesis as well as describe how the reaction occurs.

Big Idea

Use this lesson about photosynthesis to address chemistry and biology concepts.

Engage

5 minutes

As the students enter the room, they take out their journals and respond to the prompt:

What is photosynthesis?  

While the students work, I circulate through the room reading their responses.  Doing this gives me a better idea of their initial understanding of the topic, so  I am more able to guide discussion during the lesson.  This student journal shows that students have a basic understanding of the topic, so this lesson dealing with exploring chemical processes will help them examine photosynthesis at a deeper level.

Once the students have had an opportunity to respond, I lead a class discussion asking the students to share their written responses.  I ask the students to build upon the answers of their classmates and to provide as much detail as possible.  The students are able to list several of the structures in the leaves of plants and describe the basic input and output of photosynthesis.

Explain

20 minutes

After reviewing the students' journal responses, I tell the students they will again be practicing taking notes from a text and I have the students access the online version of the photosynthesis worksheet. For this specific activity we use the 2000 edition of the Prentice Hall Science Explorer series.  Information about cellular respiration written at the student level can also be found on the BBC Bitesize website.

We review the key steps of taking notes while reading.  For most of my class sections, I have the students use their textbooks to take notes, though they may use the website at home to take notes.  For some of the class sections, I read through the text with the students and have them fill in the information as we go paragraph by paragraph.  For other sections of the course, I give the students fifteen minutes to work on their own and then we go over the information they filled in.

This note taking process addresses SP2 (Developing and Using Models) as students review visual models for photosynthesis and NGSS MS-LS1-7 as students review the manner in which cells produce energy through photosynthesis.

Explore

15 minutes

Once the students have finished their notes, we review the basic information as a class, paying specific attention to the chemistry aspect of the process. For instance, we review the chemical equation for photosynthesis and examine the chemical equation in relation to cellular respiration.

The students then spend time working on parts two and three of the photosynthesis worksheet.  These sections require the use of the Chromebooks as the students review online interactives related to photosynthesis.  On the BioMan Photosynthesis Interactive, students explore the various leaf structures involved in the process of photosynthesis.  This also addresses SP2 as students examine models.

On the third section of the worksheet, students use the BioMan Photosynthesis and Respiration Game to examine the processes of photosynthesis and cellular respiration.  This website also helps to reinforce the use of the chemical equations for photosynthesis and cellular respiration.  

The students work independently on parts two and three of the activity.  While they are working, I spend time meeting with individual students.  During these meetings, I address the students' misconceptions regarding cells, specifically issues they are having with understanding the functions of the various organelles.  Some of the students confuse the lysosomes with vacuoles, so I work with them to develop their own method to remember the differences between the two.

In this student work sample, the student answers most of the questions correctly but has inserted zeros in the equation for photosynthesis.  In this case, I met with the student to review why she had done this and explained that neither zeros nor ones are to be used as coefficients in chemical equations.

This video provides more information about the interactives being used.

Wrap up

2 minutes

Near the end of class, I have the students put their Chromebooks away and I lead a quick review discussion.  I ask a student to explain how chemistry plays a role in photosynthesis.  By asking this question, I am looking for the students to provide a response including the reactants and products of photosynthesis.  I am also looking for the students to be able to describe the general structures of plants that are involved in the process of photosynthesis.  I then ask the students to describe similarities and differences between photosynthesis and cellular respiration.  I expect them to include information about the chemical equations for each process in the discussion.