Photosynthesis and Cellular Respiration
Objective
Big Idea
Introduction
In this lesson students review their knowledge about Photosynthesis and Cellular Respiration, particularly how energy plays a role in these processes.
This is a topic that I have not taught in previous years, but with NGSS my district decided that this would be an appropriate topic to review with students during the unit on Energy. Before teaching this lesson I spoke with the Biology teachers about how they teach Photosynthesis and Cellular Respiration. For the most part the teachers at my school talk about these topics and do discuss the chemical reactions with students. Therefore, I decided that this would mostly be a review lesson for students but would be a great way for them to reflect back on something that they already learned and hopefully see how it makes more sense now that they have learned about molecules, chemical reactions, and energy.
- This lesson aligns with the Next Generation Performance Expectations of HS-LS-1-5 Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy and HS-LS-1-7 use a model to illustrate that cellular respiration is a chemical process whereby the bonds of food molecules and oxygen molecules are broken and the bonds in new compounds are formed resulting in a net transfer of energy. This lesson aligns with these standards PE's because it deals with the processes of photosynthesis and cellular respiration.
- This lesson aligns with the Next Generation Crosscutting Concept 5: Energy and matter. It does so because students are working with the concept of energy and how it relates to photosynthesis and cellular respiration.
- This lesson aligns with the NGSS Science and Engineering Practice 6: Constructing Explanations: It does so because students are expected to explain the differences between photosynthesis and cellular respiration.
- This lesson also aligns with the NGSS Science and Engineering Practice 2: Developing and Using Models: It does so because students are using models to differentiate between the two processes.
For this lesson students need access to computers or tablets to do the activities.
Engage
Because this lesson is a review of what students should already know from Biology I give students a chance to think about what they already know about photosynthesis and cellular respiration before the lesson.
To do this I simply tell students,
"Today we are going to be learning about photosynthesis and cellular respiration. I know that these are processes that many of you have already learned about in Biology. Take a minute and think to yourself what you remember about these processes."
After giving students a minute to think I then tell students,
"Now turn to the people in your table groups and share with them what you already know about these processes."
As students are discussing with their partners I walk around and listen to their responses. Some examples of what I hear include:
-"I don't remember"
- "Photosynthesis is what plants do and cellular respiration is what people do"
- "Photosynthesis is where plants make food with sun"
- "I think they are like opposites"
Explain
For this section of the lesson I introduce the computer activity to students. For more information on how I use computers in my classroom see my reflection on computer use in the classroom in my Introduction to Energy lesson.
- I begin by passing out the photosynthesis and cellular respiration computer activity paper.
- I then tell students that they will be going up to their computers with their table groups to complete the two activities.
- I tell them how they are on two different websites that are saved in the bookmarks folder but that should come up when they start typing in the url as well.
- I remind them that the goal of the computer activities is to refresh their memory of photosynthesis and cellular respiration from Biology class and to see how energy plays a role in these processes.
- Finally I stress that they are working with their groups so should all be participating and that they should be writing their answers in their own words.
Elaborate
In this section of the lesson students are performing their computer activities with their groups on their photosynthesis and cellular respiration computer activity paper.
They begin by going to the first website for NOVA where they explore photosynthesis including the cycling of molecules and the equation. As they do this activity they fill in answers on their worksheet. This is an example of what students should be writing.
After students complete the NOVA activity I have them go to the Sumanas website where they explore cellular respiration and then compare cellular respiration to photosynthesis. As they do the activity they fill in their answers on their worksheet. This is an example of one student's responses.
Overall these two activities were fairly straightforward to students. The biggest issue that students had was making sure that when they compared photosynthesis and cellular respiration on the last part of the activity that they included at least three points.
Evaluate
To evaluate and reinforce these ideas I had student perform a bookwork study guide paper for homework. In my classroom I use Glencoe's Chemistry: Matter and Change section 24.5 on metabolism.
I find that this is a good way for students to review what they learned in class regarding the processes and give a little bit of extra reinforcement of the terms.
I stamp the homework for completion at the next class and go over the answers.
For you classroom you can have students read a section in their textbook or you can also have them do an online practice quiz such as this quizlet or read an online textbook such as this one by an L.A. Unified School District teacher.
