Photosynthesis Lesson Plans
The student is expected to recognize that radiant energy from the Sun is transformed into chemical
energy through the process of photosynthesis. Only plants with chlorophyll can make their own energy
from carbon dioxide and sunlight. This process is responsible for all of the energy in the food chain, and
we breathe the waste product in the form of oxygen.
Key Concept 1: The Sun emits radiant energy towards Earth’s surface. Some of this radiant energy is in
the form of light.
•Key Concept 2: Photosynthesis is a chemical reaction that occurs in plants. During this reaction, carbon
dioxide absorbs from the atmosphere and water absorbs from the soil. The chemical energy produced
from the reaction is in the form of sugar also referred to as glucose. Oxygen also produces and releases
into the atmosphere.
•Key Concept 3: The chemical energy or glucose stores in plants, which sustains life on Earth.
TEKS
7.5.A - recognize that radiant energy from the Sun is transformed into chemical energy through the
process of photosynthesis;
7.6.C - recognize how large molecules are broken down into smaller molecules such as carbohydrates
can be broken down into sugars.
7.2.C - learn new language structures, expressions, and basic and academic vocabulary heard during
classroom instruction and interactions;
7.2.I - demonstrate listening comprehension of increasingly complex spoken English by following
directions, retelling or summarizing spoken messages, responding to questions and requests,
collaborating with peers, and taking notes commensurate with content and grade-level needs.
7.4.G - demonstrate comprehension of increasingly complex English by participating in shared reading,
retelling or summarizing material, responding to questions, and taking notes commensurate with
content area and grade level needs;
Lesson Overview
Lesson Objectives:
By the end of this lesson, students should be able to:
• Describe photosynthesis
• Explain where photosynthesis occurs
Overarching Questions:
• How do organisms live, grow, respond to their environment, and reproduce?
Focus Questions:
• How do organisms obtain and use the matter and energy they need to live and grow?
Lesson Questions:
• What is photosynthesis?
• Where does photosynthesis occur?
•What is the Sun’s role in the process of photosynthesis?
•What type of energy conversion occurs during the process of photosynthesis?
•What are the products and reactants in the process of photosynthesis?
•Why is photosynthesis necessary for life on Earth?
•How is photosynthesis observed?
Key Vocabulary
absorb, algae, biotechnology, cellular differentiation, characteristic, chemical, chlorophyll, chloroplast,
energy (organisms), energy transfer, food chain, food web, function, leaf, molecule, nitrogen, nitrogen
cycle, nitrogen cycle, nutrients, pigment, plant, prokaryote, sugar, vacuole
Lesson Outline
Green plants and other photosynthetic organisms form the base for most of the food webs on Earth.
This is because photosynthetic organisms have the ability to store energy from the sun in the form of
sugar. Sugar can be utilized by most organisms for energy, but only photosynthetic organisms can
directly use energy from the sun. Because the energy transfer process is an inefficient one (i.e., energy is
lost to the environment when one organism consumes another), it is important that there be a constant
input of energy into any food chain or food web. That energy is supplied by the sun, and converted for
general use by the photosynthetic organisms of the world.
Photosynthesis requires carbon dioxide, water, and light energy to make glucose. Oxygen and water are
by-products of the photosynthetic reaction. The chemical equation for photosynthesis is described
below:
6CO2 + 6H2O + light → C6H12O6 + 6 O2
Photosynthetic organisms contain a pigment called chlorophyll that allows photosynthesis to occur. In
eukaryotic organisms, like algae and plants, chlorophyll is contained in special cell structures called
chloroplasts.
Common Misconceptions
Students may have the following misconceptions about photosynthesis:
• Students may believe that photosynthesis occurs when plants take carbon dioxide and turn it into
oxygen. While photosynthesis requires carbon dioxide and produces oxygen, oxygen is a byproduct of
the reaction. In fact, photosynthesis produces glucose, which is the end goal for the plant.
• Students may believe that plants perform photosynthesis, and animals perform cellular respiration. In
fact, plants also perform cellular respiration, as after they have stored energy in the form of glucose,
they need to release that energy in order to continue to grow and reproduce.
Prior Knowledge for Students
Students should know that plants require sunlight and water to grow and reproduce. Students should be
aware that there are many different kinds of plants on Earth, in many different environments.
Materials:
• Safety goggles
• Apron
• Protective mitts for handling hot dishes
• Baking dish made of heat-resistant glass
• Hot plate
• Tongs
• Paper towels
• Two large beakers
• Cornstarch
• Spatula
• Lugol’s iodine
• Isopropyl alcohol
• Computer station with projection device
Activate Prior Knowledge
Ask students what the word “producer” means. Students may be able to explain that a producer is an
organism that makes its own food. Have students give examples of producers. Some students may
describe plants, and some students may describe other organisms or objects that make food. At this
point, accept all answers and make note of any misconceptions.
Stimulate Interest
Show students the video segment Nature's Producers (1:34) to introduce them to the importance of
plants in our daily lives. After viewing the video segment, have students write down their ideas about
how plants make their own food. Revisit these ideas as the lesson progresses, clarifying and addressing
any misconceptions.
Finally, post the Essential Questions that constitute what students will be learning. Students may read
them or you may wish to read them aloud together.
• What is photosynthesis?
• Where does photosynthesis occur?
EXPLORE (Guided Inquiry)
Video Segments
•
•
•
Edusmart
Oxygen and Green Plants: The Process of Photosynthesis
Photosynthesis
Reading Passages
• Why Do Plants Need Sunlight?
Directed Inquiry and Guided Inquiry are two alternate instructional pathways through Explore. For
Directed Inquiry, the specific digital resources that students will explore and the order in which students
will explore them are specified for the instructor. In this option, you might choose to present the
specified resources to the entire class, or you may choose to have students individually explore each
resource as you introduce it. For Guided Inquiry, students are given a list of resources to explore on their
own. Your choice between the two should be made based on your students’ level of familiarity with
Guided Inquiry as a process and their need for teacher assistance, as well as on such practical matters as
the number of computers in your classroom. Note that the time estimates in this lesson are based on
Directed Inquiry; a Guided Inquiry session may take longer for students to complete.
Essential Question(s): What is photosynthesis? Where does photosynthesis occur?
Guided Inquiry
Students respond to the essential questions by exploring the Discovery Education resources listed in the
Explore section. Ideally, each student will use more than one resource for information, but no student is
expected to use all of the resources within the time allotted. Encourage students to take notes as they
explore.
If needed, you may want to further guide students by asking more specific questions: What kinds of
organisms can photosynthesize? What does an organism need for photosynthesis to occur? Why is
photosynthesis important?
Circulate among the students as they are exploring and challenge them to summarize for you what they
have learned. Encourage students to use reading, viewing, and note-taking strategies to get the most
out of each resource.
Directed Inquiry
Have students create a t-chart with these labels: “Photosynthetic Structures” and “Photosynthetic
Process.” Show students the video segments Photosynthesisand Oxygen and Green Plants: The Process
of Photosynthesis and have them write appropriate notes in their t-charts. Then review the t-charts with
the class, filling out an “official” t-chart on the board or on a piece of chart paper. Pose the Essential
Questions to the students, and have students perform a think-pair-share to propose initial answers to
the questions.
ELL: After viewing the video segment Oxygen and Green Plants: The Process of Photosynthesis pair
students and ask each to summarize the information presented in the video segment to their partner.
This will allow ELL students to monitor and demonstrate their listening comprehension of the video
segment.
In your review, be sure to highlight and discuss the importance of sunlight to power the chemical
reaction that occurs in the cells of leaves and is mentioned above in the background for teacher,
namely:
6CO2 + 6H2O + light → C6H12O6 + 6 O2
and rewrite the chemical equation in word form also:
carbon dioxide + water + sunlight produces sugar + oxygen
Hands-On Activity
Students will complete the Hands-On Activity Photosynthesis.
Finally, have students work in pairs on the Exploration, Seasons in the Cell. Pass out student worksheets
and have pairs work together to complete the data sheet and write answers to the questions posed on
the worksheet. Gather students together at the end to share their results and to go over answers to
questions. This leads nicely into the Explain segment coming up in the next session.
Revisit students’ written thoughts from the Engage section. Students should work in the same pairs used
for the Exploration to discuss how their initial ideas were correct, or how they should be revised. Have
students summarize what they now know about photosynthesis that they didn’t know before, and share
their summaries with the class.
Finally, as a class, work to summarize responses to the Essential Questions. Have individuals make
suggested answers and allow the rest of the class to make constructive critiques of their answers. Build
consensus about how the answers should be phrased. Seek class approval for the final written answers
to Essential Questions and respond to any remaining questions that students have.
ELABORATE
Have students extend their understanding of photosynthesis and plant evolution by watching the video
segment, Chloroplasts. Then, ask the class: What did the video suggest was the origin of chloroplasts?
(smaller photosynthetic one-celled organisms were incorporated into other organisms; these evolved to
become chloroplasts.) Ask: Why did this occur, do you think? To help students answer this question,
comment on how the video showed two organisms living in a symbiotic relationship. Write the term
“symbiotic relationship” on the board and ask someone to explain what it means based on what they
saw in the video. If necessary, replay the last part of the video (0:56-end). Ask what advantage each
organism gains by being associated with the other. (The protozoan gains a source of food and oxygen;
the algae gains security.) Then go back to discussing the evolution of plant cells and how the
incorporation of small organisms in other larger organisms would confer an advantage to those
organisms, thereby allowing them to be more successful at surviving in their environments. Draw this
out of students through class discussion using leading questions and prompts to allow students to make
these conclusions themselves.
Alternative: Have students apply their understanding of motion to a critical viewing of the Mythbusters
epidsode, MythBusters: Botanical Growth: Talking to Plants
• Challenge students to consider the pseudoscientific idea that it is possible to nurture plants with
soothing words?
• Sharpen students’ understanding of science process by having them critique the Mythbusters’
investigation. Follow the teacher guide to have students use the first worksheet as they observe the
video and record what science investigative skills the Mythbusters use or don’t use. Then students write
out their conclusions on the second worksheet.
Project Ideas: To help your students apply their understanding of the sub-concepts, have students
complete some or all of the following projects. The time required to complete each project will vary;
some may require students to work outside the classroom.
• Have students research the differences between photosynthesis in prokaryotes and photosynthesis in
eukaryotes, and create a presentation of their findings.
• Have students create a poster about the different photosynthetic pigments in plants.
• Have students write a short essay about the fluctuations of chlorophyll in deciduous trees and plants,
and how these fluctuations are related to seasonal conditions.
EVALUATE (20 minutes)
Have students complete the Brief Constructed Response (BCR) item titled Photosynthesis. You may also
wish to assign the online concept assessment and use the results in the student reports to guide you in
assigning any remediation to students.
Review Sheet: Students may review the information in this section using the Photosynthesis Review
Sheet.