7 Cells

By Daniell DiFrancesca

Provided by Kenan Fellows Program.

This lesson introduces students to organelles, cells, and characteristics of the kingdoms. Students will begin their investigation at the organelle level and work up to the kingdom level. After students have created a study guide to cells, they will plan and complete an experiment to increase their knowledge and experience. This lesson is written using the 5E learning model, which includes five phases: engage, explore, explain, elaborate, and evaluate.

Learning outcomes

• Students will define the structure and function of each cell organelle.
• Students will identify organelles in cell samples.
• Students will use cell samples to identify major characteristics of the kingdoms.
• Students will organize observations to create a study guide.
• Students will increase their inquiry skills.
• Students will use experimental data to make conclusions.
• Students will present their finding to the class.

Teacher planning

Time required

Approximately 280 minutes, divided as described below. Students can also complete some of the research on their own to decrease the time needed in the classroom.

Materials needed

• microscopes (1 microscope for every two students is best)
• various slides from the Animal, Plant, Fungi, Bacteria, and Protista Kingdoms
• electron microscope images of cell organelles

Student handouts

Research materials

• internet, books, encyclopedias, articles, text book, etc.
• grids for cell counting (print small grids on overhead transparency sheets and cut into small sections for the students)
• green algae from outdoor water sample or aquarium store
• Petri dishes for algae growth (determine how many each group needs)
• substances to adjust pH for students
• pH paper to determine pH and monitor
• slides and cover-slips for wet mounts
• graph paper
• large paper for posters (if necessary)

Technology resources

• overhead projector
• computers with internet access if possible

Pre-activities

Before conducting this lesson, the teacher should find electron microscope images of the following organelles. Many images can be found by searching the internet with Google and checking the image results. Images can also be found in your science textbooks and reference works. Make enough copies of these images for each student. Ensure they are small enough to fit in the squares on the organelle chart.

• nucleus
• mitochondria
• chloroplast
• golgi body/apparatus
• cell wall
• cell membrane
• lysosome
• endoplasmic reticulum
• ribosome
• vacuole
• vesicle
• cytoplasm

Students should be introduced to proper microscope use and techniques. They should also understand the importance of scientific drawings and their accuracy.

Activities

Engage

What are cells?

(Time: 20 minutes)

1. Assess prior knowledge: Ask the students to describe cells, give examples of cells, and draw a picture of a cell in their notebooks.
2. Students should then pair up with their neighbors and compare their answers.
3. As a class, share student ideas on cells.

Explore

Cells have organelles

(Time: 50 minutes)

1. The students will begin by looking at the cell organelles.
2. Give each student six copies of the organelle chart worksheet or three copies printed on both the front and back. Each student should also receive a small, printed electron microscope image for each organelle.
3. Discuss what an electron microscope is and why it is important to use this tool when studying the structure of an organelle.
4. Students should complete each organelle chart by:
   • Writing the name of the organelle at the top of the section
   • Describing the function of the organelle in the provided space
   • Pasting the organelle image in the square provided for the electron microscope image
   • Drawing the organelle
5. In order for students to accurately complete the organelle pages you can choose to do the following:
   • Create a PowerPoint of the cell organelle functions, electron microscope images, and drawings to use with the class.
   • Provide the students access to computers to research these things on their own.
   • Provide the students with appropriate research materials (books, articles, etc.) to find the answers.

   The students will complete the charts after viewing cell samples and determining the characteristics of the kingdoms.

Organelle function overview

(Time: 20 minutes)

1. Students will complete the organelle function checklist to more clearly define the role of these organelles in the cell.

Organelles in cells

(Time: 2 class periods about 50 minutes each)

1. The students will use the microscope to view various cell samples and identify the visible organelles.
2. Each sample will be drawn under low power for cell to cell structure and high power for cell detail including organelles.
3. Students should color their drawings and label the important details.
4. Students will identify the organelles that were visible.
5. You will need to help the students identify the organelles that were present but not visible with the microscope.
6. Students should be provided with two samples from each of the following kingdoms: Animal, Plant, Fungi, and Bacteria. Tell students which samples belong to which kingdom.

Explain

Using cells samples to define kingdom characteristics

(Time: 30 minutes)

1. Students will use their cell level charts to characterize the Animal, Plant, Fungi, and Bacteria Kingdoms.
2. Students will complete the kingdom summary chart for these four kingdoms.

Option 1: Why are Archaebacteria in a separate kingdom?

(Time: 20 minutes)

1. Ask students to research the defining characteristics of this kingdom and determine why it is its own kingdom.

Option 2: What is the Protista kingdom?

(Time: 40 minutes)

1. Introduce students to several examples of members of the Protista Kingdom including the following:
   • Animal-like: paramecium, amoeba
   • Fungi-like: mildew, molds
   • Plant-like: euglena, diatoms, green algae, red algae, brown algae
2. Ask students to define the major characteristics of this kingdom using these examples.
3. Students should determine that this kingdom is the “left-over” kingdom. Its members are similar to the other kingdoms, but don’t fit all of the characteristics.

Elaborate

(Time: 2 days to plan and gather materials, 30 minutes per day for 5 days to complete experiment, 1 day to organize results)

1. Students will design and complete their own experiment to determine the effect of pH on algae growth. First, you must review the algae growth experiment with the students. Using the counting worksheet, explain how cell counts are completed and even demonstrate it for the class.
2. When students are designing their experiment it is good to give them several good ideas of household chemicals that could be used to make various pH solutions for the experiment. Some groups may use acids and bases and some may focus on a small range in either the acids or bases.
3. Students will use the experimental design graphic organizer to plan their experiment.
4. Ask students to show you their experimental plan, procedure, and materials list before they begin.
5. You may need to adjust the time spent on this part of the lesson depending on your class.

Evaluate

(Time: 1 to 2 class periods)

After students have completed their experiments, organized their data, and graphed their results, students will create a poster to explain their experiment and results. These can be displayed and presented to the class if desired.

The experiment should also be assessed. A rubric is provided below, but should be adjusted according to your requirements.

Assessment

See Evaluate section.

Supplemental information

This is a list of all the attachments used in this lesson.

Critical vocabulary

• eukaryotic
• prokaryotic
• multi-cellular
• unicellular

Cell organelles

• nucleus
• endoplasmic reticulum
• ribosome
• vacuole
• vesicle
• lysosome
• golgi body
• mitochondria
• chloroplast
• cell wall
• cell membrane

Kingdoms

• Animal
• Plant
• Fungi
• Protista
• Bacteria
• Archaebacteria

Comments

This lesson is part of the Critical Thinking in Science Unit. This lesson should be used while teaching Goal 6 of the science curriculum for grade 8 in the North Carolina Standard Course of Study, which focuses on cells. Students are observing a variety of samples using the microscope so it is important to have several slide examples for each kingdom. This lesson focuses on the student’s ability to research and gather observations to create their own study guide of information on organelles, cells, and kingdoms. The ability to use scientific observations and research is important for students. It helps them to organize and apply knowledge.

• Next: Microbiology and infectious disease

Contents: Critical thinking in science

• Next: Microbiology and infectious disease
• Previous: Change over time

(Image source. More about the photograph)

Learn more

• Cell Organelles This section of the CyberSleuth Kids website includes encyclopedia entries on the organelles accompanied by diagrams and images.

Related topics

• Search LEARN NC for more resources on cells and science.

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