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Critical Thinking in Science

Part 6: Cells

Introduction:

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.

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.

Curriculum Alignment:


1.01 Identify and create questions and hypotheses that can be answered through scientific investigations.

1.02 Develop appropriate experimental procedures for:

  • Given questions.
  • Student generated questions.

1.04 Analyze variables in scientific investigations:

  • Identify dependent and independent.
  • Use of a control.
  • Manipulate.
  • Describe relationships between.
  • Define operationally.

1.05 Analyze evidence to:

  • Explain observations.
  • Make inferences and predictions.
  • Develop the relationship between evidence and explanation.

1.06 Use mathematics to gather, organize, and present quantitative data resulting from scientific investigations:

  • Measurement.
  • Analysis of data.
  • Graphing.
  • Prediction models.

1.08 Use oral and written language to:

  • Communicate findings.
  • Defend conclusions of scientific investigations.
  • Describe strengths and weaknesses of claims, arguments, and/or data

6.02 Analyze structures, functions, and processes within animal cells for:

  • Capture and release of energy.
  • Feedback information.
  • Dispose of wastes.
  • Reproduction.
  • Movement.
  • Specialized needs.

6.04 Conclude that animal cells carry on complex chemical processes to balance the needs of the organism.

  • Cells grow and divide to produce more cells.
  • Cells take in nutrients to make the energy for the work cells do.
  • Cells take in materials that a cell or an organism needs.

Classroom Time Required:

Approximately 280 minutes, divided as describes below. Students can also complete some of the research on their own to decrease the required time.

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
  • Copies of Organelle chart, Organelle Function Checklist, Cell chart, and Kingdom Chart

Research materials:

  • internet, books, encyclopedias, articles, text book, etc.
  • Grids for cell counting- print small grids on overheads 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:

Computer, Projector, student computers with internet access if possible

Pre-Activities/ Activities:

Pre-Activity:

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

Engage:

  • What are cells? (Time: 20 minutes)
  • Assess prior knowledge: Ask the students to describe cells, give examples of cells, and draw a picture of a cell.
  • Students should then pair up with their neighbors and compare their answers to the above questions.
  • As a class, share student ideas on cells.

Explore:

  • Cells have Organelles (Time: 50 minutes)
  • The students will begin by looking at the cell organelles.
  • Find Electron Microscope images of the following organelles: Nucleus, Mitochondria, Chloroplast, Golgi Body/Apparatus, Cell Wall, Cell Membrane, Lysosome, Endoplasmic Reticulum, Ribosome, Vacuole, Vesicle, Cytoplasm
  • Print these images for each student. Make sure they are small enough to fit in the square on the paper.
  • Give each student 6 copies of the Organelle Chart Worksheet (See Worksheet 1). (Or 3 pages front to back) Each student should also receive a small, printed electron microscope image for each organelle.
  • Discuss what an electron microscope is and why it is important to use this tool when studying the structure of an organelle.
  • Students should complete each organelle chart by:
  • Writing the name of the organelle at the top of the paper
  • Describe the function of the organelle in the provided space
  • Paste the organelle image in the electron microscope image square
  • Create a drawing of the organelle- this should look like the “cartoon” images students often see
  • In order for students to accurately complete the organelle pages you can either:
  • Create a Power point of the cell organelle functions, electron microscope images, and “cartoon” drawing 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)
  • Students will complete the Organelle job checklist to more clearly define the role of these organelles in the cell (See Worksheet 2).
  • Organelles in Cells (Time: 2-50 minutes class periods)
  • The students will use the microscope to view various cell samples and identify the visible organelles.
  • Each sample will be drawn under low power (for cell to cell structure) and high power (cell detail/organelles) (See Worksheet 3).
  • Students should color their drawings and label the important details.
  • Students will identify the organelles that were visible.
  • You will need to help the students identify the organelles that were present but NOT visible with the microscope.
  • Students should be provided with 2 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)
  • Students will use their cell worksheets to characterize the Animal, Plant, Fungi, and Bacteria kingdoms.
  • Students will complete the Kingdom Chart for these four kingdoms (See Worksheet 4).
  • Option 2: Why are Archaebacteria in a separate kingdom? (Time: 20 minutes)
  • Ask students to research the defining characteristics of this kingdom and determine why it is its own kingdom.
  • Option 3: What is the Protista kingdom? (Time: 40 minutes)
  • Give students several examples of members of the Protista kingdom:
  • Animal-like: Paramecium, amoeba
  • Fungi-like: mildew, molds
  • Plant-like: Euglena, diatoms, Green Algae, Red Algae, Brown Algae
  • Ask students to define the major characteristics of this kingdom using these examples.
  • 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/day for 5 days to complete experiment, 1 day to organize results)
  • 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 Directions (See Worksheet 5) with the students. Explain how cell counts are completed and even demonstrate it for the class (See Worksheet 6).
  • 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.
  • Students will use the experimental design graphic organizer (See Worksheet 7) to plan their experiment.
  • Ask students to show you their experimental plan, procedure, and materials list before they begin.
  • You may need to adjust time for this depending on the 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 display to explain their experiment and results. These can be displayed and presented to the class if desired. A rubric is provided, but should be adjusted according to your requirements.

Assessment:

See evaluation section.

Modifications:

  • EDGO can be edited for any motor skill deficiencies by making it larger, or making it available to be typed on.
  • All basic modifications can be used for these activities.
  • The experiment can be adjusted as necessary.

Critical Vocabulary:

  • Eukaryotic
  • Prokaryotic
  • Multi-cellular
  • Unicellular
  • Cell Organelles (nucleus, endoplasmic reticulum, ribosome, vacuole, vesicle, lysosome, golgi body, mitochondria, chloroplast, cell wall, and cell membrane)
  • Kingdoms (Animal, Plant, Fungi, Protista, Bacteria, and Archaebacteria)

Comments:

This lesson is part of the Critical Thinking in Science Unit. This lesson should be used while teaching Goal 6 of the North Carolina Standards of Learning (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. Students also have a chance to experiment with the needs of living things. The students will gain considerable knowledge by planning, performing, analyzing, and presenting their experiment.