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Exploring Structure and Function in Biological Systems

In this media-rich lesson, students analyze structure and function relationships at different levels of organization in nonbiological systems and then perform a similar analysis using biological systems.

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Lesson Summary

Overview

In this lesson plan, students explore structure and function relationships at different levels of organization in biological systems. Students begin by considering levels of organization in their communities, houses, and rooms. They examine necessary functions that occur at each level and compare and contrast them. They next perform a similar analysis using biological systems: the cow eye, the single cell, and the molecules associated with protein synthesis. Finally, students use what they have learned to analyze structure and function relationships that are associated with the disease sickle cell anemia.

Objectives

  • Distinguish between levels of organization in biological systems
  • Understand how levels of organization are connected across systems
  • Describe structure and function relationships in:
    • the cow's eye
    • the single cell
    • molecules associated with protein synthesis
  • Explain how the mutation associated with sickle cell anemia leads to a structural change in a protein that causes the circulatory system to function abnormally

Grade Level: 9-12

Suggested Time

  • Four to five 45-minute class periods

Multimedia Resources

Materials

Before the Lesson

  • If possible, arrange computer access so that all students can work individually or in pairs.
  • Print hard copies of the Eye Diagram PDF Document.
  • Prepare overhead transparencies and copies of all remaining handouts listed under Materials.

The Lesson

Part I: Levels of Organization

1. Ask students, "What do you think is meant by the phrase, levels of organization?" After soliciting students' responses, guide the discussion to focus on human levels of organization. Examples that may come up include the following:

  • local, state, and federal government
  • immediate family and extended family
  • school and school district
  • high school sports, college sports, and professional sports

2. Explain that although there are some differences as you go from one level of organization to the next, there are important similarities as well. Display a map of your local community to the class. Ask students, "What are some basic needs of our community that must be met in order for people to be healthy and productive?" Guide a discussion that brings out the following:

  • The community requires food and water.
  • The community must remove waste products.
  • The community requires shelter for its members.
  • The community requires a transportation system.

3. Ask students, "Does your household have any of these same needs?" Students will recognize that their household has most, if not all, of these same needs. Give each student a copy of the Levels of Organization: Communities to Rooms PDF Document. Instruct students to describe in the spaces provided how their community and their household meet each of the needs listed. For now, the "Room" column should be left blank.

4. Display an overhead transparency of the handout. Ask for volunteers to read their responses to the class. Summarize their answers on the transparency. Guide the discussion to bring out the following:

  • Both communities and households require food and water, typically from outside sources.
  • Both communities and households must remove waste products.
  • Both communities and households must provide shelter for their inhabitants.
  • Both communities and households must have transportation systems. (Note: Transportation with regard to a household should focus on the stairs and/or hallways that people use to get around the house, not on cars that they use to travel through their community.)

5. Ask students, "Does each room in your house or apartment meet each of these needs?" Instruct students to fill in the column labeled "Room" on their handouts.

6. After students have finished filling in the last column, ask for volunteers to read their responses aloud. Guide the discussion to stress that rooms are designed to have specific functions such as kitchens, bathrooms, and family rooms.

Part II: Exploring an Organ System

7. Explain to students that they will explore examples of structure and function relationships at the organismal, cellular, and molecular levels. Pass out a copy of the Eye Diagram PDF Document and Parts of the Eye: Structure and Function PDF Document to each student. Explain to students that they will watch a video showing the dissection of a cow's eye. Instruct students to:

  1. select three of the labeled structures on the Eye Diagram PDF Document;
  2. view the Cow's Eye Dissection Flash Interactive;
  3. describe the function of each of the three eye parts they have selected (using the middle column on their handouts); and
  4. describe how the structure of each part relates to the function it carries out (using the last column).

Note: To ensure that all parts of the eye are analyzed, you may wish to assign them to students.

8. After students have completed their tasks, ask for volunteers to describe their structure and function relationships.

Part III: Exploring a Cell

9. Tell students that they will now explore the parts of a cell and, as with the cow eye, relate structures to functions. Pass out a copy of the Parts of a Cell: Structure and Function PDF Document to each student. Explain that they will watch a video about the structures found in a eukaryotic cell. Instruct students to:

  • select three of the cell organelles;
  • view the Organelles in the Cytoplasm QuickTime Video;
  • describe the function of each of the three organelles they have selected (in the middle column on their handouts); and
  • describe how the structure of each of the three organelle relates to the function it carries out (in the last column).

Note: To ensure that all organelles are analyzed, you may wish to assign them to students.

10. After students have completed their tasks, ask for volunteers to describe their structure and function relationships.

11. Break students up into small groups. Give each group a copy of the Levels of Organization: Organisms to Organelles PDF Document. Explain that this time they will explore levels of organization in an organism. As before, instruct students to describe on their handouts how each level of organization meets their needs. Before proceeding, make sure that students understand the definition of an organelle.

12. After students have finished filling out their handouts, initiate a discussion that brings out the following:

  • Both the organism and the cell must bring in food and waste from the outside.
  • Both the organism and the cell must remove waste products.
  • Both the organism and the cell must be protected from their environments.
  • Both the organism and the cell must have transportation systems.
  • The organelles in the cell are specialized as to their functions in a similar way that the rooms in a house serve specific functions. Ask students to provide examples of organelles and their specific functions.

Part IV: Exploring Molecules

13. Tell students that they will explore the molecules associated with protein synthesis and relate the structures of the molecules to their functions. Pass out a copy of the The Molecules of Protein Synthesis PDF Document to each student. Explain to students that they will watch an animation about protein synthesis. Instruct students to:

  1. view the How Do Cells Make Proteins? Flash Interactive;
  2. describe the functions of each of the four types of molecules listed on their handouts (in the middle column); and
  3. describe how the structure of each of the four types of molecules relates to its function in protein synthesis (in the last column).

Note: Students will find it challenging to relate the structures of these molecules to their functions. In the discussion that follows, try to bring out the following:

  • DNA: the base pairs must be aligned properly so that A and T form hydrogen bonds, and C and G form hydrogen bonds. The structure (sequence) of one strand determines the structure (sequence) of the other strand.
  • RNA polymerase: the protein must be able to attach to and move along a DNA strand in order to read it. This also means that the protein must be able to distinguish the shapes of the different bases.
  • mRNA: the molecule must have dimensions that allow it to pass through pores in the nuclear membrane.
  • Ribosome: the ribosome contains proteins and RNA. The basic shape of the ribosome must permit it to attach and move along the mRNA. Ribosomal RNA is used to recognize and position the mRNA within the complex.

14. After students have completed their tasks, ask for volunteers to describe their structure and function relationships.

15. To conclude this activity, conduct a class discussion that addresses the advantages of applying a "levels of organization" approach to these systems. Discuss the following questions:

  1. What similarities exist across levels?
  2. What differences exist across levels?
  3. Think back to the opening analogy of the local community. In what ways was the community a good model? In what ways was the community a poor model?

Part V: Applying Knowledge

16. Explain to students that they will apply a structure and function analysis to help them understand the disease sickle cell anemia. Show students the A Mutation Story QuickTime Video. After showing the video, instruct students to address in their notebooks:

  1. the functions of:
    • hemoglobin
    • a red blood cell
    • a capillary
    • the circulatory system
  2. For each of the above terms, provide a description of how structural elements enable function.
  3. Describe how the mutation associated with sickle cell anemia causes a structural change in the hemoglobin molecule.
  4. Describe how the sickle cell form of hemoglobin affects the structure and function of red blood cells and the function of the circulatory system.

Check for Understanding

Ask students to reflect on the videos and interactive activities used during this lesson. Have them address the following in their notebooks:

  1. Select a function important to survival, such as those listed on the Levels of Organization handouts. Describe how an organelle serves that function.
  2. Select a different function important to survival from those listed on the Levels of Organization handouts. Identify two types of cells that serve that function and describe how they meet the need.
  3. Select a different function important to survival from those listed on the Levels of Organization handouts. Identify two body structures that serve that function.

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