Muscle Cells (breaking the mold) and diffusion

Concept or conceptual understanding: This activity will introduce the concept of diffusion.  Students will find out through examination of a muscle cell that in science modeling is a commonly used tool, but often models do not describe the diversity seen in real life.  Students will examine the importance of diffusion to cellular function. 

Real world connections (Relevancy):  Diffusion is a fundamental and foundational concept in life processes.  Understanding concentration gradients is a necessity for understanding all chemical and electrical processes. 

AZ standards: Science Standards Articulated by Grade Level- High School

S4C1PO3.  Explain the importance of water to cells.

S4C1PO4.  Analyze mechanisms of transport of materials (e.g., water, ions, macromolecules) into and out of cells:

·         passive transport

·         active transport

S5C1PO5.   Describe the properties of electric charge and the conservation of electric charge.

Incorporation of inquiry: Through analysis of the structure of a muscle cell students will consider the accuracy of previously introduced cell “models.”  Students will discuss the pros and cons of using a generic model in science.  Students will examine and discuss the importance of diffusion in cells 

Behavior objectives:

Examine the structure of a muscle cell.

Compare the muscle cell to previously identified cell models and discuss differences and similarities.

Consider the purpose of models in science and discuss.

Consider the previously introduced structure of muscle and discuss the importance of diffusion to cell function and organism function via movement.

Prior knowledge necessary:

Students will participate in class discussion about diffusion.  Previous lectures will describe the cell and muscle function.

Identify possible student preconceptions:

Diffusion is just a concept, but isn’t really important to life.  All cells look like the fried egg model of a cell.  (Or all plant cells look like a green box.)

Materials:

Slides and models of various cells.

Online diffusion exercise

Safety:

At this time there are no safety concerns for this lab

Lesson Description:

Begin the lesson by introducing diffusion in a lecture.

Ask the students to draw a cell.

Introduce a muscle cell.

Compare the muscle cell with the students’ cell drawings.

Discuss the idea of a model in science.  Look at pros and cons of usage.

Return the discussion to muscle cells and diffusion.

Re-enact the students working muscle activity with calcium infusion driving (turns on!) movement.

Finish lecture with super cool examples of diffusion gone wrong....puffer fish poison (tetrodotoxin), gila monster bite (other neurotoxin) and nicotine. 

Assessment:

The assessments are mostly formative for this lesson – Students will be observed as they draw a cell.  Participation in discussion is highly important.  There will also be a guided note sheet for the lecture on diffusion.