Using students' prior knowledge from the lesson on cell organelles, students will respond to the following prompt:
Students are also encouraged to draw a basic diagram of the animal cell and the egg to create a visual side-by-side comparison to support their stance.
By making the opening prompt of this lesson a statement that must be evaluated by the students, students are able to activate their prior understanding and incorporate their writing skills to develop a claim and provide evidence to support their stance. This open-ended brief writing assignment engages student creativity in a more rigorous manner, rather than a simple yes or no question.
Sample of Student Work: Egg Analogy - Students seemed to relate to this analogy and were able to build their understanding on this very simple comparison.
Due to the detailed structure and complex functions that occur to enable movement across the cell membrane, the teacher will dedicate a majority of this lesson to introduce and reinforce the details of cell membrane structure, as well as the processes of osmosis and diffusion. TheseLecture Notes - Cell Membranewill introduce students to the features of the cell membrane and incorporate the organic molecules that were studies in prior lessons, such as the individual lessons that each focused on proteins, carbohydrates and lipids.
It is essential for students to have a strong comprehension of the cell membrane composition to truly understand cellular function as the class progresses in their cell biology curriculum!
This lesson consists mostly of teacher-led direct instruction. If you feel that your students do not need the intense content delivery for an extended time, you may want to compress the lecture notes and combine with the next lesson: In&Out to best meet the academic needs of your student population.
Common Student Misconceptions and How To Avoid the Pitfalls:
Students will watch the video below to reinforce the Lecture Notes - Cell Membrane that describe the movement into and out of the cell. This video provides a visual model of the interaction of cells in hypertonic, hypotonic, and isotonic solutions. Students are encouraged to take notes during the video so they have evidence from the Naked Egg Lab to develop a narration that explains the interaction of cells in each of the these three types of environments.
At the conclusion of the video, students will use their video notes and Lecture Notes - Cell Membrane to develop a narration that describes the movement of molecules when a cell (or naked egg) is placed in a hypertonic, hypotonic, or isotonic solution. Students will need to draw a model of the movement of molecules across the cell membrane to depict molecules moving into, out of, or both into and out of the cell.
Once complete students will share their narrations in their lab groups of 3-4 students to ensure the details of each student's narration is accurate and reflects the information provided in the lecture notes.
Sample of Student Response #1: Using the egg as an analogy for a cell simplified the process and supported all students to understand the process of moving material into and out of the cell.
Sample of Student Response #2: This sample provided great details and demonstrates a strong understanding of the concept.
As a close to the lesson, students will create their own definitions that differentiate the process of osmosis and diffusion. Students are encouraged to use their own wording and not just copy their lecture notes or textbook. Students will also provide evidence from the gummy bear or egg examples that were provided during the lesson.
Once students have finalized their definitions with examples for both terms, they will turn to their neighbor to share their newly drafted definitions. Students will collaborate to determine if the definitions and examples are accurate and appropriate for this activity.
Sample of Student Response - This student used their experiences in the lesson to develop an original definition of the terms osmosis and diffusion.
Students will complete Reinforcing Activity: Movement Across the Membrane as homework to practice the concepts that were introduced in today's lesson.