Conduct an investigation to demonstrate how the cell membrane maintains homeostasis through the

 Expanded Standard header image

Disciplinary Core Idea

LS1: From Molecules to Organisms: Structures and Processes

Students are learning about the functions of different parts in cells. The students model a cell part with a screen that sorts large objects from small objects. When objects of different sizes are placed on the screen, the screen allows the smaller objects to pass through it but not the larger objects.

Students are learning about the functions of different parts

Which of these cell functions is most likely being modeled?

Standard Text and Component Idea

Explanation and Support of Standard

Crosscutting Concept

Science and Engineering Practice

7.LS1.2 Conduct an investigation to demonstrate how the cell membrane maintains homeostasis through the process of passive transport.

Component Idea:

A. Structure and Function

The most critical functions of the cell membrane are maintaining cell structure and controlling the materials entering the cell.

A typical and sufficient phenomenon for this standard includes dissolving the egg shell from an egg and exposing the egg to varying solutions. It is not necessary for students to memorize terms describing the solutions (e.g. hypertonic), however students should work with models representing the microscopic components of the solution to make sense the macroscopic changes to their eggs. It is critical that students draw their understanding of this concept beyond simply explaining this one instance of passive transport, but also other analogous instances. Examples might include explaining the function of the contractile vacuoles in plants, or the way that some plants such as Mimosa pudica utilize solute concentrations to “reset” after they have been touched.

Systems and System Models

Students develop models to investigate scales that are beyond normal experiences.

Planning and carrying out controlled investigations

  Students begin to investigate independently, select appropriate independent variables to explore a dependent variable and recognize the value of failure and revision in the experimental process.