CK-12 Foundation
Ck 12: Life Science: Passive Transport
[Free Registration/Login may be required to access all resource tools.] The cell membrane is semi-permeable. Sometimes molecules need the help of special transport proteins or an input of energy to help them move across it. When an input...
PBS
Pbs Learning Media: Interactive Lessons Collection
Interactive lessons on a range of subjects and grade levels. Each presents content from a public media production, specially tailored to the curricular needs of the classroom. All of these lessons can be used to teach English Language...