BIO 181 Lecture 4.1

Lecture 4.1: Membranes and Membrane Transport


An essential step in the evolution of life was the compartmentalization and confinement of biochemical reactants so that metabolic reaction sequences could occur efficiently. Membranes provide the solution to the problem. Very simple in structure, membranes are made of soap. Therefore, they are actual soap bubbles. But don’t get the idea that this makes them fragile. They are extremely stable in water, and will not allow water or water-soluble materials to pass through them. However, cells need water-soluble materials; therefore, living membranes contain a variety of embedded proteins–integral membrane proteins–that control what goes into and out of the cell.


  1. Review Sections 6.1 of the textbook.
  2. Read Sections 6.2 through 6.4 of the textbook.
  3. Download Lecture 4.1 slides.
  4. Do one of the following:
    1. In-person section: Attend Lecture 4.1.
    2. Online section: Watch the following videos:
      1. Video 4.1.1, Membrane Structure.
      2. Video 4.1.2, Membrane Transport.
  5. Complete the questions on Study Guide 4.1.


After completing the activities, log into Canvas, launch BIO 181 and complete Lec 4.1 Quiz.

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