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AP® Biology · Unit 2 · Topic 2.3

Plasma Membrane: Topic Checklist (Biology 2.3)

Specific “I can…” statements for the plasma membrane and the fluid mosaic model, each linked to the guide section and practice question that shows whether you can really do it.

Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.

Understanding

  • I can explain why phospholipids form a bilayer with polar heads facing the fluid on both sides and nonpolar tails facing each other. (Guide: “Phospholipids: heads out, tails in”; Practice Q1)
  • I can explain why the bilayer forms and stays together without the cell spending energy. (Guide: “Phospholipids: heads out, tails in”; Practice Q7)
  • I can predict which regions of a membrane protein are hydrophobic and which are hydrophilic from where they sit, including the lining of a pore. (Guide: “Membrane proteins”; Practice Q2)
  • I can tell integral proteins from peripheral proteins and explain how each is held in the membrane. (Guide: “Membrane proteins”; Practice Q5)
  • I can name the components of the fluid mosaic model and describe the role of each in keeping the internal environment of the cell steady. (Guide: “What each component does for the cell”; Practice Q4)
  • I can explain what “fluid” and “mosaic” each mean in the fluid mosaic model. (Guide: “The fluid mosaic model”; Practice Q7)

Calculation and skills

  • I can label a membrane diagram, decide which side is the outside of the cell and justify it. (Guide: “Reading membrane diagrams”; Practice Q4)
  • I can calculate the length of an α-helix from its number of amino acids and judge whether it can span the membrane. (Guide: Worked example 1; Practice Q3)
  • I can calculate the percentage of fluorescence recovered after photobleaching, and a mean and percentage change from repeats. (Guide: Worked example 2; Practice Q6)

Reasoning

  • I can use photobleaching data to argue that membrane proteins move sideways, and explain why some recover less. (Guide: Worked example 2)
  • I can explain the purpose of a control in a membrane experiment and propose a better one. (Guide: Worked example 2; Practice Q6)
  • I can describe what a membrane diagram or model leaves out, and correct errors in a student’s model. (Guide: “Reading membrane diagrams”; Practice Q4, Q7)

All ticked? Move on to Topic 2.4, Membrane Permeability, or return to the course roadmap.

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