Concepts | Questions | Media Resources |
5.1 Membrane Models
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- The present-day fluid-mosaic model proposes that membrane is less rigid and more dynamic than suggested by the previous sandwich model.
| - Describe the fluid-mosaic model of the plasma membrane.
Answer
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Summaries of major points:- Early observations
- In 1972, Singer and Nicolson introduced the currently accepted fluid-mosaic model of membrane structure.
Labeling Exercieses
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5.2 Plasma Membrane Structure and Function
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- The plasma membrane regulates the passage of molecules and ions into and out of the cell.
- The membrane contains lipids and proteins, each with specific functions.
| - What is the difference between peripheral and integral proteins?
Answer - What is the glycocalyx and what are its functions?
Answer - List the five integral proteins found in the plasma membrane.
Answer
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Summaries of major points:- Fluid-mosaic model
- Fluidity of the plasma membrane
- The membrane is a mosaic
Labeling exercise
Lab exercises
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5.3 Permeability of the Plasma Membrane
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- Small, noncharged molecules tend to pass freely across the plasma membrane.
- Some molecules diffuse (move from an area of higher concentration to an area of lower concentration) across a plasma membrane
- Water diffuses across the plasma membrane and this can affect cell size and shape.
- Carrier proteins assist the transport of some ions and molecules across the plasma membranes.
- Vesicle formation takes other substances into the cell, and vesicle fusion with the plasma membrane discharges substances from the cell.
| - What does it mean to be differentially permeable?
Answer - What are the similarities and differences between facilitated and active transport?
Answer - Can a solution always be considered hypotonic? Why or why not?
Answer - What types of molecules are moved into and out of cells via membrane assisted transport?
Answer
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Summaries of major points:- Types of membranes and transport
- Diffusion and osmosis
- Transport by carrier proteins
Animation quizzes
Art Quizzes
Explorations
Study Guides- Movement across membranes
- Endocytosis and Exocytosis
Lab exercises |
5.4 Modification of Cell Surfaces
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- In animals, the activities of cells within a tissue are coordinated in part because of junctions between the cells that allow them to communicate.
- In animals, the extracellular matrix of cells influences their shape, movement, and function.
- In plants, cells have a cell wall which supports the cell. The cell wall has plasmodesmata which permits passage of water and some solutes between cells.
| - What are the functions of adhesion, tight and channel junctions between cells?
Answer - How do collagen and elastin fibers function in the extracellular matrix?
Answer - What are plasmodesmata and what is their function?
Answer
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Summaries of major points:- Plasma membrane
- Plant cell walls
- Extracellular matrix of animal cells
- Junctions between cells
- Cell-cell recognition
Explorations
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