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FINAL Chapter 7: Membrane Structure and Function

Terms in this set (20)

What does "selectively permeable" mean?
allowing some substances to cross it more easily than others
Describe the fluid mosaic model
*include the arrangement of the phospholipid bilayer of the plasma membrane and the location and function of the proteins, carbs, and cholesterol
The membrane is a amphipathic phospholipid bilayer (have a hydrophobic and hydrophillic region) with a "mosaic" of various proteins embedded in it. Proteins are embedded into the membrane, either peripheral or integral. Carbs are found on the exterior and are either attached to lipids or proteins. Cholesterol enhances fluidity at lower temps
What are the hydrophilic portions of the cell membrane?
phosphate heads
What are the hydrophobic portions of the cell membrane?
phosphate tails
Channel proteins
hydrophilic channel that certain molecules/ions can use as a tunnel, involved in facilitated diffusion
Carrier proteins
bind to molecules and change shape to shuttle them across the membrane
Aquaporins
special channel proteins for the passage of water
Integral proteins
often penetrate and extend through the membrane, with 2 hydrophilic regions
Peripheral proteins
attached to the surface of the membrane
Passive diffusion
higher conc. to lower conc.
Osmosis
for water
Facilitated diffusion
higher conc. to lower conc., need a transport protein
Active transport
lower conc. to high conc. (against conc. gradient), need a carrier protein, requires ATP
What does passive transport play a primary role in?
the import of resources and the export of waste
Isotonic solution
*for next 3 include examples and how the cell responds to each environment
water flows across the membrane at same rate in both directions
ex. same salt conc. in and outside the cell
Hypertonic solution
cell will lose water to its surroundings and will shrivel/die
ex. when you drink salt water
Hypotonic solutions
water will enter the cell faster than it leaves and it will swell/ burst
ex. lady who drank water for a wii
Exocytosis
vesicles from the cell's interior fuse with the cell membrane, expelling their contents
Endocytosis
the cell takes in macromolecules by forming vesicles from the plasma membrane
What is the difference between phagocytosis and pinocytosis?
phago: "cellular eating"
pino: "cellular drinking" like pino wine
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