1.4 Cell Membranes and Diffusion Principles Flashcards
What is the fluid mosaic model?
membrane is a phospholipid bi layer in which proteins are partially or entirely embedded and they can move freely in the membrane
What are the two primary components of the cell membrane?
lipids
proteins
What are amphipathic phospholipds? How do they align in the cell membrane?
have hydrophilic and hydrophobic ends
align into bilayer with hydrophilic heads facing out and hydrophobic tails facing each other
What does hydrophilic mean?
water loving
What does hydrophobic mean?
water hating
What allows the lipids and proteins to move laterally in the cell membrane?
hydrophobic tails
What is the function of cholesterol in the cell membrane?
stabilizer against heat and cold; acts as a space between tails to reduce solidification
Is cholesterol hydrophobic or phillic?
hydrophobic
What are integral proteins?
proteins that span across the lipid bilayer
What are peripheral proteins?
proteins the are located only on the inner or outer surfaces of the cell membrane
What is responsible for the selective permeability of the cell membrane?
arrangement of lipids and proteins
In general, what are cell membranes most permeable to?
small molecules
lipid soluble substances
What can easily pass through the cell membrane and why?
Water molecules since they are small
What are the three methods by which particles can cross the cell membrane?
diffusion
active transport
special methods
What is diffusion?
small molecules move from an area of higher to lower concentration across cell membrane
