Cell Membrane Flashcards
how permeable is the cell membrane?
semi/selectively permeable
allows some things in and some things out of the cell
how are the heads and tails in the cell membrane? what is this called?
hydrophobic tails
hydrophilic heads
amphipathic
what is the early model of the cell membrane?
sandwich membrane:
protein
hydrophilic zone
hydrophobic zone
hydrophilic zone
what is the current and accurate cell membrane model?
fluid mosaic model
not rigid
hydrophilic region of protein
phospholipid bilayer
hydrophobic region of protein
what components of the cell membrane are in a mosaic pattern?
proteins float randomly in the PLBL
what does the fluid property of the cell membrane allow for?
allows the phospholipid to move easily in a lateral direction
the phospholipids can also sometimes flipflop across the membrane
what gives the cell membrane more fluidity?
the unsaturated/polyunsaturated hydrocarbon tails that have double bonds
what do the saturated hydrocarbon tails do to the cell membrane?
make it more rigid
at room temp, what does adding cholesterol to the cell membrane to it?
lowers fluidity, more rigid
what happens if you add cholesterol to the cell membrane at low temp?
increases fluidity, prevents phospholipids from clumping
what does the versatility of cholesterol at diff temp allow? ex?
allows animals that live in very cold climates to still maintain plasma membrane function
hooves of animals have a lot of cholesterol to prevent freezing when exposed to snow
components of the cell membrane (10)
- ECM/Glycocalyx
- Integral Protein: Transport Protein
- Integral Protein: Integrin Protein
- Integral Protein: Aquaporin
- Cholesterol
- Peripheral Protein
- Cytoplasm and Cytosol
- Phospholipids
- Glycoprotein
- Glycolipid
where are integral proteins located?
span across the phospholipid bilayer
structure of integral proteins
alpha helixes (secondary structure)
what do transport proteins do?
allow specific molecules to enter or exit the cell
what do integrins do?
used for cell communication
where are peripheral proteins found?
usually found on the inside ofthe cell membrane
peripheral protein function
give strength to cell
what bring the selectively permeable nature to the membrane?
hydrophobic/nonpolar tails
what molecules would not be able to get pass the nonpolar tails?
ionic/charged molecules, most polar molecules, large molecules
what molecules would easily get past the nonpolar tails?
nonpolar, small, gases, steroids
what will the molecules that cannot get past the cell membrane use?
use specific transport proteins that have a charged interior
what does water use to enter and exit the cell membrane?
transport protein called aquaporin
what is diffusion?
tendency for molecules to spread out in an open space
diffuse from a high to low concentration
spontaneous and require no ATP
passive transport
what is osmosis?
passive transport of water from high to low concentration across a semi permeable membrane