Cell Membrane Flashcards
(46 cards)
the cell membrane model that says the plasma membrane is neither rigid nor static in structure but is highly flexible and can change its shape and composition through time.
fluid mosaic model
made of two layers of
lipids that have hydrophilic
heads and hydrophobic tails.
- Most abundant lipids in membranes
- widely accepted
phospholipid
if phospholipids have hydrophilic heads and hydrophobic tails, what is it called?
amphiphatic
how many heads and tails does a phospholipid have
1 head, 2 tails
The ______ of a phospholipid is made of an alcohol and phosphate (PO4) group, while the ______ are chains of fatty acids. (hydrocarbon, CH3, CH2)
head, tails
This head is connected to a _________ with two hydrophobic tails called fatty acids.
glycerol
The cell membrane consists of a diversity of ________, __________, and __________
lipids, carbohydrates, proteins
fatty acids that have single bonds (palmitic acid)
saturated fatty acids
(true or false) The individual lipid molecules
are able to move in their own monolayer.
true
fatty acids that have double bonds (linoleic acid)
unsaturated fatty acids
movement of individual lipids in the cell membrane
- lateral - going from one place to another laterally (most abundant)
- rotation - the movement of lipid on its own axis
- flip flop - moving from one side to the side (not lateral, rarely occurs)
- flexion - more like a result of a movement, so that a lipid can move freely
other than cholesterol, what helps in maintaining the membrane’s fluidity
the presence of double bonds
it is an essential component of animal cell plasma membranes. it modulates the bilayer structure of biological membranes in multiple ways. It changes the fluidity, thickness, compressibility, water penetration, and intrinsic curvature of lipid bilayers.
cholesterol
at warm temperature, the membrane ________, hence the cholesterol _________
expands, restrains movement
at cool temperature, the membrane ________, hence the cholesterol ______________
compresses, maintains its fluidity by preventing tight packing
“good” cholesterol, absorbs cholesterol and carries it back to the liver. The liver then flushes it from the body. High levels of this cholesterol can lower your risk for heart disease and stroke.
high-density lipoprotein
cholesterol is only present in _______
animals
sometimes called “bad” cholesterol, makes up most of your body’s cholesterol. High levels of this cholesterol raise your risk for heart disease and stroke.
low-density lipoprotein
synthesized by plants only, helps maintain its temperature, helps in lowering LDL in the blood
phytosterol
believed to have very similar functions to those of sterols in the membranes of animals and plants in that they can intercalate into phospholipid bilayers and modulate the fluidity of membranes by interacting with their complex lipid components. (in bacteria)
hopanoid
a function of the membrane that means it can:
- keep desirable substances in the cell and also keep undesirable substances out. (acid in the stomach)
- Hydrophobic core prevents the transport of ions and polar molecules (it selects what goes in and out)
- define the boundaries
- act as permeability barriers
can a small and non-polar molecule pass through the cell membrane? (O2, CO2, steroid hormones, N2)
yes
can a small polar molecule pass through the cell membrane? (H2O, ethanol, glycero;)
yes but slow
can a large non-polar molecule pass through the cell membrane? (Carbon Rings)
yes but slow
