Chapter 6: Lipids, Membranes, and the First Cells Flashcards
Hydrocarbons
Hydrophobic non-polar molecules that are composed of entirely hydrogens and carbons in different combinations
Fatty Acid
Non-polar hydrocarbon tail with a head composed of carboxylic acid
“Fatty” part is the hydrocarbon chain
Saturated Fat
Fatty acid completely saturated with hydrogens, with only single bonds between hydrogens and carbons
Unsaturated Fat
Hydrocarbon chains with one or more double bonds, which form a “kink” in the chain
Ester Linkage
Linkage between glycerol and fatty acid molecules
Amphipathic
A substance with both hydrophilic (polar) and hydrophobic (non-polar) regions
Lipid Bilayer
Created when lipid molecules align in paired sheets (think 2 ply paper, with the tails of each lipid pointing to eachother)
Micelles
Singularly layered phospholipids that organize into spherical aggregates
Selective Permeability
A quality of the cellular membrane where certain substances can pass through the membrane more easily than others
Diffusion
When molecules tend to move from high concentrations to lower concentrations
Concentration Gradient
Difference in concentration from one area compared to another
Equilibrium
Where both sides of a concentration gradient have reached equal concentration levels
Passive transport
Doesn’t require energy input to happen. Spontaneous process when happening.
Passive Transport Proteins
Points in the cell membrane where particles can move through the membrane if the concentration gradient favors it.
Osmosis
Only occurs when solutions are separated by a membrane that is permeable only by water and not other solvents.
Hypertonic
Hypotonic
Isotonic
At equilibrium
Fluid Mosaic Model
Transmembrane Proteins
Span the entirety of a membrane, serve as a “tunnel” protein through the membrane. AKA Integrins from Exam 2.
Transmembrane proteins depicted in red.
Peripheral Membrane Proteins
Proteins attached to the plasma membrane that do not go completely through the membrane. AKA peripheral proteins from Exam 2.
Electrochemical Gradient
Electrochemical difference across a cell membrane. Most animal cells have a 50 millivolt difference across the cell membrane.
Facilitated Diffusion
Passive diffusion facilitated by assisting proteins which allow substances to cross the plasma membrane that otherwise would not be able to. Requires no energy.
Active Transport
Transport through the cell membrane that requires energy input to happen. Usually moves against the concentration and electrochemical gradients
Secondary Active Transport
Pump proteins pump ions to another area to create an electrochemical gradient, which will force the diffusion of another substance through the plasma membrane. Secondary transporter doesn’t require ATP to operate.
Saturated lipid structure
Single bonds, so stack on top of eachother in a straight line, normally in solid state
Unsaturated lipid structure
Have kinks, double bonds change the angle of the hydrocarbon chain so they don’t stack in a single straight line, normally in liquid state
Wax lipid structure
Very long hydrocarbon chains, wax doesn’t have a carboxylic head, therefore wax molecules are very strong and can conform to well organized shapes. Usually in solid state
How does hydrogenation affect the structure and physical state of unsaturated oils
Adding hydrogens to the carbon atoms which have double bonds with hydrogen removes the double bonds, so it converts the oil to a saturated fat.
Define 4 parts of a phospholipid
Fatty acids + glycerol + phosphate + an R group
What makes cholesterol and phospholipids amphipathic
Both molecules have one portion that is polar and one that is non-polar. Cholesterol has a polar alcohol group at one end while it has a nonpolar isoprenoid tail at the other end that makes it amphipathic. Phospholipids have a polar head with a nonpolar tail that makes them amphipathic.
