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WorksheetsMembranes I
Total questions: 16
Worksheet time: 11mins
Fill in the blank. Membranes provide the _____ of the cell.
ceiling
floor
energy
walls
Membranes differ in their lipid composition, but protein compositions are the same.
True
False
Lipids constituting the basic bilayer structure of the plasma membrane
are bound to each other by noncovalent forces and can move laterally within the membrane
are restricted in their lateral movement within the membrane
are loosely bound to the membrane and can readily be removed
account for more than 70% of the mass of most animal cell membranes
All of the lipid molecules in cell membranes are amphipathic (or amphiphilic). They have a hydrophilic polar end and a hydrophobic nonpolar end.
True
False
The most abundant membrane lipids are the
phospholipids
cholesterol
glycolipids
sphingolipids
The lipid bilayer is semipermeable membrane. Small, non-polar molecules such as these are able to traverse the membrane freely.
oxygen and carbon dioxide
sodium and carbon dioxide
oxygen and chloride ions
sodium and chloride ions
Individual phospholipids will spontaneously flip flop between leaflets with regularity.
True
False
Cholesterol and the rigid sterol rings serve to
stiffen and strengthen the adjacent portion of the hydrophobic core
loosen and add to the fluidity of the plasma membrane
allow the transport of molecules across the membrane
cause many problems and have no benefit
The phosphatidylcholine molecules of any particular membrane are
a mixture of different molecular species, with fatty acids of different chain length and number of double bonds
a single molecular species, with fatty acids of the same chain length and double bonds
not respectful to their fatty acid composition
filled with double bonds in the constituent fatty acids which decrease the fluidity of the membrane
Proteins embedded in the plasma membrane have a variety of different functions. The four functional classes of proteins are
transporters, anchors, receptors, and enzymes
transporters, rejectors, receptors, and enzymes
inspectors, transporters, receptors, and enzymes
anchors, enzymes, rejectors, enzymes
When visualized in cartoon form, each phospholipid molecule is drawn as a
circle or oval and two long tails
circles tightly lined up next to eachother
circular nonpolar head and polar hydrocarbon chains
none of the above
A mixture of phospholipid molecules makes up a
membrane
2 chainz
cartoon
complex lipid
All the phospholipids making up a specific membrane
must be the same
are a mixture of different molecules
have a polar head group and two tailed structure
are a mixture of different molecules which all have a polar head group and two tailed structure
The outer leaflet contains _____ phosphatidylcholine and sphingomyelin. It also contains the _____.
more, glycolipids
less, glycolipids
more, phosphatidylethanolamine
less, phosphatidylethanolamine
The inner leaflet contains _____ phosphatidylserine and _____.
more, glycolipids
less, glycolipids
more, phosphatidylethanolamine
less, phosphatidylethanolamine
The phospholipids phosphatidylcholine and sphingomyelin have the ____ polar head group derived from _____
large, choline
small, choline
same size, choline
large, myeline
