Cell Membrane Composition and Function Quiz

Cell Membrane Structure and Composition

• The lipid bilayer is about 5 nm thick and forms the basic fluid structure of the cell membrane, serving as a barrier to most water-soluble molecules.
• Most membrane proteins span the lipid bilayer and mediate various functions, including molecule transport, catalysis, and structural connections.
• Approximately 30% of proteins encoded in an animal's genome are membrane proteins, essential for cell function and interaction with the environment.
• Lipid molecules, mainly phosphoglycerides, sphingolipids, and sterols, constitute about 50% of the mass of most animal cell membranes, with the rest being protein.
• Phospholipids, the most abundant membrane lipids, have a polar head group containing a phosphate group and two hydrophobic hydrocarbon tails.
• Phosphoglycerides, the main phospholipids in most animal cell membranes, have a three-carbon glycerol backbone and different fatty acids and head groups.
• Sphingolipids, built from sphingosine, are another important class of phospholipids and constitute more than half the mass of lipid in most mammalian cell membranes.
• Cholesterol, a sterol, is present in large amounts in eukaryotic plasma membranes, with up to one molecule for every phospholipid molecule.
• Glycolipids, sugar-containing lipid molecules, are found exclusively in the monolayer facing away from the cytosol in eukaryotic plasma membranes.
• Phospholipid molecules form bilayers spontaneously in aqueous environments, with their hydrophobic tails in the interior and hydrophilic heads exposed to water.
• Individual lipid molecules can diffuse freely within the plane of a lipid bilayer, and lipid asymmetry is functionally important in converting extracellular signals into intracellular ones.
• Many cytosolic proteins bind to specific lipid head groups found in the cytosolic monolayer of the lipid bilayer, highlighting the functional importance of lipid asymmetry.

Cell Membrane Structure and Composition

• The lipid bilayer is about 5 nm thick and forms the basic fluid structure of the cell membrane, serving as a barrier to most water-soluble molecules.
• Most membrane proteins span the lipid bilayer and mediate various functions, including molecule transport, catalysis, and structural connections.
• Approximately 30% of proteins encoded in an animal's genome are membrane proteins, essential for cell function and interaction with the environment.
• Lipid molecules, mainly phosphoglycerides, sphingolipids, and sterols, constitute about 50% of the mass of most animal cell membranes, with the rest being protein.
• Phospholipids, the most abundant membrane lipids, have a polar head group containing a phosphate group and two hydrophobic hydrocarbon tails.
• Phosphoglycerides, the main phospholipids in most animal cell membranes, have a three-carbon glycerol backbone and different fatty acids and head groups.
• Sphingolipids, built from sphingosine, are another important class of phospholipids and constitute more than half the mass of lipid in most mammalian cell membranes.
• Cholesterol, a sterol, is present in large amounts in eukaryotic plasma membranes, with up to one molecule for every phospholipid molecule.
• Glycolipids, sugar-containing lipid molecules, are found exclusively in the monolayer facing away from the cytosol in eukaryotic plasma membranes.
• Phospholipid molecules form bilayers spontaneously in aqueous environments, with their hydrophobic tails in the interior and hydrophilic heads exposed to water.
• Individual lipid molecules can diffuse freely within the plane of a lipid bilayer, and lipid asymmetry is functionally important in converting extracellular signals into intracellular ones.
• Many cytosolic proteins bind to specific lipid head groups found in the cytosolic monolayer of the lipid bilayer, highlighting the functional importance of lipid asymmetry.