44 Questions
What is the primary function of compartmentalization in cells?
To separate 'self' from the environment and separate vital functions
Which of the following is NOT a function of the plasma membrane?
Photosynthesis
What is the primary purpose of the plasma membrane surrounding the entire cell?
To act as a barrier between the cytoplasm and external environment
Which of the following organelles is NOT membrane-enclosed?
Cytoskeleton
What is the role of membrane proteins in the plasma membrane?
To facilitate transport of specific molecules across the membrane
Why is it necessary for compounds to cross cell membranes?
For communication between compartments and cells
What is the function of the plasma membrane in terms of extracellular signals?
To transduce extracellular physical or chemical signals into intracellular events
What is the main function of cholesterol in cell membranes?
To alter the molecular packing of phospholipids
What is the approximate diameter of microdomains in cell membranes?
70 nanometers
What type of lipid is responsible for determining blood types?
Glycolipids
What is the primary component of phospholipid membranes?
Phosphoglyceride
What is the function of adhesion proteins in cell membranes?
To hold cells together
What is an example of a type of phospholipid?
Lecithin
What is the function of receptor proteins in cell membranes?
To recognize and bind to specific molecules
What type of molecules can pass through gap junctions?
Molecules up to 500 Da in size
What is the main difference between symport and antiport?
Symport transports molecules in the same direction, while antiport transports molecules in opposite directions
What is the primary function of receptor proteins in cell membranes?
To recognize and respond to specific signals
What type of proteins are attached to the membrane through a covalently attached fatty acid?
Lipid-anchored proteins
What is the term for the movement of molecules from an area of higher concentration to an area of lower concentration?
Diffusion
What is the purpose of cholesterol in cell membranes?
To regulate the fluidity of the membrane
What type of ion channels are generally open all the time?
Ungated ion channels
What is the term for the movement of water molecules across the membrane from an area of higher concentration to an area of lower concentration?
Osmosis
What is the main function of phospholipids in cell membranes?
To form the main component of cell membranes
What is the effect of cholesterol on the permeability of the cell membrane?
It decreases the permeability of the membrane
What is the characteristic of microdomains in cell membranes?
They are small regions rich in sphingolipids and cholesterol
What is the function of glycolipids in cell membranes?
They determine the blood type of an individual
What is the arrangement of phospholipids in the cell membrane?
They are arranged in an asymmetrical bilayer
What is the function of transport proteins in cell membranes?
They facilitate the transport of molecules across the membrane
What is the source of lecithin, a type of phospholipid?
Egg yolks and soybeans
What is a primary function of the plasma membrane?
To separate self from the environment
What is a characteristic of cell membranes?
Selective permeability
What is the purpose of compartmentalization in cells?
To separate and optimize vital functions
What is necessary for communication between compartments and cells?
Compounds crossing membranes
What is a function of membrane proteins in the plasma membrane?
To regulate the passage of molecules
What is a characteristic of eukaryotic cells?
The presence of the same basic set of membrane-enclosed organelles
What is a function of the plasma membrane in terms of extracellular signals?
To transduce extracellular physical or chemical signals into intracellular events
What is the function of transport proteins in cell membranes?
To facilitate the movement of molecules across the membrane
What type of proteins are involved in cell-cell recognition and adhesion?
Adhesion proteins
What is the function of aquaporins in the plasma membrane?
To facilitate water transport through the membrane
What is the term for the movement of ions across the membrane?
Ion transport
What type of proteins are involved in cell signaling and receiving external signals?
Communication proteins
What is the primary function of ion channels in the plasma membrane?
To regulate the movement of ions across the membrane
What is the function of gap junctions in cell membranes?
To allow the passage of small molecules between adjacent cells
What is the term for the movement of molecules from an area of higher concentration to an area of lower concentration?
Diffusion
Learn about the structure and function of cell membranes, the role of membrane proteins, and how compartmentalisation helps separate and optimise vital functions in eukaryotic cells. Discover how compounds cross membranes for communication between cells and compartments. Test your knowledge with this quiz!
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