18 Questions
What contributes to the mechanical strength of the plasma membrane?
Cholesterol
What is the main role of proteins in the plasma membrane?
Transfer information
How are the two layers of phospholipids arranged in the plasma membrane?
Nonpolar tails meeting in the center of the membrane
What prevents phospholipids from moving around too much in the plasma membrane?
Cholesterol
In the fluid mosaic model, what does 'fluid' refer to?
Free movement of proteins within the membrane
Which component of the plasma membrane helps anchor proteins within it?
Cholesterol
What is the main reason for most cells maintaining a certain shape?
Supporting network of fibers inside the cell
What term is often used to describe the plasma membrane of animal cells?
Fluid mosaic
How are proteins in the plasma membrane described in the text?
Floating like icebergs in a sea of lipids
The plasma membrane of animal cells is not rigid because it is constantly undergoing what type of change?
Structural rearrangement
What does the 'fluid mosaic' model imply about the structure of the plasma membrane?
It is constantly changing and dynamic
Which component of the cell primarily limits cell shape according to the text?
Fluid within the cell
How do plasma membrane proteins generally interact with water?
Charged regions extend out of the membrane and are in contact with water.
What function do some membrane proteins serve in relation to the cell's structure?
Anchoring the cell's internal scaffold-like support network
How does the plasma membrane create a barrier between the cell's external environment and its internal processes?
By selectively permitting entry of necessary materials and ions
Which process involves molecules crossing the plasma membrane without requiring energy input?
Diffusion
What characterizes membrane proteins that span the entire plasma membrane?
They have both electrically neutral and charged regions.
Which component contributes to the rigidity of the cell membrane?
Cholesterol
This quiz covers the structure of the plasma membrane in biology, focusing on the lipid bilayer, cholesterol and proteins that make up its composition. Topics include phospholipids, cytoskeleton, and the functional properties of the plasma membrane.
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