18 Questions
What is the approximate ratio of lipid molecules to protein molecules in the plasma membrane?
50:1
What is the primary function of the phospholipid bilayer in the plasma membrane?
To form a barrier between the cell and its environment
What type of lipids are found only in the layer of the plasma membrane that faces the extracellular fluid?
Glycolipids
What is the main difference between the hydrophilic and hydrophobic regions of the phospholipid molecule?
The hydrophilic region is water-loving and the hydrophobic region is water-fearing
What is the primary component of the phospholipid molecule that makes it amphipathic?
The phosphate-containing head
What is the approximate percentage of phospholipids in the plasma membrane?
75%
What is the primary function of the plasma membrane in cellular communication?
Interaction with other body cells and ligands
What is the main cation present in the extracellular fluid (ECF)?
Na+
What is the term used to describe the difference in chemical compositions between the cytosol and the ECF?
Electrochemical gradient
What is the primary function of selective permeability of cell membranes?
Control of what enters and leaves the cell
What is the main anion present in the cytosol?
Both b and c
What is the purpose of maintaining an electrochemical gradient across the cell membrane?
To separate the cellular contents from the ECF
What is the main difference between integral and peripheral proteins?
Integral proteins extend across the phospholipid bilayer.
What is the function of some integral proteins that act as channels?
To allow certain substances to flow into or out of the cell.
What is the primary function of transporter proteins?
To move substances from one side of the membrane to the other.
What is the orientation of the sugar portion of a glycoprotein?
Faces the ECF.
What determines the functions a cell can perform?
The type of membrane proteins present.
What is the function of some integral proteins that serve as recognition sites?
To act as receptors.
Learn about the fluid mosaic model of membrane structure, its molecular arrangement, and the composition of plasma membranes in animal cells. Discover how proteins and lipids interact and form the cell membrane.
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