Membranes Flashcards
What is the primary function of cellular membranes?
To separate the components of the cell from the outside environment
This is referred to as separating life from non-life.
What do membranes in eukaryotic cells compartmentalize?
Particular cellular spaces into organelles
What unique environment does the lysosome maintain?
pH = 5
What is the pH of most of the cell’s environment?
pH = 7.4
What structure do phosphoglycerides, also known as phospholipids, form?
A bilayer
What orientation do the nonpolar, hydrophobic tails of phospholipids take in the bilayer?
They point to the inside
What do the polar heads of phospholipids point toward?
The outside of the cell and the inside of the cell
What is critical for a cell regarding the membrane’s function?
Nutrients stay in the cell and toxic compounds stay out
What is the role of cholesterol in the membrane?
To prevent tight packing and help keep the bilayer fluid
What are sphingolipids known to aid in defining?
Blood type
What is the function of proteins in the membrane bilayer?
To help transport polar molecules across the membrane
What are integral proteins?
Proteins firmly associated with the membrane that may span the bilayer
What distinguishes peripheral proteins from integral proteins?
Peripheral proteins are loosely associated with the membrane
What is the fluid mosaic model?
A model that describes the mixture of lipids and proteins in the membrane bilayer
When was the fluid mosaic model developed?
In the 1970s
What characteristic allows individual membrane molecules to move?
The membrane is not a rigid structure but moves and flows
Fill in the blank: The interior of the membrane is composed of _______.
Lipids
True or False: The membrane is a rigid chemical structure.
False
