4.2 Cell Membrane Structure Flashcards
Selectively Permeable is…….
When the cell “selects” what materials enter or exit the cell through the membrane.
What other thing does the membrane help to do?
The membrane also helps to regulate (control) homeostasis by “controlling” entry or exiting of certain molecules.
stable internal environment
homeostasis
What makes up the majority of the membrane?
Phospholipids
These are amphipathic molecules. (It means there is a hydrophilic and hydrophobic component.)
Phospholipids
Hydrophilic means:
”water loving”, attracted to. “Hydro” means “water”.
Hydrophobic means:
”water fearing”, repels from
These molecules create the bi-layer and the structure is held intact by the presence of water outside and inside the cell. The negatively charged phosphorus line up to make a barrier preventing water from forming hydration shells around the phospholipids and thereby dissolving the membrane.
Yeah….
Two types of proteins are present on the membrane:
Integral
Peripheral
What do Integral proteins do?
Integral – These run completely through the bi-layer from the outside to the inside.These function in the transport of molecules and foundation. (Help to maintain the integrity of the structure.)
These are located on one side of the membrane. (They do not extend into the bi-layer of the membrane.
Peripheral
The proteins of the cell membrane can have several functions. Name 6 functions
Molecule transport
Act as enzymes
Cell to cell communication and recognition
Signal Receptors
Intercellular junctions
Attachment points for the cytoskeleton and ECM
Molecule transport
Helps move food, water, or something across the membrane.
Act as enzymes
To control metabolic processes.
Cell to cell communication and recognition
So that cells can work together in tissues.
