Membrane Structure and Function Flashcards
A fluid mosaic structure, made up of lipids that allow substances to move in and out through it
Mosaic - different types of substances giving it a mosaic appearance
Plasma Membrane Structure
The backbone of the plasma membrane is made up of a lipid bilayer, made up of polar lipids.
Which end does the hydrophilic region face?
The hydrophobic region faces which end?
The aqueous or watery end
Non polar region, non watery
What do these lipid bilayers create?
Barriers between insides and outsides of cells
Why do lipids form the basic backbone?
It does not require a lot of energy to form the bilayers
Type of molecule that is the backbone. Phosphate groups facing cytosol and extracellular fluids, makes it polar. Remove fatty acid chain with phosphate group
Phospholipid
Flat plane molecule which stiffens the plasma membrane - works well to be inserted because of shape
Cholesterol
Which part of phospholipids face the cytosol? (Aqueous part)
Phosphate groups (polar parts)
Which part of phospholipid forms the hydrophobic or interior part of the cell?
Fatty acid tails
Type of membrane protein that is embedded in the membrane, and often functions as channels
Integral Membrane Proteins
Type of membrane protein that forms the internal or external aspects of the membrane. Functions as receptors or enzymes. Don’t go across entire membrane.
Peripheral Membrane Proteins
Function of membrane is dependent upon?
Proteins.
Type of carbohydrate attachment that is a carbohydrate on a lipid
Glycolipid
Type of carbohydrate attachment that is a carbohydrate on a protein
Glycoprotein
Where are carbohydrate attachments typically located on the cell membrane?
External surface
Located within membrane, an area that is found in 20% of outer membrane sphingolipids and cholesterol, useful in cell signaling
-concentration of cholesterol is much higher in these areas.
Lipid Rafts
Specialized membrane strucure that has an actin core (microfilament) holding it in place. This structure is a fold of plasma membrane that increases the cell surface area.
Microvilli
In what type of cells are microvilli important? Where might you find them?
Absorptive. Small Intestine
What does microvilli have to help preserve its integrity?
Actin Core (microfilament)
Adhesive structure in membrane-membrane adhesions that is the glycoproteins and glycolipids
because they are polar sugars, they can interact with sugars of a neighboring plasma membrane.
Glycocalyx
The membrane-membrane adhesions (like glycocalyx) that allow for better fitting by forming groove. These are called
Wavy Contours
These provide integrity and hold adjacent cells together of the same tissue
Membrane junctions
Membrane junction that is fused protein molecules in adjacent membranes, towards the apical portion of the cell, cell that faces lumen of organ or the exterior
Very protective. Also prevent material from coming between cells and entering blood stream
Tight Junctions
Where are tight junctions typically found?
Epithelium
Tough structures made of linker protein and keratin filaments (intermediate filaments). Provide integreity to tissues by holding adjactent cells together.
Common in cells that undergo a lot of torsion
Desmosomes
Where might desmosomes be found?
Epidermis and uterus
Important structural part of membrane for communication. Proteins for hollow passageways between cells which allow materials, usually IONS to flow between cells for quick communication and action potential
Gap Junction
What type of tissues are gap junctions seen?
Cardiac muscle, smooth muscle
3 overarching functions of plasma membranes
Transport Processes
Cell to cell adhesion to form tissues
Communcation
Transport process that requires no energy to be added to a system, the process will occur on its own
Passive Transport
Type of passive transport that is due to the tendency of molecules to randomize, because of which substances will move from an area of high concentration to low. This typically happens across membranes.
Simple Diffusion