Cell Membrane Flashcards
What is the plasma membrane?
Thin barrier separating inside of cell (cytoplasm) from outside environment
What are the three main functions of the plasma membrane?
- Isolate cell’s contents from outside environment
- Regulate exchange of substances between inside and outside of cell
- Communicate with other cells
What does the Fluid Mosaic Model describe?
The structure and function of cellular membranes
What is a phospholipid bilayer?
Double layer of phospholipids with hydrophilic ends forming outer border and hydrophobic tails forming inner layer
What is the nature of the lipid tails in phospholipids?
Unsaturated (C = C)
What are transport proteins?
Proteins that regulate movement of hydrophilic molecules through the membrane
What are channel proteins?
Type of transport protein that allows specific ions or molecules to pass through the membrane (e.g. Na+ channels)
What are carrier proteins?
Type of transport protein that assists in the movement of larger molecules (e.g. glucose transporter)
What are receptor proteins?
Proteins that trigger cell activity when a molecule from the outside environment binds to them
What are recognition proteins?
Proteins that allow cells to recognize and attach to one another
What are glycoproteins?
Proteins with attached carbohydrate groups
What is concentration in terms of molecules?
Number of molecules in a given unit of volume (e.g. grams/liter; moles/liter)
What is a gradient?
Difference between two regions of space that causes molecules to move from one region to the other
What is diffusion?
Movement of molecules from an area of high concentration to an area of low concentration
What factors affect the rate of diffusion?
- Concentration gradient
- Molecule size
- Lipid solubility
What is passive transport?
Movement of substances across membranes that requires no energy
What is simple diffusion?
Movement of small molecules directly through the phospholipid bilayer (e.g. CO2, H2O, O2)
What is facilitated diffusion?
Movement of molecules that require assistance from channel or carrier proteins (e.g. ions, amino acids, sugars)
What is osmosis?
Movement of water from an area of high concentration of water to an area of low concentration of water across a semi-permeable membrane
True or False: Diffusion can move molecules rapidly over long distances.
False
