Chapters 3.2, 4, 6 Flashcards
What is the plasma membrane?
a fluid lipid bilayer embedded with proteins. Separates the intracellular and extracellular fluid.
What are lipid anchored proteins?
proteins that are attached to the lipids by covalent bonds.
What are channel proteins?
allow water soluble compounds to pass through the lipid bilayer.
have the ability to select what passes through them based on size, charge, etc.
can also open or close, dependent upon whether a ligand is present or the charge across the membrane.
What are carrier proteins?
transport water soluble substances across the membrane.
highly selective.
What are membrane-bound enzymes?
control reactions on either inner or outer surface.
What are membrane receptors?
recognize and bind to ligands.
the ligand-receptor complex can either alter the activity within the cell, open a ligand-gated channel or promote the endocytosis of another molecule.
What are docking proteins?
inner membrane proteins for secretory vesicles and initiating exocytosis.
What are CAMs?
cell adhesion molecules. bind with other molecules on other cells to allow the cells to stick to each other.
What are glycoproteins?
located on the outer surface of the membrane only.
MHC
self vs. nonself.
How are cells held together?
collagen
elastin
fibronectin
Describe collagen
protein that provides resistance to longitudinal stress
Describe elastin
protein that provides elasticity
Describe fibronectin
protein that provides cell to cell adhesion
What makes up the extracellular matrix?
fibroblasts, which secrete collagen, elastin and fibronecti.
Describe desmosomes.
adhering junction
formed by fibers
found in organs that have a high level of stress, such as skin, heart muscle and uterus.
Describe tight junctions.
join sheets of epithelial tisse (forms highly selective barrier).
junctions are impermeable so substances do not slip between cells.
found in the lining of the stomach, intestines, etc.
Describe gap junction
a communicating junction between cells.
allows ions to travel from cell to cell
found in heart muscles and smooth muscle.
What molecules undergo diffusion?
lipid soluble substances (nonpolar) and small ions.
What can be said about molecules in high concentration solutions?
they collide with each other and thus are more likely to be moving in any direction at any time.
What is Fick’s law of diffusion?
Q=[dC]*[P]*[A]
---------------
Sqrt[MW]*[dX]
q=net rate of diffusion
dC=concentration gradient
P=permeability
A=surface area of membrane
dX=thickness of the membraneWhat is osmotic pressure?
when there are solution on both sides of a membrane, but it is not permeable to the particles in the solution. Water moves from one side of the membrane to the other until concentrations of water are equal on both sides.
What solution will have greater osmotic pressure?
the solution with the most water attracting solutes.
What is osmolarity?
Osmolality is a property of a particular solution and is independent of any membrane.
What is tonicity?
Tonicity is a property of a solution in reference to a particular membrane.
