Module 7 Flashcards
Cell Membrane & Trans-Membrane Transport
what are the functions of the plasma membrance
a physical barrier, selective permeability, communicate, signaling, and electrochemical gradient
what is the function of a physical barrier
separating the intra and extra-cellular fluid compartments and activities
what is the function of selective permeability
to decide what goes in the cell and when
what is the function of communication
to allow cell-to-cell recognition
what is the function of signaling
cells respond to or send out signals to modify other cells for maintaining homeostasis
what is the function of electrochemical gradient
excitability
what is the ‘model’ name describing plasma membranes
the fluid mosaic
what is the term for inside the cell
intracellular
what is the term for outside the cell
extracellular or interstitial (between cells)
why don’t we call the plasma membrane a cell wall
Cell wall is only found in plants where plasma membrane is found in all living organisms including plants
what are the lipid types found in the plasma membranes
phospholipids, glycocalyx, cholesterol, and lipid rafts
what is the function of phospholipids
structural
what is the function of glycocalyx
identify self from self, decorating the outside, how you are recognized
what is the function of cholesterol
protects the cell and keeps it fluid when it wants to freeze
what is the function of lipid rafts
holds proteins
what are the functions of membrane proteins
transport, receptors, structure, and enzymes catalyze cellular responses to various signals
what are transports
channels and transporters
what are receptors
responding to extracellular chemical signals
what are structures
stability, intracellular cytoskeleton ‘anchors’ - intercellular connections
what are the functions of membrane carbohydrates
cell-to-cell recognition and interaction, identification and communication
what protein function would permit Na+ ions to enter the cell
channel transporter
what would respond to a hormone signal
receptor
what kind of membrane modification increases surface area
microvilli
what is microvilli
extends the surface and increases cell membrane surface area
what kind of membrane modification sweeps mucus over the cell surface
cilia
what is cilia
sweeps the materials off the cell surface, keeps it clean
what are the three types of cell junction
tight junction, desmosomes, gap junctions
what is the function of tight junction
keeps stuff from slipping between the cells
what is the function of desmosomes
distributing tension to keep cells from tearing apart
what is the function of gap junctions
allowing chemicals to flow from cell to cell, communicate
what is the difference between semi and selective permeability
semi- some things are capable to trans-membrane movement and others aren’t
selective- the ‘permission to access’ is selective to meet the needs of the cell, depend on what the cell needs
what kinds or solutes are freely permeable at all times
O2, CO2, and H20, lipids that are either non-polar and/or small
what kinds of solutes need protein channels
simple sugars and amino acids
when there is a difference in concentration between the inside and outside of a cell it is called a
gradient
what are gradients
potential energy
define the difference between chemical, electrical, and temperature
chemical- between molecule types
electrical- between ionic charges
temperature- between heat inside the cell and outside the cell
what kind of energy moves solutes during diffusion and facilitated diffusion transport
potential energy
what kind of energy moves solutes during active transport
cellular energy input or ATP
how does osmosis differ from diffusion and active transport
water is moving to break up solutes, impermeable to solutes
moves from lower to higher solute concentrations
water follows solute
what does osmolality measure
solute concentration of a solution
how does osmolality different from hydrostatic pressure
hydrostatic pressure forces fluid out of the capillary
osmotic pressure draws fluid back in
what happens to cells when it is exposed to Isotonic solutions
solute concentration equal on both sides of membrane, concentration on inside and outside is the same
what happens to cells when it is exposed to Hypertonic solutions
solute concentration less than inside cell, water is going to move into the cells and burst
what happens to cells when it is exposed to Hypotonic solutions
solute concentration more than inside cell, outside is too much and leaves the cell, shrink
