2 - Nerve & muscle part one Flashcards
phospholipid bilayer definition
two layer orchestration of phosphate and lipid molecules that form a cell membrane
what model in important for neurotransmission?
fluid mosaic model
What is polar and non polar in the plasma membrane?
head is polar and tail is non polar
What does the head of the phospholipid molecule contain? And how does it react with water?
Contains a phosphate group which makes is hydrophilic
hydrophilic definition
water loving
hydrophobic definition
water hating
why is the head of the phospholipid polar?
because the phosphate group is negatively charged
what does the tail of the phospholipid molecule have and it’s reaction to water?
lipid (fatty acid) and hydrophobic
the tail of the phospholipid molecule is ——
non polar
how do the 2 layers of phospholipid molecules sit?
heads face outwards - one to extracellular fluid and other head faces the intracellular fluid
Integral membrane proteins are located where?
permanently embedded within the plasma membrane
Integral membrane proteins can be classified in 2 ways
Transmembrane proteins and Integral monotopic proteins
Transmembrane proteins location in the membrane and where it’s found
span the entire plasma membrane - found in all types of biological membranes.
Integral monotopic proteins location
permanently attached to the membrane from one side
peripheral proteins are —- and attached to?
temporarily attached to the cell or membrane
peripheral proteins can be
enzymes, involved in attachment functions and shape changes
integral membrane protein location and function?
span the whole membrane, responsible for transport and communication
cytoskeleton function & location
anchors to plasma membrane, can interact with receptors
cytoskeleton definiton
interlinking protein filaments present in the cytoplasm
glycocalyx make up & location
an ensemble of carbohydrates attached to lipids and proteins on the extracellular face
what happens to the glycocalyx when the cell becomes cancerous?
changes - can change so much to avoid recognition by immune system
cholesterol (overall) function
reduces general membrane fluidity and stabilizes its structure
too much cholesterol causes membranes to?
lose flexibility
functions of plasma membrane proteins
transport, enzyme activity, receptors for signal transduction, intercellular joining, cell-cell recognition, attachment to ECM
ECM definiton
extracellular matrix, protein complex outside the cell
tight junctions contain
interlocking junctional proteins and space between cells
tight junction function
forms continuous seal on cell to precent molecules from passing between cells
desmosomes contains
space between cells, plaque, linker proteins, intermediate filament
what is the liner proteins in desmosomes?
cadherins
what is the intermediate filament made up of in desmosomes?
keratin
desmosomes function
bind adjacent cells together to prevent tearing
desmosomes can be compared to
Velcro
tight junctions have —– junctions
impermeable
desmosomes have —– junctions
anchoring
gap junctions have —— junctions
communicating
gap junction have
space between cells and channels formed by connexons
connexins is an assembly of
six proteins
gap junctions function
allow ions and small molecules to pass cell to cell
for which cells are gap junction important?
heart and embryonic
concentration gradient
a difference in concentration (high to low) `
simple diffusion
the process where a substance moves through a semipermeable membrane or in a solution without any help from transport proteins
osmosis
movement of water molecules from a solution with a high concentration of water molecules and low solute to a solution with a lower concentration of water molecules but more solutes
osmosis generally happens when the membrane is impermeable to —
solutes
isotonic solutions in cells
cell size is normal, same water/solute concretion as inside cells - water moves in and out
hypertonic solutions in cells
cell shrinks, loses water by osmosis
hypertonic - solute/water concentration inside and outside cell
extracellular fluid contains higher concentration of non-penetrating solutes than inside the cell
hypotonic - solute/water concentration inside and outside cell
extracellular fluid contains a lower concentration of non-penetrating solutes than intracellularly
hypotonic solution cell
cell grows due to intake of water through osmosis - cell can burst
transmembrane transport examples
simple diffusion, carrier-mediated facilitated diffusion, channel-mediated facilitated diffusion and osmosis
