anatomy ch 3 lecture Flashcards
cell theory
1.) All living organisms are composed of cells.
2.) The cell is the basic unit of life.
3.) New cells arise only from pre-existing cells.
how many different cell types are in humans
over 250
three basic parts of human cells
plasma membrane
cytoplasm
nucleus
extracellular materials
substances found outside of cells
classes of extracellular materials
extracellular fluids
cellular secretions
extracellular matrix
examples of extracellular fluids
interstitial fluids
blood plasma
cerebrospinal fluid
function of plasma membrane
acts as active barrier separating intracellular fluid from extracellular fluid
controls what enters and leaves cell
structure of plasma membrane
phospholipid bilayer
membrane proteins
glycocalyx
cell junction
integral proteins
transmembrane protein
hydrophobic and hydrophilic regions
transport proteins, enzymes, receptors
peripheral proteins
loosely attached to integral proteins
on intracellular surface used for plasma membrane support
transport proteins
span membrane
provide channel across for particular solute
glycocalyx
carbohydrates sticking out of cell surface
cell recognition
allows immune system to recognize self vs nonself
what are the three ways cells can be bound together
tight junctions
desmosomes
gap junctions
tight junctions
impermeable junction
prevent fluids and molecules from moving in between cells
ex. stomach lining
desmosomes
connect cytoskeletons of neighboring cells
allow “give” between cells
ex. skin
gap junctions
transmembrane proteins from tunnels that allow small molecules to pass from cell to cell
ex. involuntary muscles
passive transport
no energy required
active transport
energy (ATP) required
plasma membrane is _____ permeable
selectively
what are the three types of passive transport
simple diffusion
facilitated diffusion
osmosis
simple diffusion
molecules move from high to low concentration
how is the speed of diffusion influenced (3)
concentration
molecular size
temperature
facilitated diffusion
molecules move down the concentration gradient through the use of protein channels or carriers
osmosis
movement of water molecules from high to low concentration across a semipermeable membrane
carriers
transmembrane integral proteins
what do carriers transport
specific POLAR molecules, too large for membrane channels
sugars, amino acids
when are carriers saturated
bound to molecules and busy transporting
channel-mediated facilitated diffusion
channels transport molecules down concentration gradient
ions, water
what are the two types of channel-mediated diffusion
leakage channels
gated channels
leakage channels
always open
gated channels
controlled by chemical or electrical signals
aquaporins
specific channels for water
osmolarity
the concentration of the total number of SOLUTE particles in solvent
T/F: osmosis results in volume changes on both sides of a semi-permeable membrane
true
hydrostatic pressure
the force exerted by water inside the cell pushing against the cell membrane.
osmotic pressure
the force that’s needed to prevent water from moving into the cell due to differences in solute concentrations.
what happens to the movement of water when hydrostatic pressure = osmotic pressure
no net movement of water
tonicity
ability of a SOLUTION to change shape/tone of cells by altering cells internal water volume
isotonic solution
same osmolarity inside and outside cell
volume is unchanged
hypertonic solution
solution has higher solute concentration than cell
water leaves cell
cell shrinks
crenation
cell shrinks
hypotonic solution
solution has lower solute concentration than cell
water enters cell
cell swells
lysing
cell bursting
what are the two major active membrane transport processes
active transport
vesicular transport
why would a cell need to use active transport
solute too large for channels
solute is not LIPID soluble
solute is moving against concentration gradient
antiporter
transport one substance OUT and one substance IN
symporter
transport TWO different substances in the SAME direction
do symporters and antiporters require energy (ATP)
yes
primary active transport
required energy comes DIRECTLY from atp hydrolysis
what are the two types of active transport
primary and secondary
secondary active transport
required energy comes INDIRECTLY from ionic gradients created ny primary active transport
what are examples of primary active transport pumps
SODIUM-POTASSIUM
calcium
hydrogen (proton)
sodium-potassium pump
NA+ out of cell
K+ back into cell
in all plasma membranes
vesicular transport
active transport involving larger particles in vesicles
endocytosis and exocytosis
endocytosis
transport INTO cell
protein coated vesicles