62 terms

Chapter 5 Bio Test

passive transport
substances crossing the cell membrane without any input of energy from the cell
simplest type of passive transport
movement of molecules from an area of high concentration to an area of lower concentration (down the concentration gradient)
concentration gradient
difference in concentration of molecules across a distance
constant motion from kinetic energy that move randomly - travel in straight lines until they hit something (another molecule) and bounce off in another direction - tend to move away from more concentrated area and 'up' the concentration gradient
the concentration of molecules is the same throughout the entire space - random movement of molecules continues
simple diffusion
if a molecule can pass through a cell membrane it diffuses from a higher concentration on one side to a lower concentration on the other
diffusion depends on
size and type of the molecule and the chemical nature of the cell membrane
molecules that pass through the membrane
they can diffuse lipids or they are small and pass through pores (proteins)
a solution
a solute dissolved in a solvent
material the gets dissolved
material that makes a solute dissolve
the process in which water molecules diffuse across the cell membrane (higher to lower) in passive transport
net direction of osmosis
depends on the relative concentration of the solutes on the two sides of the membrane
cell transport
movement of material across the cell membrane
diffusion is driven by
molecule's kinetic energy
difference between osmosis and cell transport
water across the cell membrane versus material across the cell membrane
a cell increasing in size until it bursts
a cell shrinking in size
facilitated diffusion
requires carrier protein that acts a a funnell
passive transport
requires no energy from the cell
electrically charged atom
another name for an ion
ions are used in
muscle contraction and nerve impulses
important ions
sodium (na)
potassium (k)
chlorine (cl)
calcium (ca)
ion channel passageways
some remain open and some open and close, passive transport, specific channels for specific ions
active transport
requires energy and ATP from the cell
goes against the concentration gradient
active transport direction
sodium-potassium pump
requires a carrier protein that transports materials against the concentration gradient
phosphate ion
changes the carrier proteins shape
water diffuses into the cell until equilibrium
water diffuses out of the cell until equilibrium
concentrations of solutes out and inside the cell are equal, the outside solution is considered isotonic
water diffuses in this pattern
hypotonic to hypertonic
if an external solution is hypotonic
that makes the cell hypertonic
unicellular freshwater organisms
function in a hypotonic environment, must sometimes get rid of excess water after osmosis
contractile vacuole
pumps excess water and solute out of cells and works in active transport
most plants cells and animals cells
live in a hypotonic environment
water enters plant roots to feed plants
a form of osmosis in plants
turgor pressure
pressured water molecules push on the cell wall
hypotonic environment osmosis
water enters the cell
hypertonic environment osmosis
water leaves the cell
reverse osmosis
water molecules move from a concentrated solution to a dilute solution
used to purify polluted water
reverse osmosis
stimuli to open ion channels
stretching of the cell membrane
electrical signals
chemicals in the cytosol
external environment
cell membrane pumps
carrier proteins are also known as
supplies energy for active transport
active transport types
the process of cells ingesting...
external fluid
large particles
other cells
endocytosis wastes
end up in membrane pockets the pinch off and become vacuoles
types of endocytosis
transports solutes or fluids
the movement of large particles or cells, ingests viruses and bacteria
phagocytosis is responsible for
feeding unicellular organisms
help fuse lysosomes with vesicles and aid in breaking down the cell membrane
a substance is released from the cell through a vesicle that fuses to the cell membrane and releases the internal substances. useful in disposing of wastes
exocytosis is basically
reverse endocytosis
protein process
proteins are made on ribosomes and packaged into vesicles by the golgi apparatus. these proteins then move to teh cell membrane and fuse with it
cells in nervous and endocine systems
use exocytosis to release small molecules that control other cells activities
ATP stands for...
adenosine triphosphate
why ATP change to ADP
the phosphate detaches from the carrier protein
ability for an organism to maintain a stable internal environment