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21 terms

Chapter 7: Cell Physiology

STUDY
PLAY
physiology
(how it works)
study of biological function
homeostasis
ability to maintain constant internal balance regardless of the environment (steady state)
-occurs at all levels
-cells exist in fluid environment
-cells must keep cytoplasm
4 factors decide what go through (homeostasis)
-size
-cell membrane
-dissolves in water
-conditions inside & outside the cell
At cellular level, homeostasis depends on movement....
in & out of the cell
-all things must pass through cell membrane
permeable
can pass through
impermeable
can't pass through
cell membrane is....
selectively (chemical) and semi-permeable (size, charge)
passive transport
energy is not required for substances to pass in and out of the cell
diffusion
moving particles from high to low concentration
-possible because of kinetic energy (energy of motion) atoms move in a straight line
-atoms keep moving til their spread evenly
Factors that affect rate of diffusion
-concentration
-pressure
-temperature
osmosis
movement of water (diffusion)
-call can't control osmosis - it moves on it's own
isotonic solution
some inside & out
-no net water movement
hypertonic solution
higher outside the cell
-water moves out
hypotonic solution
lower outside the cell
-water moves in
tugor pressure
pressure exerted by cell contents against the cell wall
-helps support soft tissue
plasmolysis
loss of tugor pressure
-causes cell contents to shrink away from the cell
cytolysis
bursting of cell from water pressure inside
active transport
energy required, low to high.
endocytosis
moves molecules and particles into the cell
-phagocytosis - cytoplasm surrounds the particles
-pinocytosis-collects on the cell membrane and pinches inward
exocytosis
large particles shipped out by golgi apparatus
Passive & active transport...
of materials through the cell membrane are ways cell maintains homeostasis