Movement In + Out of Cells Flashcards
solute
a substance that can be dissolved
solvent
a substance that does the dissolving
solution
when the solute has dissolved and is no longer distinguishable from the solvent (a uniform mixture)
intracellular
w/in a cell
extracellular
outside of a cell
intercellular
between cells (interstitial)
What are types of PASSIVE processes?
diffusion, facilitated diffusion, osmosis, filtration
What is a passive process?
a process that doesn’t require energy needed by the cell
What is diffusion?
- is the mvmt of molecules (ions + water) from HIGH to LOW concentration
- oxygen enters the cell
- carbon dioxide leaves the cell
- occurs by simple diffusion through the lipid layer of the cell membrane
What is facilitated diffusion?
- diffusion w/ the aid from carrier proteins
- glucose enters the cell
What is osmosis?
- mvmt of water through a semipermeable membrane from LOW to HIGH solute concentration (high solvent to low solvent)
- water constantly moves in and out of the cell
What is osmotic pressure?
amt of pressure necessary to stop the flow of water across the membrane
What is filtration?
- substances are forced through a membrane by hydrostatic pressure, small solutes pass through, larger molecules don’t
- important in kidney function*
What are active processes?
processes that need energy from the cell
Examples of active processes
endocytosis, exocytosis, active transport
Endocytosis
materials taken into the cell
What are examples of endocytosis?
phagocytosis, pinocytosis, receptor-mediated
Phagocytosis
- “cell eating”
- cell membrane extends around solid particles
- some WBCs and macrophages are phagocytic
Pinocytosis
- bulk phase
- “cell drinking”
- cell membrane extends around fluid droplets
- important in absorptive cells in the small intestine
Receptor-mediated
- specialized membrane receptors bind to substances entering the cell
- enzymes, insulin, hormones, iron + cholesterol enter the cell this way
Exocytosis
- materials exit the cell
- waste products are excreted
- useful products are secreted into the extracellular space
- hormones, neurotransmitters, and mucus are released from the cell this way
Active transport
- mvmt of molecules from LOW to HIGH concentration w/ the aid of carrier proteins
What is an example of active transport?
- sodium-potassium pump (a pump w/in cells)
- most ions + AAs move INTO cells this way
Hypotonic
- extracellular fluid is LESS concentrated than intracellular fluid
- RBCs placed in a hypotonic solution gains water through osmosis which results in the cell bursting (hemolysis)
Hypertonic
- extracellular fluid is MORE concentrated than intracellular fluid
- RBCs placed in a hypertonic solution LOSES water through osmosis which results in cremate (shrivel)
Isotonic
- concentrations are equal
- RBCs remain unchanged in isotonic solution because osmotic pressures are equal
