Concept 2: Cell Transport Flashcards
Define homeostasis
stable internal conditions
Define dynamic equilibrium
not exactly the same, but within a certain range
Name the three aspects of homeostasis
pH, temperature, blood sugar
Name the three desired values for homostasis
pH of 7, 98.6ºF, ~100mg blood sugar
Define hyperglycemic
high blood sugar
Define hypoglycemic
low blood sugar
Define stimulus (plural “stimuli”)
changes in environment
Define response
the response to stimuli
Define feedback mechanism
cells/your body maintain homeostasis as they receive stimuli
Give the structure for a feedback loop
input ==> system ==> output ==> input ==> etc.
Define positive feedback loop
the output intensifies the response
Give an example of positive feedback loops
fruit ripening
fruit ripens –> fruit releases ethylene –> ethylene signals other fruit –> other fruit ripens –> etc.
Define negative feedback loop
the output causes a counter response to the system
Give an example of a negative feedback loop
thermoregulation
blood vessels go thick and go thin
Which organelle is the main cause of homeostasis at a cellular level?
cell membrane
Define semi-permeable
selective permeability
What can pass through the cell membrane?
small things
non-polar/hydrophobic things
neutral (specifically water)
What can’t pass through the cell membrane?
large things
polar/hydrophilic things
Define passive transport
things are transported in and out of the cell w/o using energy
Define active transport
things are transported in and out of the cell using energy
Define equilibrium
equal concentration between two sides
What does ATP stand for?
adenosine triphosphate
Define solute
the thing that is being dissolved
Define solvent
the thing that is dissolving
Define solution
the solute + the solvent
Define concentration
the amount of solute in the solvent
What is the symbol for concentration?
[]
Define concentration gradient
difference in concentration from one location to another
Give an example of a concentration gradient
hot chocolate
Define simple diffusion
molecules are spread across the membrane until there is equilibrium
What are the most common molecules that experience simple diffusion?
Oxygen, Carbon Dioxide
Define facilitated diffusion
molecules are spread through a transport protein until there is equilibrium
Define osmosis
diffusion of water across the cell membrane
Define hypertonic
the cell has a higher concentration of water than its surroundings
Define isotonic
the cell has an equal concentration of water than its surroundings
Define hypotonic
the cell has a lower concentratin of water than its surroundings
Define molecular pump
uses energy to go against the concentration gradient through a protein channel
What are the most common elements/molecules in molecular pumps?
K+, Cl-, Na+
Define endocytosis
moving large molecules into the cell
Define exocytosis
move large molecules out of the cell
How does endocytosis work?
The large molecule approaches the cell membrane, and the cell membrane wraps around it, forming a vesicle in the cell
How does exocytosis work?
The vesicle approaches the cell, and the vesicle merges with the cell membrane, releasing the contents of the vesicle
Name the two types of endocytosis
phagocytosis
pinocytosis
Define phagocytosis
endocytosis with solids
Define pinocytosis
endocytosis with liquids
