Concept 2 Flashcards
what is the difference between dynamic and static equilibrium? (with regards to homeostasis)
a dynamic equilibrium is maintained and the conditions stay within a range, static equilibrium happens afterwords when the system has stopped and is at rest.
what is the relationship between a response to stimuli and homeostasis?
homeostasis is the need of an organism to stay stable by regulating internal conditions, stimuli is a change in environment. the response is what happens as a result to the stimuli and the organism trying to maintain homeostasis.
what is the difference between positive and negative feedback loops?
positive feedback loops: the output of the system intensifies the response (ex. human childbirth, fruit ripening)
negative feedback loops: a counter response is triggered to get the system back to a set point (ex. human body temperature, blood sugar regulation)
what is the role of the cell membrane in maintains homeostasis on a cellular level? what substances can and cannot pass thru easily?
the cell membrane controls what goes in and out of the cell. is is selectively permeable. small, hydrophobic, and/or neutral items can pass through easily. polar or larger molecules cannot.
what’s the difference between passive and active transport?
passive transport doesn’t require extra energy, while active transport does. passive transport moves molecules down the concentration gradient, while active transport does the opposite.
what are the 6 types of transport and what molecules are used? (describe)
simple diffusion
- spreading out of molecules until equilibrium is reached (move from high to low concentration)
- ex. O2 and CO2
facilitated diffusion
- transport protein(like a channel) helps facilitate the diffusion of molecules that normally couldn’t pass thru the membrane
- ex. large molecules (glucose$ and polar molecules (CA+2)
osmosis
- simple diffusion of water across the membrane, water molecules move down a concentration gradient from high to low area until equilibrium is reached
molecular pumps
- when a cell uses energy to pump molecules across the membrane, against the gradient through a protein channel
- ex. potassium K+, chlorine Cl-, sodium Na+
endocytosis
- uses vesicles to move large particles into the cell (phagocytosis, cell eating; pinocytosis, cell drinking)
exocytosis
- uses vesicles to export materials OUT of the cell
what is the difference between hypotonic, isotonic, and hypertonic solutions?
hypertonic: water is lower than the cells cytoplasm, cell shrivels
hypOtonic: water is higher than the cells cytoplasms, cell swells
isotonic: equal water to cytoplasm, cell stays the same
what is homeostasis?
need of an organism to stay stable by regulating internal conditions
what is a solute?
what gets dissolved (ex lemonade powder)
what is a solvent?
does the dissolving (ex water)
what is a solution?
uniform mixture of 2 or more substances (ex lemonade)
what is concentration?
amount of solute dissolved in the solvent (symbol for abbreviation: [ ])
what is the concentration gradient?
the difference in concentration of substance from one location to another
what is phagocytosis?
in endocytosis; cell eating
cell engulfs particle into visible and digests them
what is pinocytosis?
in endcytosis; cell “drinking”
cell engulfs liquids into vesicles and digests them
