lec 2 Flashcards
what is surface tension due to? what is an example of an animal that has adapted to this?
surface tension is due to hydrogen bonds.
ex incl mosquitos and jesus christ lizard
water absorbs a great deal of heat due to bonds. what are some practical applications of this?
- sweat
- storing heat (polar bears)
- releasing heat (camels)
fill a bottle 70% up with water. squeeze the bottle. if water is incompressible, why it do that?
the volume of water doesnt change, just the pressure
illustrates the key principle of water being incompressible
how do organisms adapt living in deep water? what happens when we humans just deep dive?
we get things like the bends, where nitrogen gets compressed in our blood in the depths and expands as we rise, damaging joints
organisms have many adaptations (see biol 361 lecs)
how do animals navigate existing in water?
water is a fluid u need to move through –> requires energy (Re etc)
what happens to ions in water? even fresh water? why?
ions dissolve pretty readily due to their polarity, even in fresh water
what happens to the volume of water when u add in salt?
volume does not increase but fluid mass does - thought to be because the water arranges itself around ions, since water is polar
irl we have channels that transport sodium, as well as channels that transport sodium and water together. which would require more energy, and why?
assuming we’re talking about a cell suspended in water with dissolved salts, the solo sodium transport requires more energy since energy must be put in to first break the polar bonds between sodium and water.
what does the tetrodotoxin do ?
FUCK THIS DUDE BRO
okay so it mimics sodium ions, such that it fucks up (blocks? outcompetes?) sodium channels, inducing paralysis.
oil and water don’t mix. why?
fats are not polar
what is the equation for making bicarbonate? (u should know this from biol 361)
CO2 + H20 <–> H2CO3 <–> HCO3- + H2+
da H2CO3 is the bicarbonate
what is the difference for concentrations of ions between saltwater and freshwater for:
- sodium (Na+)
- chloride (Cl-)
- bicarbonate (HCO3-)
sodium and chloride have overwhelmingly higher concentrations in seawater, as do most other ions. however, bicarbonate remains largely similar [attributable to dissolving of CO2?]
what is a salt wedge? how do animals who experience salt wedges deal with them?
salt wedges aka haloclines are gradients going from saltwater to freshwater. these can often be seen in estuaries.
often, animals who live in these areas drink freshwater but not saltwater, since saltwater would throw off their osmolarity.
key thing to remember is that everything wants to move DOWN the gradient, never up it
what is the difference between molarity and osmolarity? if i add 1 mole of NaCl to water, what happens to molarity? osmolarity?
molarity (M) is the concentration of something pure in solution
osmolarity (Osm) is the concentration of all things in solution, measuring the aggregate effects of all solutes in a solution.
ex. i add 1 mole of NaCl to water.
M = 1, Osm = 2
Osm matters bc each ion exerts some pressure, so we want to account for it.
