A1.1 Water Flashcards
first cells, polarity, structure, properties, origin, extraterrestrials
what did primordial earth look like?
molten mass, high temperatures, no water
how were the first cells formed on earth?
temperatures decreased, water and water cycle formed, ocean water used as solvent for biochemical reactions, cells evolved membranes to separate cytoplasm
define hydrophilic
water-loving, polar, soluble in water
what are examples of hydrophilic solutions?
cytoplasm, blood, water in xylems
define hydrophobic
water-hating, non-polar, insoluble in water
what are examples of hydrophobic substances/molecules?
steroids, cuticles
where is water found?
marine habitats, all organismal fluids, between cells
what kinds of bonds are found within and between water molecules?
polar covalent bonds between oxygen and hydrogens within molecule, hydrogen bonds between molecules
what are the charges of oxygen and hydrogen in a water molecule?
oxygen is δ-, hydrogen δ+
what are hydrogen bonds?
weak attractions caused by polarity between hydrogen and electronegative atom; ephemeral in liquid water, locked in place in solid
define cohesion
attraction between like molecules
what is surface tension?
strong cohesive force between surface molecules of water; absence of water molecules pulling upwards results in stronger force pulling downwards and laterally
define adhesion
attraction between unlike molecules
define xylem
small tubes that water travels through in plants; extends from roots, through stem, and leaves
define stomata
small openings on underside of leaf where water transpires
define tension
low pressure in area around stomata formed after water transpires
describe the process of transpiration
- water rests in place in xylem due to adhesion
- water transpires through stomata, creating tension
- cohesion causes more water to be pulled up through xylem
- more water enters xylem through roots
draw three water molecules bonded together
solid lines for covalent bonds, dotted lines for hydrogen bonds, δ- and δ+ labels on O’s and H’s in hydrogen bonds, starts forming ring shape, H’s not in hydrogen bond outside
define buoyancy
force acting on object in medium equal to weight of medium displaced by object
define viscosity
substances’ resistance to objects moving through them
define specific heat capacity
ability of substance to absorb/release heat without changing in temperature
define thermal conductivity
ability of substance to transfer heat
what are the physical properties of water?
high buoyancy, specific heat capacity, and thermal conductivity, and relatively low viscosity
how did the black-throated loon adapt to water’s viscosity?
streamlined body and webbed feet
