HL Biology Unit 1: Water

Biomolecules: Water

cohesion

water molecules bond to other water molecules

adhesion

water molecules bond to non-water molecules

2/3

How much of the planet does water make up?

65%

How much water does a typical human body contain?

structure of water

one oxygen, two hydrogen atoms

bonds share in a polar covalent bond

polarity

slight difference in charge that occurs at different molecular poles due to unequal sharing of electrons

covalent bonds

share electrons

ionic bonds

transfer electrons

hydrogen bonds

weak polar associations that form between hydrogen and fluorine, oxygen, or nitrogen

weak by itself, but strong when there are many

solvent, cohesive, adhesive, thermal, buoyancy, viscosity, density

What are the properties of water?

solvent properties

can dissolve polar or ionic substance to be an effective medium

thermal properties

water requires a very large amount of heat energy to change state

viscosity

a fluid’s tendency to flow

a denser object is more resistant to flow

Is a denser object more or less resistant to flow?

buoyancy

an upward force applied to an object in a medium

universal solvent

water can dissolve all polar and charged substances, but not non-polar substances

water can dissolve salt until there is more salt than water

How much salt can water dissolve?

hydrophilic

“water-loving”

hydrophobic

“water-hating”

capillary action

cohesion + adhesion =

lipids, cholesterol, fat

What bodily substances can water not dissolve?

surface tension

hydrogen bonds cause cohesion. this net force results in….

hydrophobic hairs and surface tension

How do water striders stay afloat?

capillary action

What force allows water to be transported up xylem vessels in trees?

high melting point, high boiling point, high heat of vaporisation, high heat of fusion

what are the thermal properties of water?

specific heat capacity

it takes A LOT of energy to change the temperature and state of water

thermal conductivity

the rate at which heat passes through a material

blubber

what is an example of an efficient way aquatic animals retain heat?

bones are solid, but less dense

how does the black throated loon utilize buoyancy?

legs located at rear for better propulsion through water

how does the black throated loon utilize viscosity?

feathers form an interlocking barrier to limit heat loss

how does the black throated loon utilize thermal properties?

denser bones allow for prolonged submersion

how does the ringed seal utilize buoyancy?

streamlined body shape for propulsion in water

how does the ringed seal utilize viscosity?

outer fur coat and thick blubber layer

how does the ringed seal utilize thermal properties?

water is less dense as a solid

is water less or more dense as a liquid than a solid?

expands

what does water do when it freezes?

Goldilocks Zone

planets where the temperature allows it to exist in liquid state

earth is here