HL BIO UNIT A1 - WATER

metabolism

combination of all chemical reactions taking place inside organisms

medium

physical env where reactions occur: chem of life

evidence to support the theory: life originated in water (3pt)

1. all life on earth needs water to survive

2. building blocks of life are found in water

3. fossil records show evidence of ancient aquatic life (stromatolites)

is water polar or non polar

water molecules have covalent bonds however it is polar since the charges are unequal

what are hydrogen bonds

weak intermolecular forces, hydrogen attracted to electronegative molecules + between polar molecules

what is the delta symbol for (S)

indicates small charge

s+ = anion

s- = cation

what is confirmation bias

tendency to search for, interpret, and favour info/data to confirm pre existing beliefs/hypotheses

atomic structure of H20

intra vs inter

intra: within

inter: among molecules

hydrogen bond diagram

(dotted line)

cohesion

force where indv molecules of same type stick together

lets water molecules be drawn up xylem tubes in plants, high surf tension

surface tension

when molecules that are at surface of liquid, there is net inward cohesive force since no attracticr force acts from above, causes molecules to contract/resist

water cohesion creates surfacetension holding molecules of liquid tgth at surface

surface skate

waxy cuticle prevents wetting of body, mass of H20 not great enough to break

viscosity

measure of fluids resistence to flow

adhesion

force where individual molecules stick to other surfaces

hydrophilic

bonds attracted to water

capillary tubes

vertical thin channels found in soil

capillary action

• Occurs in vascular plants

• Minerals in the soil dissolve in water

• This water, containing dissolved minerals, enters the plant and moves upward

1. Adhesion → Water molecules are attracted to and stick to the walls of the xylem.

2. Cohesion → Water molecules are attracted to and stick to each other, creating a continuous column of water.

3. Upward movement → Adhesion helps water climb the xylem walls, while cohesion helps pull the rest of the water molecules upward. Together, they allow water to move against gravity.

solute

dissolved molecule or ion in solution

solvent

liquid in which another substance can be dissolved

hydrophobic

repelled by water

xylem

specialized tube functioning to facilitate movement of water thru vascular plants

vascular bundles

group of thin xylem tubes

more efficient way for adhesive forces to travel up since they are thin and numerous

buoyancy

fluid providing vertical upwards force on object placed in/on it

thermal conductivity (k)

measures how easily heat flows through metals

specific heat capacity

amount of energy to raise temp of 1kg of substance by 1 degree C

solution

mix of solute(s) dissolved in solvent

solvation

solvent with dissolved solute

hydration shell

hydrogen bond around solute