Physical properties of life
Diffusion describes the spread of particles through random motion from regions of higher
concentration to regions of lower concentration.
Diffusion of solid in liquids: solid particles diffuse in liquid through random motion of
their particles from higher concentration into regions of low concentration.
Example: diffusion of magnesium permanganate in water.
Diffusion of gases: on the two sides of a tube, HCl & NH4OH were applied. A white ring
of NH4Cl. The white ring was formed close to HCl because HCl diffuses slower because
it has greater molecular weight than NH3 (NH3 diffuses not NH4OH).
To calculate the time of diffusion, we measure the distance traveled by the gas then
divide it on the time elapsed.
Brownian movement is the random
movement of particles suspended in a
fluid.
Osmosis is the movement of water
molecules across a selectively-permeable
membrane down a water potential gradient.
More specifically, it is the movement of
water across a selectively permeable
membrane from an area of high water
potential (low solute concentration) to an
area of low water potential (high solute
concentration).
The apparatus used to study this
phenomenon is called osmometer.
The funnel used in this experiment is called
thistle funnel.
To calculate osmosis rate, divide the amount
of water raised in the tube over the time
elapsed.
Sol- gel reversal: Agar is a powder used to produce a gel when boiled in water. The gel
formed reverse to liquid when boiled again. This process is called sol- gel reversal.
Plasmolysis is the process in plant cells where the plasma membrane pulls away from the
cell wall due to the loss of water through osmosis.
Isotonic solution: A solution that has the same salt concentration as the normal cells of
the body and the blood
Hypotonic solution: A solution with a lower salt concentration than in normal cells of the
body and the blood.
Hypertonic solution: A solution with a higher salt concentration than in normal cells of
the body and the blood.
Hemolysis: is the rupturing or openning of erythrocytes (red blood cells) and the release
of their contents (hemoglobin) into surrounding fluid.
Seed imbibition: is the adsorption of water molecules by the seed.
% Imbibition= (wet seeds- dry seeds)/ dry seeds X 100%.