13-15;Fick's/Osmosis/Transport/Cohesion/Surface tension

Question 1

describe the kinetic energy of molecules

Answer 1

at ordinary room temp, solids, liquids and gases move continuously at v high speeds

gas=make billions of collisions w/ walls each sec = causes P of gas on walls of container

liquids=move about w/ mutual attraction but no preferred order

solids= molecules vibrate back and fourth rapidly in their limited space

liquids and solids motion of molecules is limited by mutual attractive forces and less empty space for movement

Question 2

random kinetic energy

Answer 2

energy that accomplishes net transfer of molecules

Question 3

osmosis

Answer 3

diffusion of solvent across semi-permeable membrane, down conc gradient

Question 4

semi permeable membrane

Answer 4

membrane permeable to solvent molecules, blocks passage of solutes

Question 5

osmotic pressure

Answer 5

pressure required to prevent diffusion from pure sol into that sol

net migration of solvent molecules yields difference in height proportional to osmotic pressure diff

Question 6

hypertonic

Answer 6

sol is less conc, cell is more conc so water moves out of cell, shrivels, dies

Question 7

hypotonic

Answer 7

sol is more conc, cell is less conc, water moves into cell, swells and dies

Question 8

dialysis

Answer 8

process involving diffusion of several types of molecules through a selectively permeable membrane

mostly in kidneys of removal of water from blood in nephrons

Question 9

dialysis in kidneys

Answer 9

via nephrons to remove water from blood, 2 main parts: glomerulus and bowman’s capsule

glomerulus is coiled shape of thin-walled capillaries enclosed by bowman’s capsule, water reabsorption is process is via GLOMERULAR FILTRATION

Reabsorption proceeds by DIFFUSION = dialysis

Question 10

dialysate

Answer 10

controlled sol of electrolytes

often subjected to -ive P to speed removal of XS water from blood

regulate so osmotic P diff across membrane isn’t too large

Question 11

AT

Answer 11

Molecules transported against conc gradient, required ATP

Question 12

are selectively permeable membranes subject to +ive or -ive pressure

Answer 12

+ive BP to force plasma out

Question 13

describe molecular transfer across capillary system

Answer 13

outflow from capillary on arteriole end is almost balanced by return on venule end = maintain almost constant vol of circulating blood

more slight outward XS = balanced by fluid return via lymphatic circulation

Question 14

blood molecules and effect on osmotic pressure

Answer 14

blood albumin = large molecule stays in capillaries to contribute osmotic P diff

loss of albumin = more fluid leaves capillaries in arteriole end, less return in venule end = oedema = collection of fluid in tissues

loss of salt = blood and interstitial fluid becomes hypotonic = water diffuses into cells = depletes interstitial fluid

Question 15

cohesion vs adhesion, give EG

Answer 15

cohesion = strong internal attractive forces between like molecules, 
adhesion= forces between unlike molecules

EG curved surface of WATER meniscus, curved up = water molecules at edge adhere to glass wall more strongly than they cohere to each other.

of MERCURY Curved down = since cohesion atoms stronger than adhesion to wall

Question 16

surface tension

Answer 16

cohesive forces between liquid molecules more strongly those on surface = forms shape of liquid droplets of a spherical shape

Question 17

how does surface tension affect function of liquid

Answer 17

high surface tension = water can be nebulised/placed in aerosol form

low surface tension = good cleansing agent = spreads out and wets surface readily == hot water is better cleaning agent than cold water = hotter = molecules more agitated at surface = reduces cohesive forces = lower surface tension

Question 18

why is surface tension needed in respiration

Answer 18

provides necessary membrane strength to maintain the bubble like alveoli, where oxygen exchange from air to blood occurs.

T=Pr/2
if T increases=more P needed to keep radius same otherwise bubble collapses
If P is constant and r decreases = bubble is unstable = collapses
If r increases too much and P isn’t enough to stabilise it = will rupture since required T is too great

Question 19

what is the challenge for newborn baby relating to laplace law

Answer 19

premature infants haven’t developed a sufficient amount of needed surfactant layer on alveoli, so as r increases = surfactant layer gets thinner = tension will halt expansion

also when r gets smaller = surfactant gets more conc on surface = lowers T = halts expansion

so exhaling is done by the elastic recoil of chest, helped by the deflation of alveoli = decreased r = increased T

Question 20

capillary action

Answer 20

ability of liquid to flow in narrow spaces w/o assistance of gravity, result of adhesion and surface tension

Question 21

viscosity

Answer 21

determines flow rate of fluid through tube due to internal friction due to mutual cohesive forces of fluid molecules

Question 22

adsorption

Answer 22

molecular attractive force that causes outside substances to attach to liquid/solid

Question 23

absorption

Answer 23

when outside substances penetrates into substances EG gas/liquid condenses and attaches to surface of solid