Module 3.1 - Biomass Transport I (Fundamentals)

Question 1

Androgenesis

Answer 1

Growth of blood vessels off other blood vessels

Question 2

What happens when cells have low O2?

Answer 2

cells starving of O2 and other nutrients secrete signal molecules, which activate vessel movement/growth towards the area to feed low O2-tissue

Question 3

Why does our skin lose more moisture in the winter?

Answer 3

Amount of water in air is lower, so driving force is low. Barrier properties of skin change with moisture

Question 4

Mass transfer

Answer 4

Movement of one or more molecular species relative to others in a mixture (moving randomly)

Question 5

T/F: Diff speeds of molecules depend on their size and internal energy

Answer 5

T

Question 6

Flux of species A is given by…

Answer 6

mass: j_A = rho_A(v_A - v) = n_A - rho_A*v

mole: J_A = c_A(v_A - v) = N_A - c_A*v

Question 7

T/F: Diffusion always occurs in steady state conditions

Answer 7

F: occurs in non-ss conditions

Question 8

Diffusivity constant

Answer 8

Representation of resistance to diffusion/movement (the amount of a particular substance that diffuses across a unit area in 1 s under the influence of a gradient of one unit)

Question 9

Estimate radius of solute by assuming ________

Answer 9

Perfect sphere

Question 10

Stokes-Einstein equation assumes…

Answer 10

Solute molecules are much bigger than solvent

Question 11

Equilibrium

Answer 11

System is in equilibrium with surroundings if there is equal transfer across the boundaries (no net exchange)

Question 12

Partition coefficient

Answer 12

Describes how a solute is distributed between two immiscible solvents. Shows solubility preference/which phase is more favourable

Question 13

T/F: In liquid-gas equilibrium, air and water is extremely ideal

Answer 13

F: not ideal. Cannot use Raoult’s Law, but can use Henry’s

Question 14

Function of heart-lung machines

Answer 14

Blood is oxygenated via a polycarbonate membrane that separates blood from supply of sterile air. Used when heart stops beating and surgery must be done

Question 15

Flux across membrane driving force

Answer 15

Conc gradient

Question 16

T/F: There may be partitioning of drug into membrane, THEN movement through membrane

Answer 16

T

Question 17

Cause of stagnant boundary layers on each side of the membrane

Answer 17

Force of heat pushing molecules on either side of membrane (now technically 3 memb for solute to move through)

Question 18

T/F: If we assume infinite vol for concentration to dissolve, we’re adjusting C_A,1 and C_A,2 outside BL

Answer 18

F: If we have infinite volume for concentration to dissolve, we have constant concentrations of C_A,1 and C_A,2 outside BL

Question 19

Once inside the system, we assume everything is ______

Answer 19

Well-mixed

Question 20

Why do we assume infinite time frame of A diffusing through a membrane wall?

Answer 20

Steady state

Question 21

Microscopic species balance

Answer 21

Assumes the concentration of the species is the same everywhere in the control volume (can’t make this assumption for many physiological transport problems)

Question 22

How many boundary conditions do we need to solve Fick’s 2nd Law?

Answer 22

3: 1 IC for initial time frame or infinite cond’t, and 2 ICs for boundaries (due to double differential)

Question 23

T/F: We’re more interested in concentration profile rather than flux

Answer 23

F: opposite, flux > profile