Anatomy and Physiology 1

1/ What is the driving force in the diffusion?
Randomness. As far as forces go i believe you can end up with a pressure if you have two different concentration on opposite sides of a membrane. Cells have been know to explode as a result of this effect. Wikipedia.org, "The World's Encyclopedia" really says it best Search 'Molecular diffusion" "Molecular diffusion, often called simply diffusion, is a net transport of molecules from a region of higher concentration to one of lower concentration by random molecular motion. The result of diffusion is a gradual mixing of material. In a phase with uniform temperature, absent external net forces acting on the particles, the diffusion process will eventually result in complete mixing or a state of equilibrium. Basically, it is the movement of molecules from an area of high concentration to a lower area."
2/ In diffusion, molecules move : a from high concentration to low concentration.
3/ Which of the following dialysis membranes has the largest pore size?
MWCO in terms of pore size : the larger the MWCO number, the larger the pores in the membranes.
4/ Avogadro’s number is a constant for the number of : molecules

Experiments 20 MWCO : Na+Cl- no diffuse ; Urea no diffuse (9.00 mM)
1/ The reason sodium chloride didn’t diffuse left to right is that : - the membrane pore size was too small
2/ The molecular weight of urea is 60.07 . Do you think urea will diffuse through the 20 MWCO membrane? No, not at all ( Predict Ques. 1)
3/ Glucose is a six-carbon sugar. Albumin is a protein with 607 amino acids. The average molecular weight of a single amino acid is 135 g/mole. There is no reason to run these solutes at the 20 MWCO because : d. glucose and albumin are both too large to pass. 50 MWCO : Na+Cl- equilibrium at 10 min (9.00nM) (18.00mM) 100 (9.00mM) Urea 16 min (9.00mM)
4/ The rate of diffusion for urea : B. is slower than that sodium because urea is larger molecule