1. The viscosity of liquid was classified as both dilatant and rheopectic, which means that the viscosity
A.increased with stirring speed but decreased with mixing time
B.increased with stirring speed and increased with mixing time
C.decreased with stirring speed but increased with mixing time
D.decreased with stirring speed and decreased with mixing time
2. Which of the following describes the detrimental effect of bubbles on animal cells?
A.Cells trapped on the surface of bubbles can be damaged when the bubbles explode, releasing their pressure and surface energies
B.Cells trapped in the moving foam can be dragged apart by the bubbles
C.Both (a) and (b)
D.Bubbles can explode in the liquid medium causing the release of ultraviolet radiation
3. A fluid in which the viscosity decreases with increasing stirrer speed and mixing time, can be represented as
A.newtonian fluid
B.pseudoplastic, thixotropic fluid
C.dilatant, rheopectic fluid
D.dilatant, pseudoplastic fluid
4. Filamentous fungal cells are more shear sensitive than bacterial cells because of
A.the presence of citin in cell walls of filamentous fungi
B.larger in size than bacterial cells and therefore are more susceptible to shear forces
C.fungal cells are much larger than bacterial cells
D.all of the above
5. The viscosity of water at STP is approximately
A.0.005 kg.m-1.s-1
B.0.001 kg.m-1.s-1
C.0.003 kg.m-2.s-1
D.0.1 g.cm-1.s-1
6. Bubble free aeration systems requires
A.silicone tubing or gas permeable membranes to facilitate gas transfer
B.carbon dioxide instead of air to supply oxygen
C.silicone tubing or gas permeable membranes to remove carbon dioxide by oxygen in the form of hydrogen peroxide
D.filled headspace of the reactor with carbon dioxide
7. Non-linear relationship between shear stress and shear rate exists in
A.newtonian fluids
B.non-newtonian fluids
C.both (a) and (b)
D.none of these
Page 1 of 7