6. When dissolved oxygen is lower than the critical concentration, viable cell concentration declines because of

A. incomplete glutamine oxidation
B. increase in specific lactate production from glucose
C. both (a) and (b)
D. accumulation of ammonia

7. According to Eagle, the growth of L-strain and Hela-strain cultures require to have the mandatory presence of

A. 6 amino acids
B. 8 amino acids
C. 10 amino acids
D. 12 amino acids

8. Excess CO₂ suppress cell growth and productivity by

A. inhibiting respiration
B. altering intracellular pH by diffusing across the cell membrane
C. both (a) and (b)
D. altering pH of the medium

9. Which of the following is incorrect?

A. Established cell lines (ECL) have short doubling time
B. ECL are invariably aneuploid
C. ECL grow in higher density
D. ECL do not show much evidence of spatial orientation

10. What is the effect of excess accumulation of metabolite products (lactate and ammonium) on cells?

A. They act as growth promoters
B. They act as growth inhibitors
C. Have no effect on cells
D. Lactate helps in the growth while ammonium inhibits the growth