Wednesday, 24 June 2015

Cell Cultivations

Cell Cultivations

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Which of the following is the necessary step for cultivating the microorganisms?

a. Preparing a culture medium for the growth of microorganisms
b. Sterilizing in order to eliminate all living microorganisms in vessel
c. Inoculating the microorganisms in the prepared medium
d. All of the above

Suspension cultures consist of cells and cell aggregates, growing dispersed in___________.

a. liquid medium
b. solid nutrient medium
c. solid or liquid medium
d. none of these

Thiobacillus thiooxidans has an optimum pH of ___________.

a. 2.0-3.5        
b. 0.5-6.0
c. 6.5-7.5
d. 9.0-9.5

Balanced growth is defined as ___________.

a. cultures undergoing balanced growth while maintaining a constant chemical composition
b. balancing the growth while controlling the pH
c. balancing the growth while controlling the temperature
d. balancing the growth while changing the nutrient composition

The archaebacterium Halobacterium, an extreme halophile, and Sulfolobus, a thermoacidophile, can be cultured in the presence of antibiotics such as streptomycin and chloramphenicol because ___________.

a. they contain ether-linked isoprenoids in their plasma membrane
b. they lack murein in their cell wall
c. they contain 80S, as opposed to 70S, ribosomes
d. all of the above

For most bacteria, the optimum pH for growth lies between ___________.

a. 6.5-7.5        
b. 3.5-4.5
c. 4.5-5.5        
d. 5.5-6.5

Which of the following is an abiotic elicitors?

a. UV irradiation
b. Osmotic shock
c. Heavy metal ions
d. All of these

The isolation of the gonorrhoea - causing organisms, Neisseria gonorrhoeae,from a clinical specimen is facilitated by the use of media containing

a. cellulose
b. certain antibiotics
c. succinate
d. none of these

Semi-solid media, prepared with agar at concentrations of 0.5% or less are useful for the cultivation of ___________.

a. Microaerophillic bacteria
b. Lactobacilli
c. E.coli
d. all of these

The cell mass can be measured optically by determining the amount of light scattered by a suspension of cells. The measurements are usually at a wavelength of ___________.

a. 300-400nm 
b. 400-500nm
c. 500-600nm 
d. 600-700nm

Stringent anaerobes can be grown in a media by taking special measure as ___________.

a. boiling the media for several minutes
b. addition of cysteine
c. passing through oxygen-free nitrogen
d. any of these

Radical shifts in pH can be prevented by incorporating ___________.

a. a buffer
b. an oxidizing agent
c. a reducing agent
d. any of these

The protoplast can be used to ___________.

a. modify genetic information
b. create plant hybrid
c. study plant viral infections
d. all of these

Which of the following is incorrect?

a. Mammalian cells are larger and more complex than microorganisms
b. Their growth rate is very fast compared to microorganisms
c. Mammalian cells are fragile
d. Most animal cells only grow when attached to surface

The size of a single plant cell is usually within the range of ___________.

a. 10-20μm in diameter and 25-100μm long
b. 20-40μm in diameter and 100-200μm long
c. 40-60μm in diameter and 200-300μm long
d. 60-80μm in diameter and 300-400μm long

Which of the following is incorrect?

a. Plant cells are larger than the bacterial or fungus cells
b. Plant cells tend to grow in clumps
c. Plant cells are less sensitive to shear than microbial cells
d. Plant cells are more genetically unstable than microbial cells

Anchorage -dependent cells require ___________.

a. wettable surface for growth
b. dry surface for growth
c. either (a) or (b)
d. nothing to do with the surface

Which of the following is not an indirect method for the measurement of cell mass?

a. Nutrient composition
b. Cell dry weight
c. Viscosity
d. Heat evolution

Callus cultures are amorphous cell aggregates arising from the unorganized growth of explants on an ___________.

a. liquid medium
b. solid nutrient medium
c. aseptic solid nutrient medium
d. solid or liquid medium
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