Plant cell culture characteristics: Which of the following statements is incorrect regarding plant cells in culture compared with bacterial or fungal cells?
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APlant cells are larger than bacterial or fungal cells
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BPlant cells tend to grow in clumps (aggregates) in suspension
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CPlant cells are less sensitive to shear than microbial cells
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DPlant cells are more genetically unstable than microbial cells (somaclonal variation can occur)
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EPlant cells often require higher auxin/cytokinin control for morphogenesis
Answer
Correct Answer: Plant cells are less sensitive to shear than microbial cells
Explanation
Introduction / Context:Plant cell and tissue cultures are key to micropropagation, metabolite production, and genetic engineering. Their physical and physiological characteristics differ markedly from microbial cultures, impacting reactor design, agitation, and process yields.
Given Data / Assumptions:
- Plant cells are generally larger and vacuolated compared with microbes.
- Suspension cultures frequently form aggregates (clumps), altering mass transfer.
- Somaclonal variation (genetic instability) may arise during plant tissue culture.
Concept / Approach:Due to large size, fragile cell walls, and vacuolation, plant cells are typically more shear sensitive than bacteria or fungi. They require gentler mixing (low tip speeds) and specialized impellers. Clumping is common, affecting oxygen/nutrient gradients and complicating homogeneous growth. Hormone balance (auxins/cytokinins) controls morphogenesis. Therefore, any statement claiming plant cells are “less shear sensitive” than microbes is incorrect.
Step-by-Step Solution:List known traits: large size, aggregation, hormone dependence.Contrast shear tolerance: microbes > plant cells for typical agitation regimes.Identify the incorrect option as the one stating “less sensitive to shear.”
Verification / Alternative check:Bioreactor guidelines recommend gentle agitation, bubble-free aeration (membrane sparging), and shear protectants (e.g., Pluronic F-68) for plant cells, confirming higher shear sensitivity.
Why Other Options Are Wrong:
- Size larger: true.
- Clumps: true and widely observed.
- Genetic instability: true—somaclonal variation is a known issue.
- Hormone control: true—auxin/cytokinin ratios drive callus vs organogenesis.
Common Pitfalls:Applying microbial agitation/aeration parameters to plant cultures; ignoring aggregate size control.
Final Answer:Plant cells are less sensitive to shear than microbial cells.