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#plant cells

28 public questions tagged with this topic.

Plant tissue culture 3

Immobilization of plant cells helps in:

Plant cell suspension bioreactors generate hydrodynamic stresses from Rushton turbine agitation and aeration bubbles bursting at surface. Large vacuolated cells with thin primary wall shear more readily than microbial cells, leaking phenolics that cause browning and viability loss. Immobilization in calcium alginate beads of 2 to 4 mm diameter forms porous hydrogel matrix where cells entrap as microcolonies, shielding them from direct impeller impact and reducing turbulent eddies. Diffusion of nutrients and oxygen through beads sustains metabolism while preventing cell washout in perfusion mod

Ref: Brodelius Tibtech 1985 immobilized cells; Fowler Crit Rev Biotech 1986 shear; NCBI PMC3566382 alginate encapsulation; Yeoman Plant Cell Culture bioreactor.

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Plant tissue culture 1

Totipotency in plant cells refers to the ability to:

Totipotency describes inherent potential of differentiated plant cell retaining complete genome and regulatory capability to dedifferentiate, proliferate, and regenerate entire organism given appropriate hormonal and nutritional cues. Concept stems from Haberlandt 1902 hypothesis that every plant cell nucleus holds total genetic information necessary for whole plant development. Mature parenchyma, leaf mesophyll, or root cortical cells can be induced by auxin-cytokinin balance to re-enter cell cycle, form callus, then undergo organogenesis or somatic embryogenesis producing shoot, root, and wh

Ref: Haberlandt 1902 totipotency; Thorpe TA. Plant tissue culture concepts; NCBI – Plant cell totipotency review

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Basics of Cell Biology

Which of the following best describes a plastid?

Plastids comprise diverse double-membrane organelles in plant and algal lineages originating from primary endosymbiosis of cyanobacterium engulfed by eukaryote over billion years ago, retaining circular plastid genome encoding photosystem components and ribosomal RNAs and ability to divide by binary fission via FtsZ ring. Differentiation depends on tissue and environmental cues: chloroplasts in mesophyll contain thylakoid stacks grana where photosystem II, cytochrome b6f, photosystem I perform light reactions generating proton gradient for ATP synthase and NADPH for Calvin cycle fixing CO2 via

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 14: Plastids, Chloroplasts, and Photosynthesis.

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Membrane Transportation

Which ATPase is crucial for acidifying vacuoles in plant cells?

Plant central vacuole occupies major cellular volume functioning in turgor generation, storage of ions, sugars, pigments, anthocyanins and toxic metabolites, pH regulation and degradation analogous to animal lysosomes. Luminal pH typically 5 to 5.5 maintained acidic relative to cytosol 7.5 to support proton coupled antiport of calcium via CAX, sodium via NHX, sugars and sequestration of xenobiotics. Acidification achieved by two proton pumps coexisting in tonoplast: V-type proton ATPase and proton pyrophosphatase using pyrophosphate. Dominant contributor is V-ATPase, multisubunit rotary machin

Ref: Sze et al., Trends Plant Sci, Plant Vacuolar V-ATPase Acidification of Vacuoles and Tonoplast.

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Membrane Transportation

Which type of solution would cause plasmolysis in plant cells?

Plant cell physiology depends heavily on water status because central vacuole can occupy 90 percent volume generating hydrostatic turgor pressure essential for cell expansion and mechanical support. Turgor results from water entry driven by intracellular solute accumulation, pressing protoplast against rigid cellulose cell wall. Membrane surrounding protoplast semipermeable allows water but restricts many solutes. If external soil solution or surrounding medium becomes hypertonic containing higher total effective concentration of non-penetrating solutes such as sodium chloride, mannitol or suc

Ref: Taiz & Zeiger, Plant Physiology, Chapter 3: Plasmolysis and Hypertonic Effects in Plant Cells.

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Cell Organelles

Which plastid stores lipids?

Plastid diversity reflects differentiation of proplastids in meristems according to tissue identity and developmental signals regulated by light, hormones and transcription factors. Elaioplasts are specialized non-photosynthetic leucoplasts lacking chlorophyll that function in lipid storage and metabolism crucial for reproduction. They are abundant in oil seeds like Brassica, citrus exocarp oil glands, and anther tapetum where lipid reserves for pollen coat tryphine formation and pollinator attraction are needed. Ultrastructurally they contain numerous electron-dense plastoglobuli and oil drop

Ref: Wise & Hoober, The Structure and Function of Plastids, Chapter 9: Classification of Leucoplasts and Elaioplasts.

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Cell Organelles

In plants, the Golgi apparatus plays a role in:

In animal cells Golgi modifies proteins, but plant cells possess additional requirement to produce noncellulosic cell wall polysaccharides that constitute matrix embedding cellulose microfibrils. Golgi stacks, often four hundred per cell moving along actin tracks, synthesize pectins homogalacturonan methylesterified in cis medial then de-esterified and calcium crosslinked in trans and at wall, rhamnogalacturonan I II highly branched, and hemicelluloses xyloglucan backbone synthesized by CSLC glucan synthases, xylan, arabinan, galactan sidechains added by glycosyltransferases GT47, GT8 families

Ref: Richmond Annu Rev Plant Biol; plant Golgi pectin hemicellulose synthases cell plate wall.

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