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#secondary metabolites

21 public questions tagged with this topic.

Immobilized plant cell cultures enhance secondary metabolites because they:

Enhanced secondary product formation in encapsulated systems results from combination of stress alleviation and differentiation cues. Free suspensions expose fragile vacuolated cells to hydrodynamic forces that rupture tonoplast and trigger oxidative burst through phenylalanine ammonia lyase activation leading to browning. Entrapment in alginate or pectate gel dampens shear, maintains high local cell density that mimics tissue context, facilitates accumulation of signaling molecules such as oligosaccharides, and reduces growth rate, redirecting carbon flux from cell division to phenylpropanoid

Ref: Brodelius FEBS Lett 1979 immobilization metabolites; Tanaka J Ferment Bioeng 1993 shear protection; NCBI PMC3425142; Shuler Bioprocess Eng.

Increase in secondary metabolites in cell culture is commonly achieved by:

Increasing secondary metabolite accumulation in plant cell cultures is commonly achieved by supplementation with elicitors after achieving adequate biomass. Secondary metabolism is resource costly competing with primary growth for carbon nitrogen and energy, regulated by growth defense trade off controlled by TOR kinase promoting growth versus SnRK1 promoting defense. Under normal culture high auxin low stress conditions flux stays in primary metabolism. Elicitor addition artificially activates jasmonate and salicylate mediated defense transcriptome inducing genes encoding rate limiting enzyme

Ref: Mishra & Ranjan 2008 secondary metabolite; PubMed elicitor methyl jasmonate.

Elicitors enhance secondary metabolite production by:

Elicitors boost secondary metabolite production by mimicking biotic attack triggering plant innate defense signaling and activation of defence related enzymes. Biotic elicitors include fungal cell wall fragments chitin chitosan glucans yeast extract bacterial flagellin; abiotic include jasmonic acid methyl jasmonate salicylic acid heavy metals copper cadmium UV-C ozone. Perception by pattern recognition receptors triggers calcium influx cyclic nucleotide gated channels, production of reactive oxygen species via NADPH oxidase RBOH, activation of mitogen activated protein kinase cascades MPK3 MP

Ref: Ramachandra & Ravishankar Plant Cell Rep 2002 elicitors; Nature Plants secondary metabolism.

Solid state fermentation is best suited for production of:

Solid state fermentation employs microbial growth on moist solid particles in near absence of free water, with water activity maintained around 0.6 to 0.9 and moisture bound within matrix pores. This environment mimics natural habitats of filamentous fungi where aerial mycelial penetration and sporulation are favored. Porous lignocellulosic substrates like wheat bran, rice husk, sugarcane bagasse, and soybean meal provide carbon, nitrogen and physical anchorage. Low water availability reduces bacterial contamination risk, limits catabolite repression, lowers effluent generation and enhances ox

Ref: Pandey et al. Biotechnology Advances 2000 Solid state fermentation review; Stanbury et al. Principles of Fermentation Technology Ch 7.

Secondary metabolites are typically produced:

Pick B: In specialized tissues. Thinking through PSS- Sec G- Sec metabolites step by step rules out the lookalikes and leaves In specialized tissues. Skip these: A) In all cells equally; C) Only in roots; D) Only in leaves. For hormones and genes, match the molecule or gene to its real role, not a neighboring pathway.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

Plants synthesize secondary metabolites mainly for:

The right choice is B: Defense and interaction. In PSS- Sec G- Sec metabolites, that matches how the process or concept actually works — the other choices mix up related ideas or use the wrong mechanism. Skip these: A) Primary metabolism; C) Energy storage; D) Cell division. A quick check: if an option needs energy, pumps, or the opposite direction of movement, ask whether that really applies.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

Which secondary metabolite class is nitrogen-free?

Go with C — Terpenoids. Under PSS- Sec G- Sec metabolites, this is the standard explanation you’d use in class: it names the real driver or definition, while the rest are nearby but wrong. Not these: A) Alkaloids; B) Glucosinolates; D) All are nitrogenous. When two options sound similar, choose the one that matches the textbook definition most tightly.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

Phenylpropanoid pathway originates from amino acid:

B fits best: Phenylalanine. Keep the PSS- Sec G- Sec metabolites basics straight and Phenylalanine stands out as the precise answer. Avoid: A) Tryptophan; C) Tyrosine; D) Methionine. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

Terpene synthases primarily catalyze:

Correct option is B, Carbon skeleton diversification. In PSS- Sec G- Sec metabolites problems like this, the accurate statement is Carbon skeleton diversification; the others are common mix-ups. Not these: A) C5 unit formation; C) Oxidation reactions; D) Glycosylation. Tissue transport questions usually turn on xylem vs phloem, living vs dead cells, or source vs sink.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

Lignin belongs to which class of secondary metabolites?

C fits best: Phenolics. Keep the PSS- Sec G- Sec metabolites basics straight and Phenolics stands out as the precise answer. Avoid: A) Alkaloids; B) Terpenoids; D) Glucosinolates. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.