12 public questions tagged with this topic.
Yeast reproduces asexually by budding, where a new ll forms as an outgrowth of the parent ll. This follows from NCERT principle where relation explains outcome clearly for students.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Biology - Botany portion covering relevant concept, Topic: Plant structure, physiology and applications.
Maltose, a reducing sugar with two glucose units, is fermented by yeast to produce ethanol and CO₂.
Ref: NCERT Class 12 Chemistry > Chapter 14: Biomolecules > Topic: Carbohydrates - Disaccharides and Glycosidic Linkage
Coffee bean processing requires removal of pectin-rich mucilage layer surrounding parchment after pulping, a task accomplished through controlled microbial fermentation lasting 12 to 36 hours. Erwinia dissolvens, now taxonomically revised as Pantoea agglomerans, along with other enterobacteria such as Erwinia herbicola, initiates mucilage depolymerization by secreting extracellular polygalacturonase, pectin lyase and pectin methylesterase that hydrolyze alpha-1,4-linked D-galacturonic acid residues and methyl esters in pectic polysaccharides. This enzymatic breakdown drastically reduces viscosity, liberates simple sugars like glucose and fructose subsequently utilized by yeasts Saccharomyces and lactic acid bacteria producing organic acids that modestly lower pH from 6.5 to 4.2 facilitating washing and preventing germination. Aroma precursors generated during this phase influence final cup quality, while prolonged over-fermentation risks formation of butyric and propionic off-flavors from Clostridia. Wet-processed arabica relies heavily on bacterial pectinolysis for uniform bean drying, representing classic example of natural plant waste bioconversion for beverage quality improvement. Ecological succession later includes Bacillus, Pseudomonas putida and yeast Debaryomyces providing additional pectinolytic, cellulolytic enzymes that further clean bean surface, reduce water usage during washing and contribute to disease suppression in nursery seedlings.
Ref: Avallone et al. Applied Microbiology Biotechnology 2002 Coffee fermentation; Haile & Kang Int J Food Microbiol 2019.
Escherichia coli is used to produce recombinant human insulin through genetic engineering.
Ref: NCERT Class 12 Biology Chapter 10: Biotechnology and its Applications Medical Applications - Genetically Engineered Insulin
Saccharomyces cerevisiae (yeast) is used in the fermentation of sugar to produce ethanol.
Ref: NCERT Class 12 Biology Chapter 8: Microbes in Human Welfare Microbes in Biogas Production - Methanogens
Yeast produces carbon dioxide during fermentation, which causes the dough to rise.
Ref: NCERT Class 12 Biology Chapter 8: Microbes in Human Welfare Microbes in Industrial Products - Organic Acids Enzymes Bioactive Molecules
Yeast is a unicellular fungus used in preparing bread and beer and belongs to Ascomycetes. Budding is one of the vegetative methods of reproduction described for fungi.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Phycomycetes Ascomycetes Basidiomycetes
Yeast is a unicellular fungus used in the preparation of bread and beer. Most other fungi are filamentous and possess bodies made of hyphae.
Ref: NCERT Class 11 Biology Chapter 2: Biological Classification Fungi - Phycomycetes Ascomycetes Basidiomycetes
Saccharomyces cerevisiae, commonly known as baker's or brewer's yeast, is a unicellular ascomycete where asexual reproduction predominantly involves budding, an asymmetric mitotic process producing genetically identical daughter cells. A small bud emerges on mother cell surface after S-phase, nucleus divides by mitosis, one nucleus migrates into growing bud along with cytoplasm and organelles, cytokinesis forms septum leaving chitinous bud scar. Mother continues producing multiple buds sequentially, daughter enlarges to parent size before separation. This rapid proliferation dominates sugar-rich environments like dough fermentation, differing from fragmentation, exogenous conidia formation or transverse binary fission.
Ref: NCERT Class 11 Biology Chapter 2: Fungi; Lodish Molecular Cell Biology 8th ed., Yeast Cell Cycle
Telomeric position effect in budding yeast involves Sir complex spreading from chromosome ends inward silencing subtelomeric genes. Rap1 protein binds TG1-3 telomere repeats recruiting Sir4 which interacts with Sir2 histone deacetylase. Sir2 deacetylates adjacent nucleosomal H4K16 and H3K9, generating high-affinity binding site for Sir3 chromodomain interacting with deacetylated tails, recruiting additional Sir2-Sir4 complexes iteratively propagating heterochromatin several kilobases. This histone deacetylation dependent polymerization requires continuous Sir2 NAD-dependent activity, blocked by boundary elements or acetyltransferases. Disruption of deacetylation restores acetylation evicting Sir proteins activating normally silent loci, illustrating requirement for histone deacetylation in spreading and maintenance of telomeric heterochromatin inheritance.
Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 8: Telomeric Silencing Spread via Histone Deacetylation
Saccharomyces cerevisiae GAL regulon glucose repression is mediated predominately by C2H2 zinc finger transcription factor Mig1, functional homolog of mammalian EGR proteins. Under high glucose, hexokinase Hxk2 signals inactivation of Snf1 kinase, permitting Mig1 nuclear localization and binding to GC-rich consensus CCCCG motifs in GAL1, GAL4, GAL3 promoters. Mig1 does not mask Gal4 activation domain like Gal80, but actively recruits corepressors to block transcription of structural genes and regulatory activators. Deletion of MIG1 partially relieves glucose repression, allowing galactose-independent GAL expression, demonstrating central role in carbon catabolite repression hierarchy overriding galactose induction signals prioritizing glucose utilization efficiency.
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 7: Yeast GAL Regulation – Mig1 Glucose Repression
Hog1, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)
