Kingdom Monera

Includes prokaryotic organisms like bacteria, characterized by no true nucleus, found everywhere, including extreme habitats; examples include Nostoc and Anabaena.

Archaebacteria

Prokaryotes living in harsh habitats like salty areas (halophiles), hot springs (thermoacidophiles), and marshy areas (methanogens).

Methanogens

Archaebacteria producing methane, found in anaerobic environments like the gut of ruminants (e.g., cows, buffaloes), contributing to biogas production.

Eubacteria

True bacteria with rigid peptidoglycan cell walls, often motile with flagella; include photosynthetic cyanobacteria like Nostoc and Anabaena.

Peptidoglycan

A polysaccharide and amino acid polymer forming the rigid cell wall of eubacteria, absent in archaebacteria.

Cyanobacteria

Photosynthetic bacteria (blue-green algae) with chlorophyll a, often forming blooms in polluted water; some fix nitrogen in heterocysts, e.g., Nostoc, Anabaena.

Heterocysts

Specialized cells in cyanobacteria like Nostoc and Anabaena for nitrogen fixation, protecting the nitrogenase enzyme from oxygen.

Mycoplasma

Smallest living cells, lacking a cell wall, resistant to antibiotics targeting cell walls, often pathogenic, e.g., Mycoplasma pneumoniae (causes pneumonia).

Chemosynthetic Autotrophic Bacteria

Bacteria that oxidize inorganic substances (e.g., nitrates, nitrites, ammonia) for energy, aiding nutrient recycling, e.g., sulfur bacteria.

Kingdom Protista

Unicellular eukaryotes with a defined nucleus and organelles, primarily aquatic; includes Chrysophytes, Dinoflagellates, Euglenoids, Slime moulds, and Protozoans.

Chrysophytes

Protists like diatoms and golden algae (desmids), mostly photosynthetic, with silica-embedded cell walls; diatoms form diatomaceous earth, used in polishing.

Dinoflagellates

Mostly marine, photosynthetic protists with two flagella and cellulose plates; some cause red tides, e.g., Gonyaulax.

Red Tides

Phenomenon caused by rapid multiplication of dinoflagellates like Gonyaulax, making the sea appear red and releasing toxins that kill marine animals.

Euglenoids

Freshwater protists with a flexible pellicle, mixotrophic (photosynthetic or heterotrophic); pigments similar to higher plants, e.g., Euglena.

Pellicle

A protein-rich layer in euglenoids like Euglena, providing flexibility instead of a rigid cell wall.

Slime Moulds

Saprophytic protists forming a multinucleate plasmodium; produce resistant spores in fruiting bodies.

Protozoans

Heterotrophic protists, living as predators or parasites; include amoeboid (Amoeba), flagellated (Trypanosoma), ciliated (Paramoecium), and sporozoans (Plasmodium).

Amoeboid Protozoans

Protozoans moving and feeding via pseudopodia; live in fresh water, sea, or soil; some are parasitic, e.g., Entamoeba (causes amoebiasis).

Flagellated Protozoans

Protozoans with flagella, either free-living or parasitic; cause diseases like sleeping sickness, e.g., Trypanosoma.

Ciliated Protozoans

Aquatic protozoans with cilia for movement and feeding via a gullet, e.g., Paramoecium.

Sporozoans

Protozoans with an infectious spore-like stage, often parasitic; cause diseases like malaria, e.g., Plasmodium.

Kingdom Fungi

Heterotrophic eukaryotes with chitin cell walls, mostly multicellular; saprophytic or parasitic; include Penicillium, Agaricus, Puccinia.

Mycelium

A network of thread-like hyphae forming the fungal body, as in Mucor, Aspergillus, Agaricus.

Hyphae

Thread-like structures in fungi; may be coenocytic (e.g., Mucor) or septate (e.g., Aspergillus, Agaricus).

Coenocytic Hyphae

Continuous, multinucleate hyphae without septa, found in phycomycetes like Mucor and Rhizopus.

Septate Hyphae

Hyphae divided by cross-walls (septa), found in ascomycetes (Aspergillus) and basidiomycetes (Agaricus).

Phycomycetes

Aquatic or damp-habitat fungi with coenocytic mycelium; reproduce via zoospores or aplanospores; e.g., Mucor, Rhizopus, Albugo.

Zoospores

Motile spores with flagella, produced endogenously in sporangia by phycomycetes like Mucor and Rhizopus.

Aplanospores

Non-motile spores produced endogenously in sporangia by phycomycetes like Mucor and Rhizopus.

Ascomycetes

Sac fungi, mostly multicellular, producing ascospores in asci; e.g., Saccharomyces (yeast), Penicillium, Aspergillus, Neurospora.

Ascospores

Sexual spores produced endogenously in asci within ascocarps, found in ascomycetes like Aspergillus, Penicillium.

Conidia

Asexual spores produced exogenously on conidiophores in ascomycetes (Aspergillus, Penicillium) and deuteromycetes (Alternaria).

Basidiomycetes

Club fungi producing basidiospores on basidia in basidiocarps; e.g., Agaricus (mushroom), Ustilago (smut), Puccinia (rust).

Basidiospores

Sexual spores produced exogenously on basidia in basidiomycetes like Agaricus, Ustilago.

Deuteromycetes

Imperfect fungi with only asexual reproduction via conidia; e.g., Alternaria, Colletotrichum, Trichoderma.

Plasmogamy

Fusion of protoplasms between two gametes or hyphae in fungi, the first step in sexual reproduction, seen in Mucor, Agaricus.

Karyogamy

Fusion of two nuclei during fungal sexual reproduction, following plasmogamy, occurring in Aspergillus, Agaricus.

Dikaryophase

A phase in ascomycetes (Aspergillus) and basidiomycetes (Agaricus) where cells contain two nuclei (n+n) before karyogamy.

Viruses

Non-cellular, obligate parasites with a protein capsid and DNA or RNA; cause diseases like tobacco mosaic, e.g., TMV, Bacteriophage.

Capsid

Protein coat of viruses made of capsomeres, protecting the nucleic acid; found in TMV, Bacteriophage.

Bacteriophage

Viruses infecting bacteria, usually with double-stranded DNA, e.g., Bacteriophage mentioned in the context of viral structure.

Viroids

Free, low molecular weight RNA without a protein coat, causing plant diseases like potato spindle tuber disease.

Prions

Infectious protein agents causing neurological diseases like Creutzfeldt-Jakob disease (CJD) in humans and mad cow disease (BSE) in cattle.

Lichens

Symbiotic associations between a fungus (mycobiont) and an alga/cyanobacterium (phycobiont), acting as pollution indicators.

Phycobiont

The autotrophic algal or cyanobacterial partner in lichens, preparing food for the fungal partner.

Mycobiont

The heterotrophic fungal partner in lichens, providing shelter and absorbing nutrients for the phycobiont.