NCERT Quick Recap Points Demo

This NCERT Quick Recap Points are prepared on basis of NCERT Book.

 

  • Aristotle​​ was the earliest scientist to attempt a more scientific basis for classification. He used simple morphological characters to classify plants into​​ trees, shrubs and herbs.​​ 

  • Linnaeus proposed Two Kingdom system of classification. He placed all the organisms into kingdoms Plantae and Animalia.​​ 

  • The​​ Five Kingdom​​ classification system proposed by​​ R.H​​ Whittaker(1969)​​ is based on criterias like​​ cell structure, body organization, mode of nutrition, reproduction and phylogenetic relationships.​​ 

  • He proposed five kingdoms​​ Monera, Protista, Fungi, Plantae and Animalia.​​ 

  • Monera​​ includes all prokaryotes.

  • Bacteria​​ are sole members of Kingdom Monera.

  • Bacteria​​ structure is very simple​​ but they are very​​ complex in behaviour​​ 

  • Protista​​ includes unicellular eukaryotes​​ 

  • Fungi​​ includes organism with multicellular, loose tissue organisation and chitinuous cell wall.​​ 

  • Monera later on divided into two kingdoms​​ Archaebacteria and Eubacteria.​​ 

  • The​​ three-domain system has also been proposed that divides monera into two domains and placed all eukaryotes in single domain.​​ 

  • Archaebacteria live in extreme conditions such as salty area (halophiles) hot springs (thermoacidophiles) and marshy area (methanogens).​​ 

  • Methanogens are present in the gut of several ruminant animals such as cows and buffaloes and they are​​ responsible for the production of methane from the dung of these animals.

  • Cyanobacteria have​​ chlorophyll A​​ similar to green plants​​ 

  • In Nostoc, the​​ site of nitrogen fixation is​​ heterocysts.

  • Chemoautotrophic bacteria oxidise various inorganic substance such as​​ nitrate, nitrites​​ and​​ ammonia​​ and used the release energy for their​​ ATP production.​​ 

  • Cholera, tetanus, and citrus canker​​ are well known diseases caused by different​​ bacteria.​​ 

  • Bacteria asexually reproduce mainly by fission. Sexual reproduction includes primitive type of DNA transfer​​ 

  • Mycoplasma​​ are organisms that completely lack a cell wall. They are smallest living cells known and can survive​​ without oxygen.

  • All​​ single celled eukaryotes​​ are placed under Protista.​​ 

  • Chrysophytes, euglenoids, slime moulds and protozoans belong to the kingdom​​ Protista.​​ 

  • Chrysophytes​​ include diatoms and desmids.​​ 

  • In diatoms, the cell wall forms two thin overlapping​​ shells, that fit together as in a soap box.​​ 

  • Diatoms left behind large amount of​​ cell wall​​ (impregnated with silica) deposits in their habitat; this accumulation over billions of years is referred to as​​ 'diatomaceous earth'.​​ 

  • Diatoms are the chief​​ 'producers' in the oceans.​​ 

  • Dinoflagellates are​​ mostly marine​​ and photosynthetic. Red dinoflagellate (Gonyaulax) makes the sea appear red.​​ 

  • Euglenoids are fresh water organisms found in stagnant water. Instead of cell wall, they have a protein rich layer called​​ pellicle​​ which makes their body flexible. They are photosynthetic but in absence of sunlight behave as heterotroph.

  • Slime moulds are saprophytic​​ protists.​​ 

  • Under suitable conditions, slime moulds form an aggregation called​​ plasmodium​​ which may grow and spread over several feet.

  • Protozoans are believed to be​​ primitive relative of animals.​​ 

  • There are four major groups of protozoans like amoeboid, flagellated, ciliated and sporozoans.​​ 

  • Sleeping sickness is caused by a flagellated protozoan called Trypanosome.

  • Fungi that depend on living plants and animals are called​​ parasites.​​ 

  • Fungal body is made up of thread like​​ hyphae (coenocytic or septate/uninucleate).​​ 

  • Fungi can live as symbionts- in association with algae as lichens and with roots of higher plants​​ as mycorrhiza.​​ 

  • Fungi growing on cattle dung are called coprophilous.​​ 

  • Fungi asexually reproduce through​​ zoospores, conidia, sporangiospores, oidia and chiamydospores.​​ 

  • Fungi produce sexual spores or meiospores like ascospores and basidiospores.​​ 

  • Mycelium​​ is aseptate and coenocytic in phycomycetes.​​ 

  • Fusion of protoplasm between two motile or non-motile gametes is called plasmogamy.​​ 

  • In phycomycetes. asexual reproduction takes place by zoospores and aplanospores.​​ 

  • Albugo (parasite on mustard) and Mucor belong to the phycomycetes group of fungi.​​ 

  • Ascomycetes are commonly known as​​ sac-fungi.​​ 

  • Asexual spores, conidia are produced in ascomycetes.​​ 

  • Ascospores are​​ endogenously produced.

  • Neurospora, yeast, morels, truffles and Claviceps belong to the class ascomycetes.​​ 

  • In basidiomycetes, asexual spores are generally not found, but vegetative reproduction by fragmentation is common.​​ 

  • In basidiomycetes, sex organs are absent but plasmogamy is brought about by fusion of two vegetative or​​ somatic cells of different strains or genotypes.​​ 

  • The basidiospores are exogenously produced on the basidium.​​ 

  • Puccinia, Agaricus and Ustilago belongs to basidiomycetes.​​ 

  • Deuteromycetes are commonly known as imperfect fungi because only the asexual or vegetative phases of these fungi​​ are known.​​ 

  • The deuteromycetes reproduce by asexual spores known as​​ conidia.​​ 

  • Alternaria, Colletotrichum and Trichoderma belongs to class deuteromycetes.​​ 

  • Bladderwort and Venus fly trap are examples of insectivorous plants and Cuscuta is a parasite.​​ 

  • The viruses are non-cellular and are​​ characterized by having an inert crystalline structure​​ outside the living cell.​​ 

  • The name virus that means venom or poisonous fluid was given by Pasteur.​​ W.M.Stanley​​ showed that viruses could be crystallized and crystals consist largely of protein.​​ 

  • Viruses are obligate parasites.​​ 

  • In general, viruses that infect plants have​​ single stranded RNA like TMV​​ and viruses that infect​​ animals have either single or double stranded RNA or double stranded DNA.​​ 

  • Bacterial viruses or​​ bactriophages are usually double stranded DNA viruses.​​ 

  • Viroids are smaller than viruses, contains only RNA and cause potato spindle tuber disease.

  • Prions are abnormally folded proteins, smaller than viruses.​​ 

  • In lichens, the​​ algal​​ component is known as​​ phycobiont​​ and​​ fungal​​ component as​​ mycobiont.​​ 

  • In five kingdom classification of Whittaker there is no mention of​​ lichens and viruses, viroids and prions.

 

 

 

 

  • Anaima​​ : Animals without​​ RBCs.​​ 

  • Enaima​​ : Animals having​​ RBCs.​​ 

  • Phylogenetic​​ : Evolutionary inter-relationship.​​ 

  • Heterocysts​​ : Specialised cells in cyanobacteria for​​ N2​​ fixation.​​ 

  • Saprophytes​​ : Are organisms which obtain (absorb) their food from dead and decaying substances.​​ 

  • Parasites​​ : Depend on living plants and animals for nutrition.​​ 

  • Plasmogamy​​ : Fusion of protoplasm between two motile or non-motile gametes, called plasmogamy.​​ 

  • Mycelium​​ : The network of hyphae.​​ 

  • Phycobiont​​ : Algal component of lichens.

  • Mycobiont​​ : Fungal component of lichens.

 

 

 

 

 

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