You can find NCERT Solutions Class 11 Biology Chapter 2 on ALLEN, with clear answers to the NCERT textbook questions from Biological Classification.
NCERT Solutions Class 11 Biology Chapter 2 cover the five-kingdom classification, Monera, Protista, Fungi, Plantae, Animalia, viruses, viroids, prions, and lichens.
Whittaker proposed the five-kingdom classification based on important features such as cell structure, body organisation, mode of nutrition, reproduction, and evolutionary relationships.
The chapter covers Phycomycetes, Ascomycetes, Basidiomycetes, and Deuteromycetes, along with their important characteristics and methods of reproduction.
Cyanobacteria are photosynthetic organisms, and some have specialised cells called heterocysts that help in nitrogen fixation.
The solutions explain their important characteristics and show how these biological entities differ from the organisms included in Whittaker's five-kingdom classification.
Yes, NCERT Solutions Class 11 Biology Chapter 2 help students revise important NCERT concepts such as five-kingdom classification, Monera, Protista, Fungi, viruses, viroids, and lichens. They are useful for CBSE board exam revision and provide a strong foundation for NEET preparation.
Yes, NCERT Solutions Class 11 Biology Chapter 2 are based on the topics covered in the NCERT chapter, including the five-kingdom classification, Monera, Protista, Fungi, Plantae, Animalia, viruses, viroids, prions, and lichens. They help students understand important concepts and revise the chapter effectively for CBSE board exams and NEET preparation.
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NCERT Solutions Class 11 Biology Chapter 2 - Biological Classification
NCERT Solutions for Class 11 Biology Chapter 2, Biological Classification, explain how organisms are grouped into different categories based on their similarities, differences, and important characteristics. The chapter introduces R.H. Whittaker's Five Kingdom Classification and explains the major features of Monera, Protista, Fungi, Plantae, and Animalia.
NCERT Solutions for Class 11 Biology Chapter 2 by ALLEN provide clear explanations of the structural, nutritional, and reproductive features of organisms in different kingdoms. Students can learn about Archaebacteria, Eubacteria, Cyanobacteria, Protists, Fungi, Viruses, Viroids, Prions, and Lichens and understand their important characteristics. The solutions also explain the differences between the major groups and help students understand topics such as fungal classification, nitrogen fixation by cyanobacteria, and the characteristics of viruses and viroids.
Class 11 Biology Chapter 2, Biological Classification, explains the basis of classifying organisms into different kingdoms. The chapter covers classification based on cell structure, body organisation, mode of nutrition, reproduction, and other important characteristics.
The key concepts covered in this chapter include:
Kingdom Monera: Study the characteristics of bacteria, including Archaebacteria, Eubacteria, Cyanobacteria, and Mycoplasma, along with their important features.
Kingdom Protista: Understand the characteristics of unicellular eukaryotic organisms, including Chrysophytes, Dinoflagellates, Euglenoids, Slime Moulds, and Protozoans.
Kingdom Fungi: Learn about the structure, nutrition, reproduction, and classification of fungi into Phycomycetes, Ascomycetes, Basidiomycetes, and Deuteromycetes.
Kingdom Plantae: Get an introduction to multicellular, eukaryotic organisms that generally contain chlorophyll and prepare their food through photosynthesis.
Kingdom Animalia: Understand the basic features of multicellular, eukaryotic organisms that are heterotrophic and depend on other organisms for food.
Viruses, Viroids, Prions, and Lichens: Learn about these organisms and biological entities that are not included in Whittaker's five-kingdom classification, along with their important characteristics and significance.
Discuss how classification systems have undergone several changes over a period of time?
Ans. Classification systems have undergone several changes with time. Initially, Linnaeus proposed the Two Kingdom Classification, which included Plantae and Animalia. Later, R.H. Whittaker proposed the Five Kingdom Classification consisting of Monera, Protista, Fungi, Plantae and Animalia. The criteria used for classification included cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships. With advances in molecular biology and our knowledge of evolutionary relationships, classification systems have been further modified.
State two economically important uses of:
(a) heterotrophic bacteria
(b) archaebacteria
Ans.
(a) Heterotrophic bacteria : Many of them have a significant impact on human affairs. They are helpful in making curd from milk, production of antibiotics, fixing nitrogen in legume roots.
(b) Archaebacteria : Methanogens are used for the production of biogas (gobar gas).
Methanogens present in the rumen of cattle help in cellulose digestion and methane production.
What is the nature of cell-wall in diatoms?
Ans. In diatoms the cell walls forms two thin overlapping shells, which fit together as in a soap box. The walls are embedded with silica and thus the walls are indestructible.
Find out what do the terms 'algal bloom' and 'red tides' signify.
Ans.Algal bloom :
The rapid increase or excessive growth of algae in water bodies due to nutrient enrichment, especially nitrates and phosphates, is called an algal bloom.
Red tides :
The rapid multiplication of red dinoflagellates, particularly Gonyaulax, in the sea is called a red tide. It may make the sea appear red and the organisms may release toxins that are harmful to marine life.
How are viroids different from viruses?
Viroids
Viruses
Viroids are smaller infectious agents.
Viruses are comparatively larger infectious entities.
They consist of a small, circular, single-stranded RNA molecule.
They contain DNA or RNA as genetic material.
They do not have a protein coat.
Their genetic material is surrounded by a protein coat called capsid.
Viroids were discovered by T.O. diener.
Viruses were first described by D.J. Invanowsky in tobacco mosaic disease.
6. Describe briefly the four major groups of protozoa.
Ans. All protozoans are heterotrophs and live as predators or parasites. They are be-lieved to be primitive relatives of animals. They are classified into four groups on the basis of locomotory organelles.
(i) Amoeboid protozoans : These organisms live in fresh water, sea water or moist soil. They move and capture their prey by developing pseudopodia (false feet) as in Amoeba. Some of them such as Entamoeba are parasites.
(ii) Flagellated protozoans : The members of this group are either free-living or parasitic. They have flagella for locomotion. The parasitic forms cause diseases such as sleeping sickness e.g., Trypanosoma.
(iii) Ciliated protozoans : These are aquatic, actively moving organisms because of the presence of thousands of cilia. They have a cavity (gullet) that opens to the outside of the cell surface. The coordinated movement of rows of cilia causes the water laden with food to be steered into the gullet e.g., Paramecium.
(iv) Sporozoans : This includes diverse organisms that have an infectious spore like stage in their life cycle. The most notorious is Plasmodium (malarial parasite) which causes malaria which has a staggering effect on human population.
Plants are autotrophic. Can you think of some plants that are partially heterotrophic?
Ans. Some insectivorous plants like Drosera, Nepenthes, are partially heterotrophic plant. These plants are deficient in nitrogen content but are otherwise autotrophic. They, trap various insects to obtain nitrogen from them. Rest, the food i.e., carbohydrate is manufactured by themselves.
What do the terms phycobiont and mycobiont signify?
Ans. In lichen, the algal component is called the phycobiont and the fungal component is called the mycobiont. The phycobiont prepares food by photosynthesis, while the mycobiont provides shelter, water and minerals.
Give a comparative account of the classes of Kingdom Fungi under the following:
(i) mode of nutrition
(ii) mode of reproduction
Ans.
Class
Mode of nutrition
Mode of reproduction
Phycomycetes
Saprophytic, parasitic or symbiotic
Asexual reproduction by zoospores or aplaospores, sexual reproduction may be isogamous, anisogamous or oogamous.
Ascomycetes
Mostly saprophytic; some parasitic
Asexual reproduction by conidia ; sexual reproduction by ascospores produced in asci
Basidiomy cetes
Mostly decomposers; some parasitic
Asexual spores generally absent ; sexual reproduction by basidiospores produced on basidia
Deuteromy cetes
Mostly saprophytic some parasitic
Only asexual reproduction is known; conidia are produced
10. What are the characteristic features of Euglenoids?
Ans. Euglenoids :
Majority of them are fresh water organisms found in stagnant water. Instead of a cell wall, they have a protein rich layer called pellicle which makes their body flexible.
They have two flagella, a short and a long one. Though they are photosynthetic in the presence of sunlight, when deprived of sunlight they behave like heterotrophs by predating on other smaller organisms. Interestingly, the pigments of euglenoids are identical to those present in higher plants. Example: Euglena
Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases.
Ans. Viruses are acellular infectious entities. They consist of genetic material surrounded by a protein coat called capsid. The capsid is made up of subunits called capsomeres.
The genetic material of viruses may be DNA or RNA. A virus generally contains only one type of nucleic acid. Some viruses also have an additional envelope around the capsid.
Four common viral diseases are:
Common cold
Influenza
Polio
AIDS
Organise a discussion in your class on the topic - Are viruses living or non-living?
Ans. Viruses show both living and non-living characteristics.
Living characteristics:
They contain genetic material in the form of DNA or RNA.
They reproduce inside a living host cell.
They can undergo mutation and evolution.
Non-living characteristics:
They are acellular.
They do not possess their own metabolic machinery.
Outside a living host cell, they remain inactive.
They can be crystallised.
Conclusion:
Viruses are considered to occupy a borderline position between living and non-living. They become active and multiply only inside a living host cell.
3.0NCERT Class 11 Biology – Chapter-Wise Solutions & Explanations
Access chapter-wise NCERT Solutions for Class 11 Biology with clear explanations for every textbook question. Understand important concepts, revise chapter topics, and prepare effectively for your Biology exams.
4.0Key Features of NCERT Solutions for Class 11 Biology Chapter 2
Basis of Classification: Understand the main criteria used in Whittaker's five-kingdom classification, including cell structure, body organisation, mode of nutrition, reproduction, and evolutionary relationships.
Comparison of Fungi: Learn the differences between Phycomycetes, Ascomycetes, Basidiomycetes, and Deuteromycetes based on their characteristics, structure, and methods of reproduction.
Viruses and Viroids: Understand the key differences between viruses and viroids, including their genetic material and the presence or absence of a protein coat.
Cyanobacteria and Nitrogen Fixation: Learn how specialised cells called heterocysts help certain cyanobacteria fix atmospheric nitrogen.
Kingdom-Wise Classification: Understand the important characteristics of Monera, Protista, Fungi, Plantae, and Animalia and the basis for placing organisms in each kingdom.
Prepared by Subject Experts: Solutions are prepared by ALLEN subject experts with accurate explanations based on the NCERT Class 11 Biology syllabus.