NCERT Solutions For Class 11 Biology Chapter 2 Biological Classification

Class 11 Biology Chapter 2 Biological Classification

NCERT Solutions For Class 11 Biology Chapter 2 Biological Classification in this step-by-step answer guide. In some of State Boards and CBSE schools, students are taught thru NCERT books. As the chapter comes to an end, students are requested few questions in an exercising to evaluate their expertise of the chapter. Students regularly want guidance managing those NCERT Solutions.

It’s most effective natural to get stuck withinside the exercises while solving them so that you can assist students score higher marks, we’ve provided step by step NCERT answers for all exercises of Class eleven Biology so you can are looking for assist from them. Students should solve those exercises carefully as questions withinside the final exams are requested from those, so these exercises immediately have an impact on students’ final score. Find all NCERT Solutions for Class eleven Biology below and prepare in your tests easily.

NCERT Solutions For Class 11 Biology Chapter 2 Biological Classification

Class 11 Biology Chapter 2 Biological Classification


Chapter 2 – Biological Classification

1. Discuss how classification systems have undergone several changes over a period of time.


Aristotle was the first to introduce the scientific classification. He used simple morphological characters to classify plants into trees, shrubs, and herbs. He divided the animals into two groups, one with red blood and one without.

Linnaeus introduced a two-kingdom classification, which includes Plantae and Animalia, respectively, of plants and animals. But this classification does not classify eukaryotes and prokaryotes, single-celled and multicellular organisms, photosynthetic (green algae) and non-photosynthetic (fungal) organisms. Therefore, the system was found to be less significant as it did not include more features.

Thus, the classification of living organisms has undergone several changes. R.H. Whittaker introduced five-kingdom classification, including Monera, Protista, Fungi, Plantae and Animalia. Some of the characteristics included in this classification – the structure of cells, body organization, mode of nutrition, mode of reproduction, and phylogenetic relationship to classify organisms. Subsequently, a three-domain system was proposed, which divided Kingdom Monera into two domains, leaving the remaining eukaryotic kingdoms in the third domain, thereby classifying the six kingdom.

2. State two economically important uses of:

(a) heterotrophic bacteria

(b) archaebacteria


a) Heterotrophic bacteria are used in the production of vitamins, antibiotics, cheese and curd.

They help fix nitrogen and are used in the formation of humus.

b) Archaebacteria are used in Biogas production.

They are used in the bioleaching of mines.

3. What is the nature of cell-walls in diatoms?


In diatoms, cell walls are embedded with silica imparting characteristic patterns onto the walls and are indestructible. These diatoms leave large amounts of cell wall deposits in their habitat to accumulate to form the diatomaceous earth.

4. Find out what do the terms ‘algal bloom’ and ‘red-tides’ signify.


Algal blooms are found in contaminated water. They are an overgrowth of algae, especially blue-green algae (cyanobacteria). Their growth leads to water pollution. They inhale carbon dioxide and exhale oxygen.

Rapid multiplication of red-pigmented dinoflagellates, such as Gonaulax, gives the sea a red color, a phenomenon known as red tides. These algae produce toxins that kill fish and other aquatic organisms.

5. How are viroids different from viruses?


(i) Viroids are small infectious agents with single-stranded RNA without a protein coat, but viruses have single-stranded or double-stranded RNA bound with protein-coat.

(ii) Viroids are very small in size compared to viruses.

(iii) Viroids infect only plants, while viruses infect plants, animals, and microorganisms.

6. Describe briefly the four major groups of Protozoa.


Four major groups of Protozoa are as follows

Amoeboid protozoans: Found in aquatic environment; they move and catch their prey using pseudopodia.

Flagellated protozoans: These protozoans are free-living or parasitic. Their locomotory structure is flagella.

Ciliated protozoans: They live in aquatic environments and the presence of cilia makes them actively moving.

Sporozoans: They contain a wide variety of organisms, producing infectious spores throughout their life cycle. Their spore-like phase helps them move from one host to another.

7. Plants are autotrophic. Can you think of some plants that are partially heterotrophic?


Insectivores and carnivores plants are partially heterotrophic, these organisms are green and autotrophic, but they prey and digest small components for their nitrogen supply.

Ex; Utricularia, Drosera, Nepenthes.

8. What do the terms phycobiont and mycobiont signify?


Lichens are a symbiotic association of fungi and algae. Phycobiont is part of algae and part of mycobiont fungi. Mycobiont provides structural cover that protects the algae from unfavorable conditions. Similarly, phycobionts prepare food by the process of photosynthesis, which is used by both organisms.

9. Give a comparative account of the classes of Kingdom Fungi under the following:

(i) mode of nutrition (ii) mode of reproduction







Mode of nutrition

Saprophytic or parasitic

Decomposers, Saprophytic or parasitic or coprophilous


Decomposers, Saprophytic or parasitic

Mode of reproduction

Asexual reproduction by zoospore (motile) Aplanospore (non-motile)

Sexual reproduction – zygote can be similar or dissimilar in morphology

Through asexual spores called conidia and sexual spores are known as ascospores

By vegetation reproduction through budding.

Fusion of two somatic cells for the formation of basidiospores is Plasmogamy

Through asexual spores called conidia.

10. What are the characteristic features of Euglenoids?


The typical features of Eugenoids are:

(i) Absence of cell wall.

(ii) Their body is flexible because there is a protein-rich layer called pellicle.

(iii) Two flagellas of different length are found.

(iv) They are autotrophic in the presence of sunlight and heterotrophic in the absence of sunlight.

11. Give a brief account of viruses with respect to their structure and nature of genetic material. Also name four common viral diseases.


Viruses are infectious agents that crystallize in structure when found outside the host cell. The genetic material is either DNA or RNA (never both) and they are located within the protein core. If the virus that infects plants has single-stranded RNA, then the viruses that infect animals are single or double-stranded DNA or RNA. Capsid is their protein coat, which in turn is made up of small subunits called capsomers, which protect nucleic acid.

Common viral diseases are –Influenza, AIDS, Herpes and Rabies.

12. Organise a discussion in your class on the topic – Are viruses living or nonliving?


Non-living Characters

(i) No cellular structure

(ii) They can be stored in bottles like crystals

(iii) There will be no energy storage or energy liberation systems

(iv) They cannot grow or multiply outside the host

Living characters

(i) They are host-specific

(ii) The presence of genetic material

(iii) The ability to multiply

(iv) They have antigenic properties

(v) They are obligate parasites

(vi) Mutations occur

Benefits of NCERT Solutions

NCERT’s Class 11 solution contains extremely important points, and for each chapter, each concept has been simplified to make it easier to remember and increase your chances of achieving excellent exam results. Exam Preparation References Here are some tips on how these solutions can help you prepare for the exam.

  1. This helps students solve many of the problems in each chapter and encourages them to make their concepts more meaningful.
  2. NCERT Solutions for Class 11 solutions encourage you to update your knowledge and refine your concepts so that you can get good results in the exam.
  3. These solutions are the best exam materials, allowing you to learn more about your week and your strengths. To get good results in the exam, it is important to overcome your weaknesses.
  4. Most of the questions in the exam are formulated in a similar way to NCERT textbooks. Therefore, students should review the solutions in each chapter in order to better understand the topic.
  5. It is free of cost.

Tips & Strategies for Class 11 Exam Preparation

  1. Plan your course and syllabus and make time for revision
  2. Please refer to the NCERT solution available on the cbsestudyguru website to clarify your concepts every time you prepare for the exam.
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  4. It is important to clear all your doubts before the exam with your teachers or Alex (an Al study Bot). 
  5. When you read or study a chapter, write down algorithm formulas, theorems, etc., and review them quickly before the exam.
  6. Practice an ample number of question papers to make your concepts stronger. 
  7. Take rest and a proper meal.  Don’t stress too much. 

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