NEET Biology Biological Classification Important Questions Set 01

These Class 11 NEET Biology important questions on Biological Classification give 45 questions with step-by-step answers, arranged as very short, short and long answer types, as asked in school and board examinations. They help NEET aspirants revise the definitions, structures, differences and key terms of the chapter.

Very Short Answer Type Questions

Question 1. What are monerans?
Answer: Unicellular prokaryotes

Question 2. Why some fungi are called 'fungi imperfecti'?
Answer: Because they lack perfect (sexual) stage.

Question 3. Who coined term virus?
Answer: Louis Pasteur

Question 4. Name the chemical substance present in the bacterial cell wall.
Answer: Peptidoglycan

Question 5. Expand TMV.
Answer: Tobacco Mosaic Virus

Question 6. Who classified plants into herbs, shrubs and trees?
Answer: Aristotle

Question 7. Who classified animals into Anaima and Enaima?
Answer: Aristotle

Question 8. Red tide causing organism belongs to which group of photosynthetic protists?
Answer: Dinoflagellates

Question 9. First scientific approach to classify the organisms was done by _________.
Answer: Aristotle

Question 10. Give the mode of nutrition in fungi.
Answer: Heterotrophic (Saprophytic/Parasitic)

Short Answer Type Questions

Question 11. According to two kingdom classification system, differentiate kingdom Plantae and Animalia in terms of cell wall, locomotion, nutrition and response to external stimuli.

Answer:

Question 12. Write down three drawbacks of two-kingdom classification system.

Answer:

This system did not distinguish between :

(i) Unicellular and multicellular organisms.

(ii) Eukaryotes and prokaryotes.

(iii) Photosynthetic (green algae) and non-photosynthetic (fungi) organisms.

Question 13. In which kingdom, Whittaker placed Chlamydomonas and Chlorella? What was the earlier position of these organisms in two-kingdom system?
Answer: He included them under kingdom Protista and earlier these were placed in Algae within plants and both having cell walls.

Question 14. Why do we expect the criteria of classification to change in the future?
Answer: As our understanding of characteristics and evolutionary relationship improve, we expect changes in classification to occur.

Question 15. Which type of similarities are reflected in existing classification system?
Answer: This existing classification reflects not only the morphological, physiological and reproductive similarities, but is also phylogenetic i.e. based on evolutionary relationship.

Question 16. What are the sole members of the kingdom Monera and mention about their habitat?
Answer: Bacteria are the sole members of kingdom Monera. They live everywhere and also in extreme habitats like hot springs, deserts, snow and deep oceans.

Question 17. Give a characteristic feature of kingdom Monera, in terms of their nucleus and cell wall (composition).

Answer:

(i) Nucleoid or incipient nucleus is composed of naked DNA, RNA and non-histone proteins.

(ii) Cell wall is made up of peptidoglycan except in Archaebacteria.

Question 18. Which type of nutrition and reproduction is found in kingdom Monera?

Answer:

Sole members of kingdom Monera are bacteria in which some are autotrophic and vast majority are heterotrophic.

They reproduce mainly by fission. Sometimes they produce spores under unfavourable conditions.

Question 19. How are bacteria grouped on the basis of their shape?

Answer:

(i) The spherical coccus (pl.: cocci).

(ii) The rod-shaped Bacillus (pl.: bacilli).

(iii) The comma-shaped vibrium (pl.: vibrio).

(iv) The spiral spirillum (pl.: spirilla).

Question 20. Why Archaebacteria are special?
Answer: Archaebacteria are special as they live in some of the harsh habitat such as extreme salty area (halophiles), hot springs (thermoacidophiles) and marshy areas (methanogens).

Question 21. Which feature of Archaebacteria allow them to survive in extreme conditions?
Answer: They (Archaebacteria) can survive in extreme conditions because of their different cell wall structure.

Question 22. Give two example of Methanogens, Halophiles and Thermoacidophiles.

Answer:

Methanogens :

(i) Methanococcus

(ii) Methanobacterium

Halophiles :

(i) Halobacterium

(ii) Halococcus

Thermoacidophiles :

(i) Thermoplasma

(ii) Thermoproteus

Question 23. How are bacteria classified on the basis of their mode of nutrition?

Answer:

Bacteria

Question 24. Why are cyanobacteria called photosynthetic autotrophs?
Answer: Cyanobacteria are also known as blue-green algae. They have chlorophyll, similar to the chlorophyll present in plants which help them to perform photosynthesis. Hence, they are known as photosynthetic autotrophs.

Question 25. In which habitat cyanobacteria exist? Give their effect on aquatic animals.
Answer: These live in marine and terrestrial conditions. They cause algal bloom in polluted water. They also deplete the oxygen from the water reservoir and thereby cause large scale death of the aquatic animals.

Question 26. Why chemosynthetic bacteria oxidise inorganic substances?
Answer: They oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production.

Question 27. Write a note on the uses of heterotrophic bacteria.
Answer: These are most abundant in nature. The majority are important decomposers. 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 etc.

Question 28. Mention the damage caused by pathogenic bacteria to human beings.
Answer: They cause damage to human beings, crops, farm animals and pets. Cholera, typhoid, tetanus, citrus canker are the well-known diseases caused by different bacteria.

Question 29. Write a note on Mycoplasma.
Answer: The mycoplasma are organisms that completely lack a cell wall. They are smallest living cells known and can survive without oxygen. Many mycoplasma are pathogenic i.e. cause various diseases in plants, animals and human beings.

Question 30. Discuss the habitat and mode of nutrition of chrysophytes.
Answer: Chrysophytes include diatoms and golden algae (desmids). They are found both in fresh and marine water. They are microscopic and float passively in water currents. Most of these members are autotrophic (i.e. photosynthetic).

Long Answer Type Questions

Question 31. Give five features of dinoflagellates and their impact on marine ecosystem.

Answer:

(i) They are photosynthetic protists.

(ii) Most of them are marine.

(iii) They may appear red, yellow, green, brown or blue depending upon the main pigment present in their cells.

(iv) The cell wall has stiff cellular plates on the outer surface.

(v) Most of them have two flagella.

Impact :

(i) Very often, the red dianoflagellates undergo rapid multiplication and make the sea to appear red causing the 'red tide'.

(ii) Some dianoflagellates are poisonous to vertebrates. When they are in large number, they produce the toxin into the sea water which kills fishes and other aquatic animals.

Question 32. (a) Write a note on the mode of nutrition in Euglena.
(b) Explain the reproduction in Euglena.

Answer:

(a) Euglena shows mixotrophic type of nutrition. Generally, Euglena shows autotrophic type of nutrition but during prolonged darkness, it obtains nutrition from dead and decaying substances. It has more than one type of mode of nutrition, hence it is mixotrophic.

(b) In Euglena, asexual reproduction takes place by longitudinal fission starting at flagellar end. The flagellum is duplicated before the cell divides.

Question 33. (a) How do slime moulds aggregate?
(b) How do slime moulds form fruiting bodies and how they are extremely resistant?

Answer:

(a) They are saprophytic protists. Their body moves along decaying twigs and leaves by engulfing organic material. Under favourable conditions, they form an aggregation called plasmodium which may grow and spread over several feet.

(b) During unfavourable conditions, the plasmodium differentiates and forms fruiting bodies bearing spores at their tips. These spores have true walls. They are extremely resistant and survive for many years, even under adverse conditions.

Question 34. (a) Mention the diversity of fungi.
(b) Give an account of their habitat.
(c) Why they are regarded as heterotrophs?
(d) In what way they are useful?
(e) What is mycorrhiza?

Answer:

(a) Fungi include diverse organisms which range in structure from unicellular yeasts to highly complex edible mushrooms, non-edible toad stools.

(b) They are cosmopolitan in occurrence being present in air, water, soil and on the animals and plants. They are more abundant in warm and humid areas.

(c) They are unable to manufacture their own food because of the absence of chlorophyll. Therefore, they are regarded as heterotrophs.

(d) They are (yeast) are used in making bread and beer. Some fungi are also useful in preparing antibiotics as penicillin.

(e) The association of fungi with the roots of higher plants is called mycorrhiza.

Question 35. (a) Discuss fragmentation, budding and fission in fungi.
(b) What is coenocytic hyphae?

Answer:

(a) Reproduction in fungi occurs by fragmentation, budding and fission.

In fragmentation, the mycelium breaks up into two or more segments due to mechanical injury, decay etc. Each fragment grows to form the complete mycelium.

In budding (e.g. yeast), the parent cell shows protrusion at one end. The protrusion grows into a bud which ultimately separates as a new individual.

In fission, the unicellular fungus like yeast divides into two daughters through division or fission of the cell.

(b) Some hyphae are continuous tubes filled with multinucleated cytoplasm, these are called coenocytic hyphae.

Question 36. Explain sexual reproduction in Basidiomycetes and give three examples of this group.

Answer:

In Basidiomycetes, the sex organs are absent, but plasmogamy is brought about by fusion of two vegetative or somatic cells of genetically different strains. The resultant structure is dikaryotic which give rise to basidium, where karyogamy and meiosis take place. Two compatible nuclei fuse to form zygote, which undergoes meiosis and forms four basidiospores. So, the sexual spores called basidiospores are generally four in number. They are exogenous (i.e. produced outside the body). The fruiting body containing basidia is a multicellular structure called basidiocarp.

Examples : Agaricus, Ustilago and Puccinia.

Question 37. (a) Why some fungi were grouped under Deuteromycetes?
(b) Why the fungi imperfecti were moved into classes Ascomycetes and Basidiomycetes?
(c) How these fungi reproduce asexually?
(d) What is the mode of nutrition in members of Deuteromycetes and how some of them help in mineral cycling?

Answer:

(a) There is only asexual and vegetative phase known, so these are commonly regarded as imperfect fungi. Hence, they were placed under class deuteromycetes.

(b) By the establishment of linkages, when the perfect stage (or sexual form) of these fungi were discovered, they were moved out of deuteromycetes to ascomycetes and basidiomycetes.

(c) The deuteromycetes reproduce by asexual spores known as conidia.

(d) Some of them are saprophytes or parasites while large number of them are decomposers of litter (organic matter) and help in mineral cycling.

Question 38. (a) Explain alternation of generation in kingdom Plantae.
(b) Do few members of kingdom Plantae have partially heterotrophic mode of nutrition, if yes, then give example?
(c) Differentiate between kingdom Plantae and Animalia on the basis of growth pattern.

Answer:

(a) In plants, life cycle has two distinct phases i.e. the diploid sporophytic and haploid gametophytic that alternate with each other. This phenomenon is called alternation of generation.

(b) Few members of kingdom Plantae are partially heterotrophic such as insectivorous plants e.g. bladderwort and venus fly tap or parasite like Cuscuta.

(c) The members of animal kingdom follow definite growth pattern and grow into adult that have a definite shape and size which in case of plants growth is irregular.

Question 39. Give the contribution of D.J. Ivanowsky, M.W. Beijerinck and W.M. Stanley for studying viruses.

Answer:

D.J. Ivanowsky (1892) recognised certain microbes which is the causal organism of the mosaic disease of tobacco. These were found to be smaller than bacteria because they passed through bacteria-proof filters. M.W. Beijerinek (1898) demonstrated that the extract of the infected plants of tobacco could cause infection in healthy plants and called this fluid as Contagium vivum fluidum (infectious living fluid).

W.M. Stanley (1935) crystallised TMV (Tobacco Mosaic Virus) for the first time. He showed that viruses could be crystallised and crystal consists largely of proteins.

Question 40. (a) What is bacterial virus?
(b) What is advantage of capsomeres?
(c) Do viruses have their own genetic material?
(d) Name the infectious part of virus.

Answer:

(a) Bacterial viruses or bacteriophages are the viruses that infect the bacteria.

(b) Viruses have protein coat called capsid made of small subunits called capsomers for the protection of nucleic acid.

(c) In addition to proteins, viruses also have their own genetic material in the form of RNA or DNA.

(d) The infectious part of viruses is genetic material.

Question 41. Tabulate the characteristics of five kingdom, on the basis of cell type, cell wall, nuclear membrane, body organisation and mode of nutrition.
Answer: Five Kingdoms Characters Monera Protista Fungi Plantae Animalia Cell type Prokaryotic Eukaryotic Eukaryotic Eukaryotic Eukaryotic Cell wall Non-cellular Present in some Present Present Absent (Polysaccharide + (without (cellulose) amino acid) cellulose) Nuclear Absent Present Present Present Present membrane Body Cellular Cellular Multicellular/ Tissue/organ Tissue/organ/ organisation loose tissue organ system Mode of Autotrophic Autotrophic Heterotrophic Autotrophic Heterotrophic nutrition (chemosynthetic and (Photosynthetic) (Saprophytic/ (Photosynthetic) (Holozoic/ photosynthetic) and and Parasitic) Saprophytic Heterotrophic Heterotrophic etc.) (saprophyte/parasite)

Question 42. (a) Write a short note on methanogens.
(b) Write the shape of Coccus, Bacillus, Vibrio and Spirillium type of bacteria.

Answer:

(a) These bacteria are of marshy habitat. They are capable of converting CO₂, methanol and formic acid into methane so named methanogens. These methanogens are present in the guts of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals.

Example : Methanococcus, Methanobacterium etc.

(b) (i) Coccus : Spherical

(ii) Bacillus : Rod-shaped

(iii) Vibrio : Comma-shaped

(iv) Spirillum : Spiral-shaped

Question 43. What are halophiles?

Answer:

These bacteria live in extreme saline environment such as salt lakes, sea, brines etc.

In strong light, these halophiles develop a pigmented membrane (purple membrane) composed of a pigment called bacterio-rhodopsin to harness the sun's energy. The light energy is utilised to carry on ATP production but not for food synthesis.

Example : Halobacterium and Halococcus.

Question 44. Write an explanatory note on thermoacidophiles.
Answer: These are capable of tolerating high temperature as well as high acidity and hence, the name thermoacidophiles. They often live in hot water springs where the temperature is as high as 80°C and the pH as low as 2. They oxidise sulphur to sulphuric acid under aerobic conditions and the energy obtained in this reaction is utilised for the synthesis of organic food. The medium becomes highly acidic due to the production of sulphuric acid. Under anaerobic conditions sulphur is reduced to H₂S, hence these are chemosynthetic in nature. Example : Thermoplasma, Thermoproteus etc.

Question 45. Write a note on :
(a) Mycorrhiza
(b) Sac fungi
(c) Imperfect fungi

Answer:

(a) The symbiotic association of a fungus with the root of higher plant is called Mycorrhiza.

(b) Ascomycetes are commonly known as sac-fungi. They are unicellular or multicellular. Sac like ascus contains ascospores.

(c) Deuteromycetes are known as imperfect fungi because only the asexual or vegetative phases of these fungi are known.