Category: Important Questions

Students get through the TN Board 11th Bio Botany Important Questions Chapter 1 Living World which is useful for their exam preparation.

TN State Board 11th Bio Botany Important Questions Chapter 1 Living World

Answer the following short answers.

Question 1.
Define Biosphere.
Answer:
Earth has formed some 4.6 billion years ago. It is a life-supporting planet with landforms like mountains, plateaus, glaciers, etc., Life on earth exists within a complex structure called the biosphere.

Question 2.
What is the role of the DNA molecule?
Answer:
DNA is essential for the regulation of life and is made up of carbon, hydrogen, oxygen, nitrogen, and phosphorus, and thus nonliving and living things exist together to make our planet unique.

Question 3.
What is consciousness?
Answer:
AH organisms are capable of sensing their environment and respond to various physical, chemical, and biological stimuli. Animals sense their surroundings by sense organs. This is called consciousness.

Question 4.
Explain Prions.
Answer:
Prions were discovered by Stanley B.Prusiner in the year 1982 and are proteinaceous infectious particles. They are the causative agents for about a dozen fatal degenerative disorders of the central nervous system of humans and other animals. For example Creutzfeldt – Jakob Disease (CJD), Bovine Spongiform Encephalopathy (BSE) – commonly known as mad cow disease and scrapie disease of sheep.

Question 5.
What is Plasmid?
Answer:
Plasmids are extrachromosomal double-stranded, circular, self-replicating, autonomous elements. They contain genes for fertility, antibiotic-resistant and heavy metals. It also helps in the production of bacteriocins and toxins which are not found in the bacterial chromosome.

Question 6.
Mention the need for classification?
Answer:
Classification is essential to achieve the following needs:

1. To relate things based on common characteristic features.
2. To define organisms based on the salient features.
3. Helps in knowing the relationship amongst different groups of organisms.
4. It helps in understanding the evolutionary relationship between organisms.

Question 7.
What is Pili?
Answer:
Pili or fimbriae are hair-like appendages found on the surface of the cell wall of gram-negative bacteria (eg. Enterobacterium). The pili are 0.2 to 20 pm long with a diameter of about 0.025pm. In addition to normal pili, special types of pili that help in conjugation called sex pili are also found.

Question 8.
Define “Pruteen”.
Answer:
“Pruteen” is a single cell protein derived from Methylophilus and Methylotropus.

Question 9.
What are Mycobiont and Phycobiont?
Answer:
The symbiotic association between algae and fungi is called lichens. The algal partner |is called Phycobiont or Photobiont and the fungal partner is called Mycobiont. Algae provide nutrition for fungal partners in turn fungi provide protection and also help to fix the thallus to the substratum through rhizines. Asexual reproduction takes place through fragmentation, Soredia, and Isidia. Phycobionst reproduces by akinetes, hormogonia, aplanospore, etc., Mycobionts undergo sexual reproduction and produce ascocarps.

Question 10.
Define Homeostasis.
Answer:
Property of self-regulation and tendency to maintain a steady-state within an external environment which is liable to change is called Homeostasis. It is essential for the living organism to maintain internal conditions to survive in the environment.

Question 11.
Mention any four living characteristics of viruses.
Answer:

1. Presence of nucleic acid and protein.
2. Capable of mutation
3. Ability to multiply within living cells.
4. Able to infect and cause diseases in living beings.

Question 12.
Explain the term Viroid.
Answer:
Viroid is a circular molecule of ssRNA without a capsid and was discovered by T.O.Diener in the year 1971. The RNA of viroid has a low molecular weight. Viroids cause citrus exocytic and potato spindle tuber disease in plants.

Question 13.
What is meant by red tide?
Answer:
Red tide is caused by the toxic bloom of Dinoflagellates like Gymnodinium breve and Gonyaulax tamarensis. A major red tide incident in the west coast of Florida in the year 1982 killed hundreds and thousands of fishes.

Question 14.
What are Polysomes?
Answer:
The ribosomes are the site of protein synthesis. The number of ribosomes per cell varies from 10,000 to 15,000. The ribosomes are 70S type and consist of two subunits (50S and 30S). The ribosomes are held together by mRNA and form polyribosomes or polysomes.

Question 15.
Write briefly on purple sulfur bacteria.
Answer:
For bacteria belonging to this group, the hydrogen donor is Thiosulphate and Bacteriochlorophyll. Chlorophyll containing chlorosomes are present, eg. Chromatium.

Question 16.
Match the following:

(i) Xanthomanas oryzae	(a) Apple
(ii) Erwiria caratovora	(b) Citrus
(iii) Erwiria amylovera	(c) Rice
(iv) Xanthomnas citri	(d) Carrot

Answer:
(i)-(c);
(ii)-(a);
(iii)-(d);
(iv)-(b)

Question 17.
What is meant by aflatoxin?
Answer:
Aspergillus, Rhizopus, Mucor, and Penicillium ate involved in the spoilage of food materials. Aspergillus flavus infest dried foods and produce a carcinogenic toxins called aflatoxin.

Question 18.
Explain the term mycorrhizae.
Answer:
The Symbiotic association between fungal mycelium and roots of plants is called mycorrhizae. In this relationship, fungi absorb nutrition from the root, and in turn, the hyphal network of mycorrhizae forming fungi helps the plant to absorb water and mineral nutrients from the soil.

Question 19.
Name any two fungal diseases of plants and their causative organism.
Answer:

1. A blast of Paddy: Magnaporthe grisea.
2. Red rot of sugarcane: Colletotrichum falcatum.

Question 20.
Explain Oomycetes with an example.
Answer:
Coenocytic mycelium is present. The cell wall is made up of Glucan and Cellulose. Zoospore with one whiplash and one tinsel flagellum is present. Sexual reproduction is Oogamous. eg. Albugo.

Answer In brief.

Question 1.
Differentiate extrinsic and intrinsic.
Answer:

Extrinsic	Intrinsic
Growth in non-living objects is extrinsic.	Growth in living things is intrinsic.
Mountains, boulders, and sand mounds grow by simple aggregation of material on the surface.	Living cells grow by the addition of new protoplasm within the cells.

Question 2.
List out the classification of viruses.
Answer:

Different Classes of viruses
Class	Example
Class 1 – Viruses with dsDNA	Adenoviruses
Class 2 – Viruses with (+) sense ssDNA	Parvo viruses
Class 3 – Viruses with dsRNA	Reo viruses
Class 4 – Viruses with (+) sense ssRNA	Toga viruses
Class 5 – Viruses with (-) antisense ssRNA	Rhabdo viruses
Class 6 – Viruses with (+) sense ss RNA- RT that replicate with DNA intermediate in the life cycle.	Retroviruses
Class 7 – Viruses with ds DNA – RT that replicate with RNA intermediate in the life cycle.	Hepadna viruses

Question 3.
Name any three plant, animal, and human diseases caused by viruses.
Answer:
Plant diseases: (i) Tobacco mosaic, (ii) Cauliflower mosaic, (iii) Sugarcane mosaic.
Animal diseases: (i) Foot and mouth disease of cattle, (ii) Rabies of dog, (iii) Encephalomyelitis of horse
Human diseases: (i) Common cold, (ii) Hepatitis B, (iii) Cancer.

Question 4.
Distinguish catabolism and anabolism.
Answer:

Anabolism	Catabolism
Building up process.	Breaking down process.
Smaller molecules combine together to form larger molecules.	Larger molecules break into smaller units.
Chemical energy is formed and stored, eg. Synthesis of proteins from amino acids.	The stored chemical energy is released and used. eg. Breaking down of glucose to C02 and water.

Question 5.
List out any three methods of sexual reproduction, in fungi.
Answer:

1. Sexual reproduction is present but sex organs are absent. Somatogamy or spermatisation results in plasmogamy.
2. Karyogamy is delayed and the dikaryotic phase is prolonged.
3. Karyogamy takes place in basidium and it is immediately followed by meiotic division.

Question 6.
Describe briefly the Viral genome.
Answer:

1. Each virus possesses only one type of nucleic acid either DNA or RNA. The nucleic acid may be in a linear or circular form.
2. Generally nucleic acid is present as a single unit but in wound tumor virus and in influenza virus it is found in segments.
3. The viruses possessing DNA are called ‘Deoxyviruses’ whereas those possessing RNA are called ‘Riboviruses’. The majority of animal and bacterial viruses are DNA viruses (HIV is the animal virus that possesses RNA).
4. Plant viruses generally contain RNA (Cauliflower Mosaic virus possesses DNA). The nucleic acids may be single-stranded or double-stranded. On the basis of the nature of nucleic acid, viruses are classified into four categories. They are Viruses with ssDNA (Parvoviruses), dsDNA (Bacteriophages), ssRNA (TMV), and dsRNA(wound tumour virus).

Question 7.
Explain the structure of T₄ bacteriophage.
Answer:

1. The T₄ phage is tadpole-shaped and consists of head, collar, tail, base plate, and fibers.
2. The head is hexagonal which consists of about 2000 identical protein subunits.
3. The long helical tail consists of an inner tubular core that is connected to the head by a collar.
4. There is a base plate attached to the end of the tail. The base plate contains six spikes and tail fibers. These fibers are used to attach the phage to the cell wall of the bacterial host during replication.
5. A dsDNA molecule of about 50 pm is tightly packed inside the head. The DNA is about 1000 times longer than the phage itself.

Question 8.
Draw and label the ultrastructure of a bacterial cell.
Answer:

Question 9.
What is meant by Ammonification? Explain the bacteria involved in the process.
Answer:

Bacterial aspects	Bacteria	Role
Ammonification	(i)  Bacillus ramosus (ii)  Bacillus mycoides	Convert complex proteins in the dead bodies of plants and animals into ammonia which is later converted into ammonium salt

Question 10.
Explain Actinomycetes with an example.
Answer:
Actinomycetes are also called ‘Ray fungi’ due to their mycelia-like growth. They are anaerobic or facultative anaerobic microorganisms and are gram-positive. They do not produce an aerial mycelium. Their DNA contains high guanine and cytosine content (eg. Streptomyces).

Answer In detail.

Question 1.
Draw the structure of different types of viruses and explain.
Answer:
Viruses are ultramicroscopic particles. They are smaller than bacteria and their diameter range from 20 to 300 nm (1 nm = 10^-9 meters). Bacteriophage measures about 10 – 100 nm in size. The size of TMV is 300 x 20 nm.
Generally, viruses are of three types based on shape and symmetry.

1. Cuboid symmetry – eg. Adenovirus, Herpes virus.
2. Helical symmetry – eg. Influenza virus, TMV.
3. Complex or Atypical – eg. Bacteriophage, Vaccinia virus.

Question 2.
Explain the types of Respiration in Bacteria.
Answer:
Two types of respiration are found in Bacteria. They are (i) Aerobic respiration, (ii) Anaerobic respiration.

1. Aerobic respiration These bacteria require oxygen as a terminal acceptor and will not grow under anaerobic conditions (i.e. in the absence of O2) eg. Streptococcus.
   Obligate aerobes: Some Micrococcus species are obligate aerobes (i.e. they must have oxygen to survive),
2. Anaerobic respiration: These bacteria do not use oxygen for growth and metabolism but obtain their energy from fermentation reactions, eg. Clostridium.

Facultative anaerobes: There are bacteria that can grow either using oxygen as a terminal electron acceptor or anaerobically using fermentation reaction to obtain energy. When a facultative anaerobe such as E. coli is present at a site of infection like an abdominal abscess, it can rapidly consume all available 02 and change to anaerobic metabolism producing an anaerobic environment and thus allow the anaerobic bacteria that are present to grow and cause disease, eg. Escherichia coli and Salmonella.
Capnophilic Bacteria: Bacteria that require CO₂ for their growth are called as capnophilic bacteria, eg. Campylobacter.

Question 3.
Describe the various steps in Gram’s staining procedure.
Answer:

Question 4.
Give a concise account of asexual reproduction in bacteria.
Answer:
Bacteria reproduce asexually by Binary fission, conidia, and endospore formation. Among these Binary fission is the most common one.
Binary fission: Under favorable conditions, the cell divides into two daughter cells. The nuclear material divides first and it is followed by the formation of a simple median constriction which! finally results in the separation of two cells.
Endospores: During unfavorable conditions bacteria produce endospores. Endospores are produced in Bacillus megaterium, Bacillus sphaericus, and Clostridium tetani. Endospores are thick-walled resting spores. During the favorable conditions, they germinate and form bacteria.

Question 5.
Enumerate the general characteristic features of fungi.
Answer:

1. The majority of fungi are made up of thin, filamentous branched structures called hyphae. A number of hyphae get interwoven to form mycelium. The cell wall of fungi is made up of a polysaccharide called chitin (polymer of N-acetyl glucosamine).
2. The fungal mycelium is categorized into two types based on the presence or absence of septa (figure). In lower fungi, the hypha is aseptate, multinucleate and is known as coenocytic mycelium (eg. Albugo). In higher fungi, a septum is present between the cells of the hyphae. eg. Fusarium:
   
3. The mycelium is organized into loosely or compactly interwoven fungal tissues called plectenchyma. It is further divided into two types prosenchyma and pseudoparenchyma. In the former type, the hyphae are arranged loosely but parallel to one another In the latter hyphae are compactly arranged and lose their identity.
4. In holocarpic forms, the entire thallus is converted into reproductive structure whereas in Eucarpic some regions of the thallus are involved in the reproduction other regions remain vegetative. Fungi .reproduce both by asexual and sexual methods. The asexual phase is called Anamorph and the sexual phase is called Teleomorph. Fungi having both phases are called Holomorph.
5. In general sexual reproduction in fungi includes three steps (a) Fusion of two protoplasts (plasmogamy), (b) Fusion of nuclei (karyogamy), and (c) Production of haploid spores through meiosis.

Question 6.
Write an essay on the Beneficial activities of fungi.
Answer:
Fungi provide delicious and nutritious food called mushrooms. They recycle the minerals by decomposing the litter thus adding fertility to the soil. The dairy industry is based on a single-celled fungus called yeast. They deteriorate the timber. Fungi cause food poisoning due to the production of toxins. The Beneficial and harmful activities of fungi are discussed below:
Beneficial activities:

1. Food: Mushrooms likeLentinus edodes, Agaricusbisporus, Volvariella volvaceae are consumed ‘ for their high nutritive value. Yeasts provide vitamin B and Eremothecium ashbyii is a rich source of Vitamin B₁₂.
2. Medicine: Fungi produce antibiotics that arrest the growth or destroy the bacteria. Some of the antibiotics produced by fungi include Penicillin (Penicillium notatum), Cephalosporins,
   (Acremonium chrysogenum), Griseofulvin (Penicillium griseofulvum). Ergot alkaloids (Ergotamine) produced by Claviceps purpurea are used as vasoconstrictors.
3. Industries: Production of organic acid: For the commercial production of organic acids fungi are employed in the Industries. Some of the organic acids and fungi which help in the production of organic acids are Citric acid and Gluconic-acid – Aspergillus niger, Itaconic acid – Aspergillus terreus, Kojic acid – Aspergilhis oryzae.
4. Bakery and Brewery: Yeast (Saccharomyces cerevisiae) is used for the fermentation of sugars to yield alcohol. Bakeries utilize yeast for the production of Bakery products like Bread, buns, rolls. etc. Penicillium roquefortii and Penicillium camemberti are employed in cheese production.
5. Production of enzymes: Aspergillus oryzae, Aspergillus niger is employed in the production of enzymes like Amylase, Protease, Lactase etc., ’Rennet’ which helps in the coagulation of milk in cheese manufacturing is derived from Mucor spp.
6. Agriculture: Mycorrhiza forming fungi like Rhizoctonia, Phallus, Scleroderma helps in the absorption of water and minerals. Fungi like Beauveria bassiana, Metarhizium anisopliae are used as Biopesticides to eradicate the pests of crops. Gibberellin, produced by a fungus Gibberella fujikuroi induce plant growth and is used as growth promoter.

Activity

Text Book Page No. 25

Collect some root nodules of leguminous crops. Draw diagram. Wash, it in tap water and prepare d smear by squeezing the content into a clean slide. Follow the Gram staining method and identify the bacteria.
Answer:
Azotobacter, Clostridium, rhizobium are observed.

Text Book Page No. 37

Get a button mushroom. Draw a diagram of the fruit body. Take a thin longitudinal section passing through the gill and observe the section under a microscope. Record your observations.
Answer:


Keep a slice of bread in a clean plastic tray or plate. Wet the surface with little water. Leave the setup for 3 or 4 days. Observe the moldy growth on the surface of the bread. Using .a needle removes some mycelium and place it on a slide and stain the mycelium using lactophenol blue. Observe the mycelium and sporangium under the microscope and Record your observation and identify the fungi and its group based on characteristic features:
The bread mold fungi such as Mucor, Rhizopus can be observed.

I. Choose the correct answer.

1. A sexual reproduction in living organism occurs by the production of:
(a) conidia formation
(b) budding
(c) binnary fission
(d) all the above
Answer:
(d) all the above

2. Animal sense their surroundings by sense organ is called:
(a) Metabolism
(b) Irritability
(c) Consciounsness
(d) Anabolism
Answer:
(c) Consciounsness

3. Who obtained the crystalline protein sediment from infected tobacco juice?
(a) Edward Jennev
(b) W.M. Stanley
(c) Ivanowsky
(d) F.W. Twort
Answer:
(b) W.M. Stanley

4. Which of the following is the diameter of bacteriophage?
(a) 10 – 100 nm
(b) 20 – 100 nm
(c) 10 – 200 nm
(d) 20 – 30 nm
Answer:
(a) 10 – 100 nm

5. How many classes are there in viruses?
(a) 5
(b) 3
(c) 1
(d) 6
Answer:
(c) 1

6. The shape of TMV is:
(a) round shape
(b) cuboid shape
(c) cylindrical shape
(d) rod shape
Answer:
(d) rod shape

7. Identify the incorrect statement of living characters of viruses.
(a) Absence of metabolism
(b) Presence of nucleic acid
(c) Multiply within the cells
(d) Capable of mutation
Answer:
(a) Absence of metabolism

8. Cyanophages means:
(a) Viruses infecting red algae
(b) Viruses infecting brown algae
(c) Viruses infecting blue-green algae
(d) Viruses infecting green algae
Answer:
(c) Viruses infecting blue-green algae

9. Which one of the following is a bacterial disease?
(a) Common cold
(b) Cancer
(c) Rabies
(d) Tetanus
Answer:
(d) Tetanus

10. Who proposed the five kingdom classification?
(a) R.H. Whittaker
(b) Linnaeus
(c) Haeckel
(d) Aristotle
Answer:
(a) R.H. Whittaker

11. Actinomycetes, cyanobacteria are examples of:
(a) Protostar
(b) Fungi
(c) Monera
(d) Animalia
Answer:
(c) Monera

12. What are the three domains of life according to Carl Woese and co-workers?
(a) Prokaiyota, Eukaryota, Archaea
(b) Archaea, Bacteria, Protozoa
(c) Archaea, Fungi, Bacteria
(d) Bacteria, Archaea, Eukarya
Answer:
(d) Bacteria, Archaea, Eukarya

13. Who coined the word Bacterium?
(a) Christian Gram
(b) C.G.Ehrenberg
(c) Griffith
(d) Lederberg
Answer:
(b) C.G.Ehrenberg

14. Eschrichia coli and Salmonella are examples of:
(a) Aerobes
(b) Obligate aerobes
(c) Facultative anaerobes
(d) Anaerobes
Answer:
(c) Facultative anaerobes

15. Which among the bacteria breakdown hydrocarbons?
(a) Pseudomonas putida
(b) Lacto bacillus
(c) Bifido bacterium
(d) Nitrosomonas
Answer:
(a) Pseudomonas putida

16. Match the following disease with their pathogen:

Name of the disease	Name of the pathogen
(i) Bacterial blight	(a) Clavibactor michiganensis
(ii) Fire blight	(b) Xanthomonas citri
(Hi) Citrus canker	(c) Xanthomonas oryzae
(iv) Ring rot	(d) Erwinia amylvora

(a) (i)-(d); (ii)-(c); (iii)-(b); (iv)-(a)
(b) (i)-(c); (ii)-(a); (iii)-(b); (iv)-(d)
(c) (i)-(a)-, (ii)-(d); (iii)-(b); (iv)-(c)
(d) (i)-(c); (ii)-(d); (iii)-(b); (iv)-(a)
Answer:
(d) (i)-(c); (ii)-(d); (iii)-(b); (iv)-(a)

17. PHB means:
(a) Poly Hexo Butyrate
(b) Poly Hydrolxl Butyle
(c) Poly -13 Hydroxl Butyrate
(d) Poly Hedfal Butyrate
Answer:
(c) Poly -13 Hydroxl Butyrate

18. Which of the statement is incorrect in blue-green algae?
(a) The thallus is unicellular
(b) The reserve food material is cyanophycean starch
(c) Absence of mucilage around the thallus
(d) Sexual reproduction is absent
Answer:
(c) Absence of mucilage around the thallus

19. Nostoc and Anabaena are examples of:
(a) Biofertilizer
(b) Biological fuel
(c) Biotic factor
(d) Pro-Biotic
Answer:
(a) Biofertilizer

20. Father of the Indian mycology is:
(a) P.A.Michali
(b) C.H.Blackley
(c) Sir Edwin John Butler
(d) A.F. Blakeshec
Answer:
(c) Sir Edwin John Butler

21. In Fungi reproduction sexual phase is called:
(a) Anamorph
(b) Holomorph
(c) Allelomorph
(d) Teleomorph
Answer:
(d) Teleomorph

22. Odd one out (Type of ascocarp):
(a) Deistothecium
(b) Perithecium
(c) Apothecium
(d) Basidium
Answer:
(d) Basidium

23. Which one of the following is a rich source of vitamin B12?
(a) Agaricus bisporus
(b) Aspergillus oryzae
(c) Eremothecium ashbyii
(d) Clavicepspurpurea
Answer:
(c) Eremothecium ashbyii

24. Pick out the incorrect pair:
(a) Blast of paddy – Magnaporthe grisea
(b) Red rot of sugarcane – Albugo Candida
(c) Rust of wheat – Pucciniagraminis
(d) peach of leaf curl – Taphrina deformans
Answer:
(b) Red rot of sugarcane – Albugo Candida

25. The symbiotic association between fungal mycelium and roots of higher plants is called:
(a) Lichen
(b) Symbiotic
(c) Monotropa
(d) Mycorrhizac
Answer:
(d) Mycorrhizac

26. Each virus posses only one type of nucleic acid:
(a) Either DNA or RNA
(b) DNA only
(c) Neither DNA nor RNA
(d) RNA only
Answer:
(a) Either DNA or RNA

27. Tobacco mosaic virus is a:
(a) rhomboid-shaped helical virus
(b) rod-shaped helical virus
(c) rectangular-shaped virus
(d) triangular shaped helical virus
Answer:
(b) rod-shaped helical virus

28. Indicate the correct statement:
(a) Virion is a circular molecule of ss RNA without a capsid
(b) Virion is a phage that injects linear DNA into the host cell
(c) Virion is an intact infective virus particle, which is non – replicating outside a host cell
(d) Virion is discovered by J.W Randles
Answer:
(c) Virion is an intact infective virus particle, which is non – replicating outside a host cell

29. Transfer of DNA from one bacterium to another is called:
(a) Conjugation
(b) Transformation
(c) Transduction
(d) Binary fission
Answer:
(b) Transformation

30. Fusion of two somative cells of the hypae is called:
(a) Anisogamy
(b) Somatogamy
(c) Oogamy
(d) Isogamy
Answer:
(b) Somatogamy

TN 11th Biology Important Questions State Board English Medium 2021-2022.

TN State Board 11th Biology Important Questions and Answers

TN State Board 11th Bio Botany Important Questions and Answers

• Chapter 1 Living World Important Questions
• Chapter 2 Plant Kingdom Important Questions
• Chapter 3 Vegetative Morphology Important Questions
• Chapter 4 Reproductive Morphology Important Questions
• Chapter 5 Taxonomy and Systematic Botany Important Questions
• Chapter 6 Cell: The Unit of Life Important Questions
• Chapter 7 Cell Cycle Important Questions
• Chapter 8 Biomolecules Important Questions
• Chapter 9 Tissue and Tissue System Important Questions
• Chapter 10 Secondary Growth Important Questions
• Chapter 11 Transport in Plants Important Questions
• Chapter 12 Mineral Nutrition Important Questions
• Chapter 13 Photosynthesis Important Questions
• Chapter 14 Respiration Important Questions
• Chapter 15 Plant Growth and Development Important Questions

TN State Board 11th Bio Zoology Important Questions and Answers

• Chapter 1 The Living World Important Questions
• Chapter 2 Kingdom Animalia Important Questions
• Chapter 3 Tissue Level of Organisation Important Questions
• Chapter 4 Organ and Organ Systems in Animals Important Questions
• Chapter 5 Digestion and Absorption Important Questions
• Chapter 6 Respiration Important Questions
• Chapter 7 Body Fluids and Circulation Important Questions
• Chapter 8 Excretion Important Questions
• Chapter 9 Locomotion and Movement Important Questions
• Chapter 10 Neural Control and Coordination Important Questions
• Chapter 11 Chemical Coordination and Integration Important Questions
• Chapter 12 Trends in Economic Zoology Important Questions

TN 11th Bio Zoology Important Questions State Board English Medium 2021-2022.

TN State Board 11th Bio Zoology Important Questions and Answers

• Chapter 1 The Living World Important Questions
• Chapter 2 Kingdom Animalia Important Questions
• Chapter 3 Tissue Level of Organisation Important Questions
• Chapter 4 Organ and Organ Systems in Animals Important Questions
• Chapter 5 Digestion and Absorption Important Questions
• Chapter 6 Respiration Important Questions
• Chapter 7 Body Fluids and Circulation Important Questions
• Chapter 8 Excretion Important Questions
• Chapter 9 Locomotion and Movement Important Questions
• Chapter 10 Neural Control and Coordination Important Questions
• Chapter 11 Chemical Coordination and Integration Important Questions
• Chapter 12 Trends in Economic Zoology Important Questions

TN 11th Bio Botany Important Questions State Board English Medium 2021-2022.

TN State Board 11th Bio Botany Important Questions and Answers

• Chapter 1 Living World Important Questions
• Chapter 2 Plant Kingdom Important Questions
• Chapter 3 Vegetative Morphology Important Questions
• Chapter 4 Reproductive Morphology Important Questions
• Chapter 5 Taxonomy and Systematic Botany Important Questions
• Chapter 6 Cell: The Unit of Life Important Questions
• Chapter 7 Cell Cycle Important Questions
• Chapter 8 Biomolecules Important Questions
• Chapter 9 Tissue and Tissue System Important Questions
• Chapter 10 Secondary Growth Important Questions
• Chapter 11 Transport in Plants Important Questions
• Chapter 12 Mineral Nutrition Important Questions
• Chapter 13 Photosynthesis Important Questions
• Chapter 14 Respiration Important Questions
• Chapter 15 Plant Growth and Development Important Questions

TN 12th Biology Important Questions State Board English Medium 2021-2022.

TN State Board 12th Biology Important Questions and Answers

TN State Board 12th Bio Botany Important Questions and Answers

• Chapter 1 Asexual and Sexual Reproduction in Plants Important Questions
• Chapter 2 Classical Genetics Important Questions
• Chapter 3 Chromosomal Basis of Inheritance Important Questions
• Chapter 4 Principles and Processes of Biotechnology Important Questions
• Chapter 5 Plant Tissue Culture Important Questions
• Chapter 6 Principles of Ecology Important Questions
• Chapter 7 Ecosystem Important Questions
• Chapter 8 Environmental Issues Important Questions
• Chapter 9 Plant Breeding Important Questions
• Chapter 10 Economically Useful Plants and Entrepreneurial Botany Important Questions

TN State Board 12th Bio Zoology Important Questions and Answers

• Chapter 1 Reproduction in Organisms Important Questions
• Chapter 2 Human Reproduction Important Questions
• Chapter 3 Reproductive Health Important Questions
• Chapter 4 Principles of Inheritance and Variation Important Questions
• Chapter 5 Molecular Genetics Important Questions
• Chapter 6 Evolution Important Questions
• Chapter 7 Human Health and Diseases Important Questions
• Chapter 8 Microbes in Human Welfare Important Questions
• Chapter 9 Applications of Biotechnology Important Questions
• Chapter 10 Organisms and Population Important Questions
• Chapter 11 Biodiversity and its Conservation Important Questions
• Chapter 12 Environmental Issues Important Questions

Students get through the TN Board 12th Chemistry Important Questions Chapter 1 Metallurgy which is useful for their exam preparation.

TN State Board 12th Chemistry Important Questions Chapter 1 Metallurgy

Question 1.
Name a few metals that occur natively.
Answer:
Silver, gold, platinum, copper occur in nature in significant amounts.

Question 2.
Distinguish between ore and minerals.
Answer:
Both minerals and ores are naturally occurring compounds of the metal. It is possible to extract metal in large quantities and in an easy manner from ore but it is not so in a mineral. All ores are minerals but all minerals are not ores.

Question 3.
What do you understand by the term “concentration of the ore”?
Answer:
The ore particles are associated with earthy impurities like sand, clay etc. These impurities have to be removed before it is subjected to extraction. The removal of impurities from the ore by specific methods is known as the concentration of the ore.

Question 4.
Write the name and formula of the common ores of aluminium, iron and copper.
Answer:

Question 5.
The names of a few ores are given. Write the composition of the ore. (i) Calamine, (ii) Zincite, (Hi) Galena, (iv) Cerrusite, (v) Cassiterite, (vi) Silver glance, (vii) Chloroargyrite.
Answer:
(i) Calamine: ore of Zn: ZnCO₃
(ii) Zincite : ore of Zn: ZnO
(Hi) Galena: ore of Pb: PbS
(iv) Cerrusite: ore of Pb: PbCO₃
(v) Cassiterite: ore of Sn: SnO₂
(vi) Silver glance: ore of Ag: Ag₂S
(vii) Chlorargyrite: ore of Ag: AgCl

Question 6.
Briefly give the principle involved in gravity separation of concentrating the ore.
Answer:
This method uses the difference in specific gravity between the ore particles and impurities (gangue). The crushed ore is treated with a rapidly flowing current of water. Lighter gangue particles are washed away, leaving behind heavier ore particles.

Question 7.
Why is the froth floatation process selected for the concentration of sulphide ores?
Answer:
The sulphide ore particles are preferentially wetted by oil, becomes lighter and thus rise to the surface along with the froth while the gangue particles are preferentially wetted by water, becomes heavier and settle down at the bottom of the tank. In this way, sulphide ore particles are separated and hence concentrated.

Question 8.
Name the chemicals used as frothing agents in the froth floatation process.
Answer:
Pine oil and eucalyptus oil are used as a frothing agent in the froth floatation process.

Question 9.
What is the role of depressant in the froth floatation process?
Answer:
The depressants help in the separation of two sulphide ores. For example, in the case of an ore containing PbS (galena) and ZnS (Zinc blende), the depressant is sodium cyanide (NaCN). It prevents ZnS from coming to the froth but allows PbS to come with froth in the froth floatation process ZnS forms a soluble complex with NaCN.

Question 10.
Explain the term leaching.
Answer:
It is a chemical separation of the ore and impurities. It involves the treatment of the ore with a suitable reagent to make it soluble while impurities remain insoluble. The insoluble impurities are separated by filtration.

Question 11.
Explain how, gold ore is concentrated by leaching, (or) How is leaching used to concentrate native ores of gold?
Answer:
The crushed ore of Au is leached with an aerated dilute solution of NaCN. Gold is converted into a soluble cyanide complex. The gangue, aluminosilicate remains insoluble.

Question 12.
What is cementation? Explain with an equation.
Answer:
Gold can be recovered by reacting the deoxygenated leached solution with zinc. In this process, the gold is reduced to its elemental state (zero oxidation state) and the process is called cementation.

Question 13.
What is the role of ammonia in leaching ores containing nickel or copper or cobalt?
Answer:
When a crushed ore containing nickel, copper and cobalt is treated with aqueous ammonia under suitable pressure, ammonia selectively leaches these metals by forming their soluble complexes viz. [Ni(NH₃)₆]²⁺, [Cu(NH₃)₄]²⁺, and [CO(NH₃)₅H₂O]³⁺ respectively from the ore leaving behind the gangue, iron (III) oxides/hydroxides and aluminosilicate.

Question 14.
Explain how bauxite ore is leached in the extraction of aluminium.
Answer:
The bauxite ore is treated with aqueous sodium hydroxide and heated to a temperature of around 470 – 520 K, at 35 atm. The aluminium dissolves forming a soluble complex, sodium meta aluminate leaving behind impurities.
Al₂O₃ (S) + 2NaOH (aq) + 3H₂O (l) → 2Na [Al(OH)₄] aq.
The hot solution is separated from its impurities and CO₂ gas is passed. Pure alumina gas precipitated
2Na [Al(OH)₄] (aq) + CO₂ (g) → Al₂O₃. H₂0 + 2 NaHCO₃ (aq)
The precipitate is washed and dried.

Question 15.
How is sulphide ores leached?
Answer:
The sulphide ores (ZnS, PbS) are treated with hot, aqueous sulphuric acid. The insoluble sulphide is converted to soluble sulphate and elemental sulphur which gets precipitated.
2ZnS (s) + 2H₂SO₄ (aq) + O₂ (g) → 2ZnSO₄ (aq) + 2S (s) + H₂O

Question 16.
Explain the principle involved in the magnetic separation of the ore with an example.
Answer:

This method is based on the difference in magnetic properties of the ore and the impurities. For example, tinstone, an ore of tin can be separated from its magnetic impurities (wolframite). The crushed ore is poured onto an electromagnetic separator consisting of a belt moving over two rollers of which one is magnetic. The magnetic part of the ore is attracted towards the magnet and falls as a heap close to the magnetic region while the non-magnetic part falls away.

Question 17.
Give chemical equations involved in the process of roasting.
Answer:
Roasting converts sulphide ores to their oxides.

It also removes volatile impurities like moisture and non-metals as their oxides.

Question 18.
Explain the term ‘Roasting’ in metallurgy.
Answer:
Roasting is a process in which sulphide ores are converted to oxide ores by heating the ore in excess of oxygen in a reverberatory furnace below the melting point of the metal.
eg: Galena when roasted gets converted to lead monoxide.
2PbS + 3O₂ → 2PbO + SO₂
During roasting volatile and non-metallic impurities are removed. The ore is rendered porous so that further steps in the extraction process becomes easy.

Question 19.
What is calcination? Explain with an example.
Answer:
Calcination is the process in which the concentrated ore is heated strongly in the absence of air. During this process, the water of crystallisation present in hydrated oxides escapes as moisture; This method is carried out in a limited supply of air. For example, calcination of the carbonate ore, carbon dioxide example is expelled.

Question 20.
Distinguish between calcination and roasting.
Answer:

1. Both processes are used to convert ores into metallic oxides. During roasting sulphide ores are converted to oxides and during calcination carbonate ores are converted to oxides.
2. Roasting is carried out by heating the ore with excess oxygen below the melting point of the ore whereas calcination is done by heating the ore in a limited supply of oxygen.
3. During roasting volatile impurities are removed and non-metallic impurities escape as their oxides. During calcination, the water of crystallisation escapes.
4. Both processes render the ore porous which makes further steps of the extraction process easiest.

Question 21.
Write chemical equations involved in the calcination process?
Answer:
Calcination is the process that involves the conversion of carbonate ores to oxides.

The water of crystallisation of hydrated salts escapes as water vapour.

Question 22.
Give a brief account of the reduction of metal oxides to metals.
Answer:

1. Metal oxides can be reduced to metals by using a suitable reducing agent. The choice of the reducing agent depends on the nature of the metal. The reducing agents used commonly are carbon, carbon monoxide, hydrogen and reactive metals like sodium.
2. Carbon is used as a reducing agent in the reduction of oxide ores such as ZnO, Mn₃O₄ and Cr₂O₃. The ore and coke are heated strongly in a blast furnace.
   
3. Carbon monoxide is used to reduce ferric oxide in the extraction of iron.
   Fe₂O₃ (s) + 3CO (g) → 2Fe (s) + 3CO₂ (g) ↑
4. Gaseous hydrogen is used to reduce oxides of less electropositive metals (Fe, Pb, Cu) than hydrogen.
   Ag₂O + H₂ → 2Ag + H₂O
   Fe₃O₄ + 4H₂ → 3Fe + 4H₂O
5. Aluminium is used to reduce metal oxides like Cr₂O₃.
   
   Active metals such as sodium, potassium and calcium are also used as reducing agents.
   B₂O₃ + 6Na → 2B + 3Na₂O
   Rb₂O₃ + 3Mg → 2Rb + 3MgO

Question 23.
What do you understand by the terms (i) Flux, (ii) Slag? Explain with examples.
Answer:

1. Flux is a chemical substance that is added to the concentrated ore, to remove impurities present. The impurities combine with the flux and form a fusible mass slag.
2. Acidic impurities are removed by using a basic flux and basic impurities are removed by adding acidic fluxes.
3. Silicon dioxide is an acidic flux and limestone (CaO) is a basic flux.
4. CaO(s), the basic flux removes the gange silicon dioxide (SiO₂), as calcium silicate (slag) in the extraction of iron.
   

Slag: Slag is a compound formed when flux and gangue can combine with each other. The slag is a feasible mass, which removes, the impurities in the ore. In the extraction of iron, FeO is added as a flux to remove the gangue (SiO₂) as ferrous silicate (slag).

Question 24.
Give chemical equations involved in the extraction of copper from copper pyrites.
Answer:

1. Smelting of the concentrated ore:
   Cu₂S and FeS formed in equation (1) is called mattle.
2. The remaining Cu₂S is further oxidised to cuprous oxide, which is subsequently converted to metallic copper.
   Cu₂S + 3O₂ → 2Cu₂S + 2SO₂
   2Cu₂O + Cu₂S → 6Cu + SO₂

Question 25.
Complete and balance the following equations.
Answer:

Question 26.
Briefly outline the thermodynamic principle involved in metallurgy.
Answer:
For any process, Gibb’s free energy change ΔG should be negative, i.e.,
ΔG = ΔH – TΔS should be negative where ΔH and ΔS are enthalpy and entropy changes respectively. The extraction of the metals from their oxides is carried out by using different reducing agents. A suitable reducing agent is chosen based on thermodynamics.
Let us consider the reduction of metallic oxide by carbon.

Thermodynamically, the reduction of metal oxide (equation -1), with a given reducing agent (equation -2) can occur if the free energy change for the coupled reaction is negative. Hence the reducing agent in chosen in such a way to produce a large negative value for the coupled reactions.

Question 27.
What is the Ellingham diagram? Explain.
Answer:
Ellingham’s diagram is used to obtain the ΔG° values at various temperatures for the reduction of metal oxides by treating reduction as an equilibrium process.
The diagram is made by plotting temperature in the x-axis and the standard free energy of formation (ΔG°) of the metal oxide in the ‘y ’ axis. The resultant plot is a straight line with ΔS as slope and ΔH as ‘y’ intercept. The graphical representation of the variation of standard free energy of formation of various metal oxides with temperature is known as the Ellingham diagram.

Question 28.
Briefly explain the salient features of the Ellingham diagram.
Answer:
(i) Ellingham diagram consists of plots that represent the variation of standard free energy of formation of metal oxides versus temperature.
(ii) These plots help is in predicting the feasibility of thermal reduction of ore. Consider the formation of metal oxide.
2xM (s) + O₂ (g) → 2MxO (s)
In this reaction, there is a decrease in the value of ΔS° as M.rO is a solid and 02 is a gas. i.e., ΔS° is negative. Thus, if the temperature is increased, TΔS° becomes more negative. As in the equation ΔG° = ΔH° – TΔS°
TΔS° is substracted, therefore ΔG° becomes less negative i.e., ΔG° is likely to increase with temperature and this trend is confirmed from the curves of metal oxides.
The following observations are made from the curves.
(a) The slope of the curves of formation of metal oxides is positive because ΔG° becomes less negative and increases with temperature.
(b) Each curve is a straight line except when some change takes place in phase. The temperature at which such a change occur is indicated by an increase in slope on the positive side.
(c) In the case of CO, ΔG° decreases as ΔS° increases. This is indicated by the downward trend.
(d) Any metal oxide with lower ΔG° is more stable than a metal oxide with higher ΔG°. This implies that the metal oxide placed higher in the diagram can be reduced by the metal lower in the diagram.

Question 29.
Mention the limitations of the Ellingham diagram.
Answer:

1. Ellingham diagram is constructed based only on thermodynamic considerations. It gives information about the thermodynamic feasibility of a reaction. It does not tell anything about the rate of the reaction. Moreover, it does not give any idea about the possibility of other reactions that might be taking place.
2. The interpretation of ΔG is based on the assumption that the reactants are in equilibrium with the product which is not always true.

Question 30.
Based on the Ellingham diagram explain.
Answer:

1. Aluminium can be used as a reducing agent for the reduction of chromic oxide.
   In the Ellignhem diagram, the formation of chromium oxide lies above that of the aluminium, meaning that Al₂O₃ is more stable than Cr₂O₃. Hence aluminium can be used as a reducing agent for the reduction of chromic oxide.
2. Aluminium cannot be use4 to reduce MgO or CaO.
   The formation of MgO or CaO lies below that, that of aluminium. Hence, it cannot be used to reduce oxides of Mg or Ca.

Question 31.
Why is the reduction of a metal oxide easier if the metal is in the liquid state at the temperature of reduction?
[OR]
Account for the fact that the reduction of a metal oxide is easier if the metal is formed in the liquid state at the temperature of reduction.
Answer:
Entropy is higher when the metal is in the liquid state than when it is in the solid-state. Therefore, the value of entropy change (ΔS°) of the reduction process is more positive, when the metal is formed in the liquid state. The value of TΔS° increases and that of ΔH° remains constant, the value of ΔG° becomes more negative and hence reduction becomes easier.

Question 32.
The choice of a reducing agent in a particular reduction depends on the thermodynamic factor. How far do you agree with this statement?
Answer:
Support your opinion with two examples.
From the Ellingham diagram, it is evident that any metal oxide with a lower AG° value is more stable than the metal oxide with a higher AG° value. This implies that the metal oxide placed lower in the diagram cannot be reduced by a metal involved in the formation of oxide placed higher in the diagram. However, the reverse can readily take place.
Thus, Al₂O₃ cannot be reduced by Cr however Cr₂O₃ can be reduced by Al.
At temperature 1733K, AG° formation of Al₂O₃ and Cr₂O₃ is given below.

The reduction of Al₂O₃ by Cr may be obtained by subtracting equation (i) and (ii).

ΔG° = 400 kJ mol-1 This reaction is thermodynamically not feasible since ΔG° has a positive value. But the reverse reaction is possible as it has a negative ΔG° value. Similarly, both aluminium and zinc can reduce FeO to Fe, but Fe cannot reduce Al₃O₂ Or ZnO.

Question 33.
Based on the Ellingham diagram given below predict a suitable reducing agent for the reduction of Cu₂O.
Answer:

It is seen in the diagram that the Cu₂0 curve lies almost at the top while the lines sharing the formation of CO₂ from C, and the formation of CO from carbon lie much below it. So it is easy to reduce Cu₂O to the metal by heating it with coke at temperatures after 500 – 600 K.
Cu₂O + C → 2Cu + CO

Question 34.
Show by using the Ellingham diagram given below to predict the possible temperature at which ZnO is reduced to Zn by carbon.
Answer:

Ellingham diagram reveals that the lines involving the formation of ZnO and carbon monoxide cross each other at about 1270 K. There is a sudden increase in the value of ΔG° for the formation of ZnO above 1180°C. This is due to the fact that zinc begins to boil at this temperature. Above, 1270 K, ΔG° for the reaction.

is considered negative and thus ZnO is reduced by coke.

Question 35.
Out of carbon and carbon monoxide which is a better reducing agent for ZnO?
Answer:
From Ellingham’s diagram, it is clear that the free energy of formation of CO from C is lower at a temperature above 1120 K while that of CO₂ from carbon is lower above 1323K than that of free energy of formation of ZnO. However, the free energy of the formation of CO₂ from CO is always higher than that of ZnO. Hence, C is a better reducing agent of ZnO.

Question 36.
Explain why is the extraction of copper from pyrites difficult than that from its oxide ore through reduction.
Answer:
The standard free energy formation (ΔG°) for Cu₂S is more negative than those of CS₂ and H₂S. Therefore neither carbon nor hydrogen can reduce Cu₂S to copper. But the standard free energy of formation of Cu₂0 (ΔG°) is less negative than that of CO and hence carbon can readily reduce Cu₂O to Cu.
Alternatively,
ΔG° / T line for CO has a negative slope and there is no compound CS analogous to CO with a steep negative ΔG°/T line. Thus, carbon is a good reducing agent for oxides and not for sulphides. Therefore sulphide ores are normally roasted in air to form oxides before reducing than with carbon.

Question 37.
Given the following ores indicate which of them Can be concentrated by magnetic separation method, (i) Bauxite, (ii) Kaolinite, (iii) Haematite, (iv) siderite, (v) iron pyrites, (vi) copper pyrites, (vii) galena, (viii) cassiterite, (ix) horn silver, (x) zincite, (xi) magnetite.
Answer:
Ores that are magnetic in nature can be separated from non-magnetic gangue particles by magnetic separation ores of iron such as Haematite (Fe₂O₃), Magnetite (Fe₃O₂), Siderite (FeCO₃) and Iron pyrites (FeS₂) being magnetic can be separated by magnetic separation.

Question 38.
Explain the principles involved in each of the following processes of refining metals. (i) Distillation, (ii) Liquation, (iii) Electrolyte refining, (iv) zone refining, (v) vapour phase method.
Answer:

1. Distillation: This method is used for the purification of volatile metals like zinc, mercury, cadmium etc. The impure metal is heated in a retort and the vapours are condensed in separate receivers. The pure metal distils leaving behind the non-volatile having higher boiling point) impurities in the retort.
2. Liquation: This method is used for the purification of metals in which the melting points of metals are lower than these of the impurities. The crude metal is heated in an inert atmosphere on a sloping hearth of a reverberatory furnace when the metal flows down into the receiver leaving behind infusible impurities on the hearth. Metals like tin and lead one purified by this method.
3. Electrolyte refining:
   Electrolytic refining is a process of purification of an impure metal by electrolysis. The impure metal is used as an anode and a pure metal is used as a cathode. The electrolyte is a suitable aqueous solution of the salt of the metal. During electrolysis, the metal dissolves at the anode, migrates to the cathode and gets deposited as a pure metal, eg: Electrolytic refining of silver:
   Cathode: Pure silver Anode: Impure silver rods Electrolyte: Acidified aqueous solution of silver nitrate.
   When a current is passed through the electrodes the following reactions will take place.
   Reaction at anode 2Ag (s) → Ag⁺ (aq) + e^–
   Reaction at cathode Ag⁺ (aq) + e^– → Ag(s)
   During electrolysis, at the anode, the silver atoms lose electrons and enter the solution. The positively charged silver cations migrate towards the cathode and get discharged by gaining electrons and deposited on the cathode. Other metals such as copper, zinc etc., can also be refined by this process in a similar manner.
4. Zone refining: This method is based on the principles of fractional crystallisation. When an impure metal is melted and allowed to solidify, the impurities will prefer to be in the molten region, i.e., impurities are more soluble in the melt than in the solid-state metal. In this process, the impure metal is taken in the form of a rod. One end of the rod is heated using a mobile induction heater which results in the melting of the metal on that portion of the rod. When the heater is slowly moved to the other end the pure metal crystallises while the impurities will move on to the adjacent molten zone formed due to the movement of the heater. As the heater moves further away, the molten zone containing impurities also moves along with it. The process is repeated several times by moving the heater in the same direction again and again to achieve the desired purity level. This process is carried out in an inert gas atmosphere to prevent the oxidation of metals. Elements such as germanium (Ge), silicon (Si) and gallium (Ga) that are used as semiconductor are refined using this process.
   (v) Vapour phase method:
   The basic requirement is that the metal, when treated with a suitable reagent form a volatile compound which as decomposition gives the pure metal. eg: Nickel forms a volatile nickel carbonyl on heating with carbon monoxide, which on decomposition gives pure nickel.

Question 39.
Explain how zinc is purified by electrolytic refining.
Answer:
The impure zinc is made the anode while the cathode consists of pure sheets of zinc. The electrolyte is an acidified (H₂SO₄) solution of zinc sulphate (ZnSO₄). On passing electric current pure zinc deposits on the cathode.

Question 40.
State the role of silver in the metallurgy of copper.
Answer:
During roasting, copper pyrites are converted to a mixture of FeO and Cu₂O.

To remove FeO (basic impurity) an acidic flux, SiO₂ is added during smelting. FeO combines with SiO₂ to form ferrous silicate (FeSiO₃) as slag and floats over the molten matter and hence can be easily removed.

Question 41.
What is the role of graphite in the electrometallurgy of aluminium?
Answer:
In the electrometallurgy of aluminium, a fused mixture of alumina, cryolite and fluorspar (CaF₂) is electrolysed using graphite as anode and graphite lined iron as a cathode. During electrolysis, Al is liberated at the cathode while CO and CO₂ one liberated at the anode.
At Cathode: Al⁺³ (melt) → Al (l)
At anode: C + O^-2 (melt) → CO + 2e^–
C + 2O^-2 (melt) → CO₂ + 4e^–
Instead of graphite, some metal is used as an anode, then O₂ liberated will not only oxidise the metal of the electrode but would also convert the same Al liberated at the cathode back to Al₂O₃.
Since graphite is much cheaper than any metal, it is used as a cathode. Thus the role of graphite in the electrometallurgy of Al is to prevent the liberation of 02 at the anode. Which may otherwise convert Al to Al₂O₃.

Question 42.
Mention the application of the following metals, (i) Al, (ii) Cu, (iii) Fe, (iv) Au.
Answer:
Al: Aluminium is the most abundant metal and is a good conductor of electricity and heat. It also resists corrosion. The following are some of its applications.

1. Many heat exchangers/sinks and our day to day cooking vessels are made of aluminium.
2. It is used as wraps (aluminium foils) and is used in packing materials for food items.
3. Aluminium is not very strong, However, its alloys with copper, manganese, magnesium and silicon are lightweight and strong and they are used in the design of aeroplanes and other forms of transport.
4. As aluminium shows high resistance to corrosion, it is used in the design of chemical reactors, medical equipment, refrigeration units and gas pipelines.
5. Aluminium is a good electrical conductor and cheap, hence used in electrical overhead electric cables with a steel core for strength.

Cu:

1. Copper is used for making coins and ornaments along with gold and other metals.
2. Copper and its alloys are used for making wires, water pipes and other electrical parts.

Fe:

1. Iron and its alloys are used everywhere including bridges, electricity pylons, bicycle chains, cutting tools and rifle barrels.
2. Cast iron is used to make pipes, valves and pumps stoves etc…
3. Magnets can be made of iron and its alloys and compounds.
4. An important alloy of iron is stainless steel, and it is resistant to corrosion. It is used in architecture, bearings, cutlery, surgical instruments and jewellery. Nickel steel is used for making cables, automobiles and aeroplane parts. Chrome steels are used for manufacturing cutting tools and crushing machines.

Au:

1. Gold is used for coinage and has been used as the standard for monetary systems in some countries.
2. It is used extensively in jewellery in its alloy form with copper. It is also used in electroplating to cover other metals with a thin layer of gold which are used in watches, artificial limb joints, cheap jewellery, dental fillings and electrical connectors.
3. Gold nanoparticles are also used for increasing the efficiency of solar cells and also used as catalysts.

TN 12th Chemistry Important Questions State Board English Medium 2021-2022.

TN State Board 12th Chemistry Important Questions and Answers

• Chapter 1 Metallurgy Important Questions
• Chapter 2 p-Block Elements – I Important Questions
• Chapter 3 p-Block Elements – II Important Questions
• Chapter 4 Transition and Inner Transition Elements Important Questions
• Chapter 5 Coordination Chemistry Important Questions
• Chapter 6 Solid State Important Questions
• Chapter 7 Chemical Kinetics Important Questions
• Chapter 8 Ionic Equilibrium Important Questions
• Chapter 9 Electro Chemistry Important Questions
• Chapter 10 Surface Chemistry Important Questions
• Chapter 11 Hydroxy Compounds and Ethers Important Questions
• Chapter 12 Carbonyl Compounds and Carboxylic Acids Important Questions
• Chapter 13 Organic Nitrogen Compounds Important Questions
• Chapter 14 Biomolecules Important Questions
• Chapter 15 Chemistry in Everyday Life Important Questions

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 12 Environmental Issues which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 12 Environmental Issues

Very short answer questions

Question 1.
Define Pollution.
Answer:
Pollution is defined as any undesirable change in the physical, chemical, and biological characteristics of an environment.

Question 2.
What are pollutants?
Answer:
Pollutants are the agents which cause pollution.

Question 3.
What are the different basic groups of pollutants?
Answer:
The pollutants are classified into two major groups namely Non-degradable and degradable pollutants.

Question 4.
Name the main sources of carbon monoxide pollution.
Answer:
The main sources of carbon monoxide pollution include Automobile exhausts, fumes from factories and the burning of firewood.

Question 5.
Define SMOG.
Answer:
SMOG is defined as a type of air pollution caused by tiny particles in the air.

Question 6.
Mention any two cost-effective treatments of air pollution?
Answer:
The cost-effective treatment of air pollution includes:

1. Growing indoor plants and
2. Using high-performance biofilters.

Question 7.
Explain Air Quality Index (AQI).
Answer:
Air Quality Index is the number used by Government agencies to communicate to the public how polluted the air is at a given time.

Question 8.
Name any two examples of the non-point sources of pollutants.
Answer:

1. Agriculture chemical run-off.
2. Dumping of plastics in water bodies.

Question 9.
Define Noise pollution.
Answer:
Noise pollution is defined as the sound that is unwanted and undesirable or can disrupt one’s quality of life.

Question 10.
Name the chemicals present in mosquito repellents.
Answer:
The chemicals present in mosquito repellents are:

1. DEET (n-n-diethylenetatoluamide)
2. Alletrin

Question 11.
Define Biomagnification.
Answer:
Biomagnification is the process in which a non-degradable substance, that enters die – food chain does not get metabolized and instead gets transferred up the tropic levels of the food chain with the magnified level of that substance.

Question 12.
What is ‘4R’?
Answer:
‘4R’ means Refuse, Reduce, Reuse and Recycle. These are the mantra for remedy II for the plastic waste problem.

Short answer questions

Question 1.
What are plastics? Explain their sources.
Answer:
Plastics are low molecular weight organic polymers, that are not degradable in the natural environment.
The main sources of this plastic include:

1. The packaging material used in supermarkets.
2. Packing material in retail outlets.
3. Manufacturing industries.
4. Households, hotels, hospitals, and restaurants, and transport companies.
5. In municipal solid waste, plastic waste constitutes a major part.

Question 2.
Recycling and disposal of e-waste involve significant risk – Justify.
Answer:
The recycling and disposal of e-waste may involve risks to the health of workers and communities in developed countries.

1. Great care must be taken to avoid unsafe exposure in recycling operations.
2. The leading of materials like heavy metals from landfills and incinerator ashes may cause health problems to humans and animals.

Question 3.
How does water pollution affect on the ecosystem?
Answer:
Water pollution generally affects the aquatic ecosystems in the following ways:

1. It affects existing riches and habitats.
2. It affects the survival of organisms.
3. In certain cases, soil fertility is affected, leading to the state of uninhabitable.
4. It results in Eutrophication.

Question 4.
What are three sources of water pollution?
Answer:
The three sources of water pollution are:

1. Municipal waste
2. Industrial waste
3. Agricultural waste

Question 5.
Water pollution disrupts the nature of food chains as well as food webs – Justify.
Answer:

1. Pollutants such as lead and cadmium are taken up by primary consumers, where they can be lethal or get accumulated.
2. When these animals are consumed by secondary consumers, their pollutants are get enhanced by a process called biomagnification.
3. The food chain may get disrupted at any trophic level due to the magnification and accumulation of these chemicals.

Question 6.
Explain the Government Act and regulations to prevent water pollution.
Answer:

1. Water Act, 1974, section 17- 40 – Prohibits the pollution of a stream or well by disposal of polluting matter.
2. The Central / State pollution control Boards – They have the power to advise the central / state governments on various matters concerned with the prevention and. control of pollution of water.
3. The Ministry of Environment, forest and climate change (MoEFCC) is the nodal agency of the central government for planning, promotion, coordination, and overseeing the implementation of India’s environmental and forestry policies and programs.

Question 7.
How do you control ozone layer depletion?
Answer:

1. Phase down or ban the use of CFCs (CFC-free refrigerants).
2. The usage of chemicals such as halons and halocarbons ought to be minimized.
3. Creating awareness about ozone-depleting agents.

Long answer questions

Question 1.
Give an account of medical waste.
Answer:
Medical waste refers to any waste that contains infectious material generated by hospitals, medical research centers, laboratories, pharmaceutical companies, and veterinary clinics.
Medical’wastes constitute fluid like blood, urine, body parts, and other contaminants. They also include used syringes and needles, culture dishes, glasswares, bandages gloves, scalpels, swabs, and tissues.
Hie social and legal responsibilities of – people working in health care centers are the safe disposal of medical waste.
The disposal methods include incineration, chemical disinfection, autoclaving, encapsulation microwave irradiation. Landfill and burying inside premises as per norms are the final disposal of these wastes.

Question 2.
Describe the prevention methods of water pollution.
Answer:
The followings are the prevention strategies of water pollution:

1. Regulate or control pollutant discharge at the point of generation.
2. Treatment of wastewater by scientific methods before discharge into municipal treatment sources.
3. Setting up of Sewage Treatment Plants (STP) and Effluent Treatment Plants (ETP) where ever needed.
4. Regulate or restrict the use of chemical fertilizers and pesticides in agriculture. Create public awareness and involve people in the action plan.

Question 3.
Enumerate the effects of noise pollution.
Answer:
A link between noise and the health of humans and other organisms was established by USEPA (the United States Environmental Protection Agency). The noise pollution effects are:

1. It causes increased stress and tension nervousness, irritability anxiety depression, and panic attacks.
2. It also causes peptic ulcers, severe headaches, memory loss.
3. Noise pollution from offshore activities and poor activities affects marine animals.
4. Noise from firecrackers frightens animals and birds.
5. In humans, heart disease, high blood pressure, stress-related illness, sleep disruption, hearing loss, and productivity loss are some of the problems related to noise pollution.

Question 4.
Explain the causes and effects of ozone layer depletion.
Answer:
Causes:

1. Anthropogenic activities mainly cause ozone layer depletion.
2. Chlorofluorocarbons (CFCs) is the main cause of ozone layer depletion by releasing excess chlorine and bromine. Other ozone-depleting substances are hydrobromic fluorocarbons and methyl bromide.

Effects:

1. It allows UY rays to penetrate into the atmosphere, resulting in premature aging of skin and wrinkling of the skin.
2. It may cause suppression of the immune system.
3. It causes skin cancer (melanoma) and chronic effects leading to eye damage.
4. The free radicals and reactive oxygen and photons can damage DNA itself.

Choose the correct answers:

1. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(ii); (q)-0); (r)-(iv); (s)-(iii)
(c) (p)-(iii); (q)-(iv); (r)-(ii);(s)-(i)
(d) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

3. Match the following:

(a) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
(d) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
Answer:
(a) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)

4. Match the following:

(a) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

5. Medical waste is classified under:
(a) Solid waste
(b) Organic waste
(c) Hazardous waste
(d) Chemical waste
Answer:
(c) Hazardous waste

6. Which of the following is an anaerobic ‘ process?
(a) Vermicomposting
(b) Biogas generation
(c) Segregation
(d) Nitrification
Answer:
(b) Biogas generation

7. How much garbage is collected per day from Chennai city?
(a) 5400 MT
(b) 4800 MT
(c) 2400 MT
(d) 6800 MT
Answer:
(a) 5400 MT

8. The method not used in the physical methods of waste treatment.
(a) Flotation
(b) Chlorination
(c) Sedimentation
(d) Filteration
Answer:
(b) Chlorination

9. Choose the odd man out:
(a) Nammalvar
(b) Sultan Md. Ismail
(c) Thiagarajan
(d) Jadav Payeng
Answer:
(c) Thiagarajan

10. Identify the odd one:
(a) Food waste
(b) Paper waste
(c) Plastic waste
(d) Organic waste
Answer:
(c) Plastic waste

11. Choose the odd one:
(a) Dilute and disperse
(b) Segregation and treatment
(c) Delay and decay
(d) Concentrate and confine
Answer:
(a) Dilute and disperse

12. Find out the odd one:
(a) Bandages
(b) Sealpels
(c) Glasswares
(d) Swabs and tissues
Answer:
(b) Sealpels

13. Which of the following is a correct pair?

Answer:
(c)

14. Choose the incorrect pair:

Answer:
(d)

15. Find out the correct pair:

Answer:
(a)

16. Indicate the incorrect pair:

Answer:
(c)

17. Assertion: Organic farming creates an eco-friendly pollution-free environment.
Reason: In organic farming, only natural and organic agro-inputs are used.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

18. Assertion: DDT concentration is more in fish-eating birds than the actual concentration of the aquatic system.
Reason: This is due to a phenomenon called Biomagnification.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

19. Assertion: The permissible limit of noise in commercial areas is 65 decibels during the day and 45 decibels during the night.
Reason: The threshold pain of noise pollution is 120 decibels.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason is correct.
(e) Both Assertion and Reason are not correct.
Answer:
(d) Assertion is not correct, Reason is correct.

20. Assertion: Acid rain is caused by Sulphur dioxide and nitric oxide.
Reason: During rain, the precipitation contains acidic components such as sulphuric acid or nitric acid.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is correct, Reason is not correct.
(d) Assertion is not correct, Reason correct.
(e) Both Assertion and Reason are not correct.
Answer:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

21. Which of the following statement is correct?
(a) Thinning of the stratospheric ozone layer is caused by all GHGs.
(b) Thinning of the stratospheric ozone layer is caused by CO₂ emission.
(c) Thinning of the stratospheric ozone layer is caused by Cf Cs.
(d) None of the above.
Answer:
(a) Thinning of the stratospheric ozone layer is caused by all GHGs.

22. Choose the incorrect statement:
(a) Trees are the best remedy for urban particulate matter.
(b) Forests act as sink for CO₂.
(c) Forests act as lungs of planet.
(d) All the above statements are not correct.
Answer:
(d) All the above statements are not correct.

23. Indicate the correct statement:
(a) Noise pollution can cause severe stomach ache.
(b) The threshold pain of noise pollution is about 120 decibels.
(c) Marine animals are not affected by noise pollution.
(d) None of the above.
Answer:
(b) The threshold pain of noise pollution is about 120 decibels.

24. Choose the incorrect statement:
(a) Limit generation is the most important consideration in managing radioactive wastes.
(b) Dilution and dispersion are adopted for wastes having high radioactivity.
(c) Much of the radioactivity in nuclear reactors and accelerator is very short-lived.
(d) Concentrate and confine process is another method of radioactive material disposal.
Answer:
(b) Dilution and dispersion are adopted for wastes having high radioactivity.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 11 Biodiversity and its Conservation which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 11 Biodiversity and its Conservation

Very short answer questions

Question 1.
Define Biodiversity.
Answer:
Biodiversity is defined as the assemblage of different life forms on Earth.

Question 2.
What is genetic diversity?
Answer:
Genetic diversity refers to the difference in genetic makeup between distinct species, within a single species, and between different populations.

Question 3.
Name any two ecosystem services.
Answer:

1. Providing food to many organisms.
2. Ecotourism.

Question 4.
What is the indicator of the health of an ecosystem?
Answer:
Endemism is the crucial indicator of the health of an ecosystem.

Question 5.
In South-East Asia, the dwindling of fruit bats is followed by a reduction in local fruit production. Why?
Answer:
The local fruit production in south-East Asia has got affected as the bats are found to be the pollinators of fruit trees.

Question 6.
Name any two animals found in the Deccan peninsula.
Answer:

1. Sambhar
2. Elephant

Question 7.
What are alien species?
Answer:
Alien species are organisms often introduced in a habitat unintentionally or deliberately for commercial purposes or a biological control agent and other uses.

Question 8.
What is the main effect of climate change?
Answer:
Climate change increases land and ocean temperature changes precipitation patterns and raises the sea level.

Question 9.
Name any two alien species introduced in India.
Answer:
The alien species introduced in India include Tilapia, Oreochromis mossambicus and Amazon sailfin catfish.

Question 10.
Define Endangered Species.
Answer:
Endangered species are defined as species that are very likely to be extinct in near future.

Question 11.
Expand IUCN.
Answer:
IUCN means International Union for Conservation of Nature.

Question 12.
Name any two national tiger reserves.
Answer:

1. Jim Corbett National park.
2. Kalakkad – Mundamthurai tiger reserve.

Short answer questions

Question 1.
What are sacred groves?
Answer:
Sacred groves of sacred woods are any assemblages of trees that are of special importance to a particular religion or culture. Sacred groves are seen in various cultures throughout the world. It is considered as one of the means of in situ conservation of plants and their associated organisms.

Question 2.
What are the advantages of gene banks? Gene banks are a type of biorepository, which collect and store genetic materials. The advantages of gene banks are as follows.
Answer:

1. The seeds of different genetic strains of commercially important plants can be stored for long periods in the seed bank.
2. Using the cryopreservation technique, the gametes of threatened species can be preserved in viable and fertile conditions.
3. Endangered species can be revived.

Question 3.
Write briefly about the principles of the Stockholm Declaration, 1972.
Answer:
The Stockholm convention in 1972 declared that the natural resources of Earth such as air, water, land, flora, and fauna of the natural ecosystems must be protected for the benefit of present and future generations. This should be done through careful planning, appropriate management, and judicial execution.

Question 4.
Name any three National parks in Tamil Nadu, their year, and place of establishment.
Answer:

Question 5.
List out any three important roles of IUCN.
Answer:

1. It influences, assists and encourages societies in the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable.
2. It influences Governments and industries through partnerships by providing information and advice.
3. It helps in the implementation of several international conventions on nature conservation and biodiversity.

Question 6.
Explain Coextinction with an example.
Answer:
Coextinction of a species is the loss of a species as a consequence of the extinction of another species.
Eg: Orchid bees and forest trees by cross-pollination. When the bees become extinct, the cross-pollination will not take place in forest trees and tree populations may also slowly become extinct.

Long answer questions

Question 1.
The richness of biodiversity in tropics is more. Justify.
Answer:
The reasons for the richness of biodiversity in the tropics are:

1. The warm tropical region on either side of the equator provides congenial habitat for living organisms.
2. Environmental conditions in the tropics are conducive for speciation as well as for supporting both variety and number of organisms.
3. The temperature in the tropic ranges between 25°C and 35°C, which are ideal for most of the metabolic activities of organisms.
4. The average rainfall is more than 200 mm per year, which is sufficient to support the whole ecosystem.
5. Rich resource and nutrient availability to support the functions of the ecosystem.
6. Climate, seasons, temperature, humidity, photoperiod etc., are more or less stable and encourage both variety and number.

Question 2.
List out the Biogeographical regions of India with their fauna.
Answer:

Question 3.
Pollutants and pollution are a major cause for biodiversity loss – Justify.
Answer:

1. The excessive use of fertilizers, pesticides, and heavy metals has polluted the land, ground, and surface water bodies.
2. There is a decline in the population of fish-eating birds and falcons due to pesticide biomagnification, which results in high concentrations of such pesticides in higher tropic levels like fishes.
3. Eutrophication of water bodies has resulted from the runoff from fertilizer-rich fields.
4. Metal contamination like mercury arsenic, cadmium, and chromium have to lead to the depletion of biotic resources in vulnerable ecosystems.
5. The veterinary medicine, Diclofenac used for the thinning of eggshells is said to be responsible for the death of the vulture population.

Question 4.
Explain the species-area relationship with the help of a diagram?
Answer:
The relationship between species richness and area for a wide variety of taxa (plants, birds, bats, freshwater fishes) will be a rectangular hyperbola in an arithmetic graph.
On a logarithmic scale, the relationship is a straight line described by the equation:
Log S = Log C + Z log A
where
S = Species richness
A = Area
Z = Slope of the line
C = Y-intercept .

Generally the regression coefficients or the slope value of the curve, Z has a value of 0.1- 0.2 regardless of taxonomic group or region. If the area is more like the entire continent, the curve will be steeper, the Z value being 0.6 – 1.2

Choose the correct answers:

1. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(ivj; (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(c) (p)-(ii); (q)-(i); (r)-(ivj; (s)-(iii)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)~(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

3. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)

4. Match the following:


(a) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(a) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

5. Sunda lands include:
(a) Himalaya
(b) Nicobar islands
(c) Andaman
(d) Srilanka
Answer:
(b) Nicobar islands

6. The year of establishment of Mudumalai NP is:
(a) 1976
(b) 1980
(c) 1990
(d) 1989
Answer:
(c) 1990

7. Biosphere reserve in India includes:
(a) Gulf of Mannar
(b) Madras Crocodile Bank
(c) Guindy National park
(d) National tiger project
Answer:
(a) Gulf of Mannar

8. The UN Earth summit, which defined Biodiversity, was held in the year:
(a) 1990
(b) 1992
(c) 1982
(d) 1996
Answer:
(b) 1992

9. Choose the odd man out:
(a) Walter Rosen
(b) Alexander Rom Humboldt
(c) Charles Darwin
(d) Edward Wilson
Answer:
(c) Charles Darwin

10. Find out the odd one:
(a) Oryza sativa
(b) mango
(c) wheat
(d) Rouwolfia vomitaria
Answer:
(d) Rouwolfia vomitaria

11. Indicate the odd one out:
(a) the Western Ghats
(b) Gulf of Mannar
(c) the Himalayas
(d) Gangetic plain
Answer:
(b) Gulf of Mannar

12. Choose the odd one out:
(a) Habitat lose
(b) Pollution
(c) Population control
(d) Overexploitation
Answer:
(c) Population control

13. Which of the following is the correct pair?

Answer:
(d)

14. Choose the incorrect pair:

Answer:
(b)

15. Find out the correct pair:

Answer:
(a)

16. Which of the following is an incorrect pair?

Answer:
(d)

17. Assertion and reason:
Assertion: Biodiversity is very important and worthy to protection.
Reason: Because it provides sustainable benefits for the present as well as future generations.
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.
(b) Both assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is correct, reason is not correct.
(d) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.

18. Assertion: Gene bank is a type of biorepository of genetic materials.
Reason: The genetic materials can be retrieved to revive endangered/threatened species.
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.
(b) Both assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is correct, reason is not correct.
(d) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.

19. Assertion: Biodiversity supplies a large number of goods and services that sustain human life.
Reason: It supplies food, fuel, and building materials.
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.
(b) Both assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is correct, reason is not correct.
(d) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(b) Both assertion and reason are correct, reason is not the correct explanation of assertion.

20. Assertion: Arignar Anna Zoological Park at Vandalur is the place of in-situ conservation of animals.
Reason: The Zoo has many attractive features like a Butterfly park, Aviary, Lion and deer safari, forest museum, etc.
(a) Both assertion and reason are correct, reason is the correct explanation of assertion.
(b) Both assertion and reason are correct, reason is not the correct explanation of assertion.
(c) Assertion is correct, reason is not correct.
(d) Assertion is not correct, reason is correct.
(e) Both assertion and reason are not correct.
Answer:
(d) Assertion is not correct, reason is correct.

21. Which of the following statement is correct?
(a) Ex-situ conservation is the conservation of a species in places of their natural homes.
(b) Ex-situ conservation is the conservation of species in Botanical gardens.
(c) Ex-situ conservation is the conservation of animals/plants in places outside their natural homes.
(d) None of the above
Answer:
(c) Ex-situ conservation is the conservation of animals/plants in places outside their natural homes.

22. Choose the incorrect statement:
(a) Biodiversity is the variety of all life on Earth.
(b) To date, about one million species have been identified on Earth.
(c) Sacred groves feature in various cultures throughout the world.
(d) None of the above.
Answer:
(b) To date, about one million species have been identified on Earth.

23. Identify the correct statement:
(a) Pollution is the only major cause of biodiversity loss.
(b) Species have been evolving and dying out ever since the origin of life.
(c) Nowadays, the species are becoming extinct at a slower rate.
(d) All the above statements are correct.
Answer:
(b) Species have been evolving and dying out ever since the origin of life.

24. Find out the incorrect statement:
(a) The term biodiversity was first introduced by Edward Wilson.
(b) The term biodiversity was first coined by Walter Rosen.
(c) The term biodiversity was popularised by Edward Wilson.
(d) None of the above.
Answer:
(a) The term biodiversity was first introduced by Edward Wilson.

Students get through the TN Board 12th Bio Zoology Important Questions Chapter 10 Organisms and Population which is useful for their exam preparation.

TN State Board 12th Bio Zoology Important Questions Chapter 10 Organisms and Population

Very short answer questions

Question 1.
Define Ecosphere.
Answer:
Ecosphere is defined as the largest and nearly self-sufficient biological system which includes all the living organisms of the Earth. They interact with the physical environment to regulate their distribution abundance, production, and evolution.

Question 2.
Name the abiotic factors of an environment.
Answer:
The abiotic factors of an environment include light, temperature, pressure, water, and salinity.

Question 3.
Define the niche of an organism.
Answer:
The niche of an organism is defined as the total position and function of an individual in its environment.

Question 4.
What is Van’t Hoff’s rule?
Answer:
Van’t Hoffs’s rule is that with the increase of every 10°C, the rate of metabolic activity doubles, or with the decrease of every 10°C, the metabolic rate is halved.

Question 5.
Define Phototaxis.
Answer:
Phototaxis is defined as the movement of an organism in response to light.
Eg: Moth (Positive Phototaxis), Earthworm (Negative Phototaxis).

Question 6.
Define porosity of soil.
Answer:
The porosity of the soil is defined as the percentage of soil volume occupied by pore space or by interstitial space.

Question 7.
Name any two plants present in hot deserts.
Answer:

1. Agave
2. Euphorbia

Question 8.
What is meant by cold deserts?
Answer:
Cold deserts are referred to as places where cold with snowfall and high overall rainfall throughout the winter and occasionally during summer.

Question 9.
Define population.
Answer:
The population is defined as any group of organisms of the same species, which can interbreed among themselves.

Question 10.
Explain population dispersion.
Answer:
Population dispersion is the tendency of the population to disperse or spread out in all directions until some barriers are reached.

Question 11.
What is meant by relative abundance?
Answer:
Relative abundance is a time-related index, which can show the changes in number in a population with respect to time. Eg: The number of birds of a particular species spotted in a unit area over a period of time.

Question 12.
Mention the factors, that regulate a population.
Answer:

1. Extrinsic factors. Density independent.
2. Intrinsic factors. Density-dependent.

Short answer questions

Question 1.
Distinguish between anadromous migration and catadromous migration.
Answer:

Anadromous Migration	Catadromous Migration
Anadromous migration is the migration of organisms from sea to freshwater. Eg: Salmon fish.	Catadromous migration is the migration of organisms from freshwater to sea. Eg: Eel.

Question 2.
What is structure adaptation? Give one example.
Answer:
Structural adaptation is the modification of the external and internal structures of an organism to suit them to adapt better to their environment.
Eg: Growing thicker fur in mammals to withstand the freezing climate in Arctic regions.

Question 3.
List out the adaptations of desert animals.
Answer:
The desert animals possess special adaptations to cope up with the desert environment. They are:

1. The animals living in the desert are capable of taping available water and storing sufficiently to withstand the heat.
2. Small nocturnal carnivores are predominant animals in the desert.
3. They are burrowers having cursorial, fossorial, and saltatorial adaptations.

Question 4.
Explain briefly about relative humidity.
Answer:
The amount of water vapor present in the air is known as relative humidity. It is expressed as a percentage of the amount needed for saturation at the same temperature. At a given temperature, a high percentage of humidity means that the air mixture is more humid. Humidity can be measured using an instrument called a Hygrometer.

Question 5.
Mention any three functions of soil.
Answer:
The functions of soil include:

1. The soil forms a medium for plant growth.
2. Soil is meant for water storage and purification.
3. Soil is the habitat for many organisms, which in turn modify and enrich the soil.

Question 6.
Explain the term “Photokinesis”.
Answer:
Photokinesis is a change in the speed of locomotion in the motile organisms or cells in response to a change in light intensity. This change of movement (or frequency of turning) is brought out by the change in the intensity of light. The movement may be undirected random movement of an organism in response to light.

Long answer questions

Question 1.
Give an account of adaptations of animals in response to temperature.
Answer:

1. Temperature is one of the major abiotic factors of the environment, which decide the survival of an animal in a particular environment.
2. The survival of an organism in an environment depends on its adaptation to temperature. Eurytherms are organisms, which can survive a wide range of temperatures.
   Eg: Cat, dog, tiger, and human.
3. Eurythmy is an aspect of thermoregulation in animals. Cold erythema is the adaptation of animals for the survival of the species during the ice ages. The ability of animals to survive in a wide range of temperatures increases a species ability to inhabit other areas – an advantage for natural selection.
4. Stenotherms are animals that can tolerate a narrow range of temperatures. Eg: Fish, frogs, lizards, and snakes.

The adaptation includes:

1. In the case of extreme temperatures, organisms have adapted by forming heat-resistant spores, cysts. Eg: Entamoeba
2. They form antifreeze protein to withstand severe cold.
   Eg: Arctic fishes.
3. They adapt to hibernation (Winter sleep) and aestivation (Summer sleep).
4. In certain conditions, migration is an appropriate adaptation to overcome extreme temperatures.

Question 2.
Draw and label the graphical representation of types of organisms based on temperature tolerance.
Answer:

Question 3.
List out any five adaptations of aquatic animals.
Answer:
The adaptations of aquatic animals include the following:

1. In fish, the pectoral fins and dorsal fins act as balancers and the caudal fin helps in changing direction as a rudder.
2. Streamlined body structure helps in the swift movement of animals in the water.
3. The presence of an air bladder filled with air helps for buoyancy.
4. Integument rich in mucous glands is protected by scales.
5. With well-developed excretory organs, they maintain water and ionic balance in their body.

Question 4.
Give an account of the role of migration in a population.
Answer:
Migration is the mass movement of a population from one place to another and back.
Migration is a peculiar and unique kind of mass movement to avoid extreme conditions of weather. The Siberian cranes migrate from Siberia to Vedanthangal in TamilNadu, in order to avoid severe winter cold in Siberia. Likewise, some fishes migrate from sea to freshwater (anadromous migration Eg: salmon) and some fresh water to sea (catadromous migration Eg: Eel).
Migration is of two types Emigration and Immigration.
Emigration: It is the type of migration outside the habitat, due to overcrowding of the population. This helps to prevent over-exploitation of habitat. It leads to the establishment of new habitat.
Immigration: It refers to the movement of population into the habitat from outside. It results in population levels. If the population increases beyond the carrying capacity of the habitat, it can result in increased mortality of immigrants or decrease the reproductive capability of individuals.

Choose the correct answers:

1. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(b) (p)-(iv); (q)-(i); (r)-(ii); (s)-(iii)

2. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(b) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
(d) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
Answer:
(c) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)

3. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii);'(s)-(i)
(b) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(d) (p)-(iii); (q)-(iv); (r)-(ii); (s)-(i)
Answer:
(c) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

4. Match the following:

(a) (p)-(iv); (q)-(iii); (r)-(ii); (s)-(i)
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)
(c) (p)-(ii); (q)-(i); (r)-(iv); (s)-(iii)
(d) (p)-(iii); (q)-(iv); (r)-(i); (s)-(ii)
Answer:
(b) (p)-(iv); (q)-(iii); (r)-(i); (s)-(ii)

5. Ethology is the scientific study of:
(a) animal reproduction
(b) plant reproduction
(c) animal behaviour
(d) plant response to light
Answer:
(c) animal behavior

6. Arrangement of body muscles in the form of bundles help in:
(a) metabolism
(b) locomotion
(c) hunting
(d) predation
Answer:
(b) locomotion

7. In the pond ecosystem, the column feeder is:
(a) catla
(b) mrigal
(c) common carp
(d) rohu
Answer:
(d) rohu

8. Tundra herbivores include:
(a) Arctic hare
(b) Snowy owl
(b) Arctic fox
(d) Bob cat
Answer:
(a) Arctic hare

9. Choose the odd one out:
(a) Light
(b) Temperature
(c) Water
(d) Soil microbes
Answer:
(d) Soil microbes

10. Identify the odd one:
(a) Polar bear
(b) Elephant
(c) Gaur
(d) Antelope
Answer:
(a) Polar bear

11. Find out the odd one:
(a) Trachea
(b) Gills
(c) Air bladder
(d) Lungs
Answer:
(c) Air bladder

12. Choose the odd one:
(a) Population density
(b) Ecological density
(c) Crude density
(d) Fecundity
Answer:
(d) Fecundity

13. Choose the correct pair.


Answer:
(b)

14. Find out the correct pair.

Answer:
(c)

15. Choose the incorrect pair.

Answer:
(d)

16. Which of the following is incorrect pair?

Answer:
(c)

17. Assertion: In a tropical forests, the soil nutrient-poor and acidic.
Reason: Decomposition is rapid and soils are subject to heavy leaching.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

18. Assertion: Grassland biome often is characterized by high winds.
Reason: Dense tree cover is not present in the Grassland biome.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.

19. Assertion: Clay soil has a high water retention capacity due to high porosity.
Reason: The pore space between soil particle are more in clay soil.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(e) Both Assertion and Reason are wrong.

20. Assertion: in aquatic media, maintaining homeostasis and osmotic balance is a challenge.
Reason: Marine animals have appropriate adaptations to prevent cell shrinkage.
(a) Both Assertion and Reason are correct, Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.
(c) Assertion is wrong, Reason is correct.
(d) Assertion is correct, Reason is Wrong.
(e) Both Assertion and Reason are wrong.
Answer:
(b) Both Assertion and Reason are correct, Reason is not the correct explanation of Assertion.

21. Choose the correct statement:
(a) Light does not influence reproduction.
(b) Light does not influence the growth of an organism.
(c) Light influences pigmentation.
(d) None of the above.
Answer:
(c) Light influences pigmentation.

22. Find out the incorrect statement:
(a) Water holding capacity of soil is directly dependent on soil porosity.
(b) Water holding capacity of soil is inversely dependent on soil porosity.
(c) Soil permeability is directly dependent on pore size.
(d) None of the above.
Answer:
(a) Water holding capacity of soil is directly dependent on soil porosity.

23. Choose the correct statement:
(a) Tundra biomes have long summers and short winters.
(b) Tundra biomes have long winters and short summers.
(c) Tundra biomes have little daylight in summer and long daylight in winter.
(d) None of the above.
Answer:
(b) Tundra biomes have long winters and short summers.

24. Which of the following statement is not correct?
(a) In aquatic animals, respiration is by gills.
(b) Presence of air bladders filled with air helps buoyancy.
(c) In fish, pectoral fins and dorsal fins act as balancers.
(d) None of the above statements is correct.
Answer:
(d) None of the above statements is correct.