1st PUC Biology Question Bank Chapter 1 The Living World

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Karnataka 1st PUC Biology Question Bank Chapter 1 The Living World

1st PUC Biology The Living World NCERT Text Book Questions and Answers

Question 1.
Why are living organisms classified?
Answer:
Classification is a method of grouping living organisms into convenient categories based on some observable characters which make their study easier.
For example, mammals are those who possess mammary glands, hair on body, external pinnae etc.

Question 2.
Why are the classification systems changing every now and then?
Answer:
New Organisms are being found by extensive research and new technology. So to accommodate them under classification. Classification changes every now and then.

Question 3.
What different criteria would you choose to classify people that you meet often?
Answer:
In our day to day life we categorize people based on the following criteria:

1. Level of education
2. Profession
3. Height and skin colour
4. Native place
5. Sex
6. Hobbies
7. Nature

Question 4.
What do we learn from the identification of individuals and populations?
Answer:
By identification of individuals/ populations, one can learn about their life: style, geographical habitation, culture, social and economic status, language, food (appetite), beliefs, and their effect on other people/populations.

Question 5.
Given below is the scientific name of Mango.
Identify the correctly written name,
(a) Mangifera Indica
(b) Mangifera Indies
Answer:
(b) Mangifera indica

Question 6.
Define a taxon. Give some examples of taxa at different hierarchical levels.
Answer:
A taxon is a group of real organisms contained in any category. A natural taxon refers to a group of similar, genetically related individuals having certain characters distinct from those of other group.
For example, all the insects form a taxon. So do birds, reptile, algae, grasses, dog, lion and man. Some examples of taxa at different hierarchical levels are:

• The taxon of bacteria is monera and their category is the kingdom.
• The sponges from the taxon Porifera and their category is phylum.
• Rosa is a taxon and genus is its category.

Question 7.
Can you identify the correct sequence of taxonomical categories?
(a) Species → Order → Phylum → Kingdom
(b) Genus → Species → Order → Kingdom
(c) Species → Genus → Order → Phylum
Answer:
From chart previous question
(a) and
(c) are correct.

Question 8.
Define and understand the following terms:
(i) Phylum
(ii) Class
(iii) Family
(iv) Order
(v) Genus
Answer:
(i) Phylum:
phylum is the next higher category after the kingdom. Classification is done based on broad features of animals or plants. For example, Chordates are classified due to the presence of a notochord and dorsal hollow neural system.

(ii) Class:
This is the next highest category after phylum. The class includes related orders. Class focused on more detailed features than broad architecture, for example, Mammalia consists of order primates comprising monkey, gorilla, gibbon and the order Carnivora including tiger, cat and dog, and other orders, which implies all animals having mammary glands and hairy body are grouped together.

(iii) Family:
Family is a group of related genera with still less number of similarities as compared to genus and species. Families are characterised on the basis of both vegetative and reproductive features of plant species. For example, three different genera Solanum, Petunia, and Datura are placed in the family Solanaceae. Among animals genus Panther, genus Felis is placed in family Felidae.

(iv) Order:
Order and other higher categories are identified based on the aggregate of characters whereas categories like genus, species and families were based on a number of similar characters. For example the families Canidae and Felidae which have many similarities and dissimilarities are classified into order Carnivora, similarly plant families like Convolvulaceae, Solanaceae are included in the order polemoniales.

(v) Genus:
Genus comparison is a group of related species which has more characters in common in comparison to species of other genera. We can say that genera are aggregates of closely related species. For example, potato and brinjal are two different species but all belong to the genus Solanum. Lion, leopard, and tiger with several common features, are all species of the genus Panthera, This genus differs from another genus Felis which includes cats.

Question 9.
How is a key helpful in the identification and classification of an organism?
Answer:
Key refers to a set of alternate characters in such a manner that helped for the identification of plants and animals by selecting and eliminating the characters according to their presence or absence in the organism.

Every taxonomic category like family, genus and species has separate taxonomic key. There is species key for the identification of species in a genus and genus key is for the identification of genus in a family and so on.

Question 10.
illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.
Answer:
Plant:

• Plant – Mango
• Kingdom – Plants
• Phylum – Angiospermae
• Class – Di cotyledonae
• Order – Sapindales
• Family – Anacardiaceae
• Genus – Mangifera
• Species – indica

Animal:

• Animal – Man
• Kingdom – Animalia
• Phylum – Chordates
• Class – Mammalia
• Order – Primates
• Family – Hominidae
• Genus – Hormo
• Species – sapiens.

1st PUC Biology The Living World Additional Questions and Answers

1st PUC Biology The Living World One Mark Questions

Question 1.
Name the three codes of nomenclature.
Answer:
international codes of botanical, zoological, and bacteriological nomenclature

Question 2.
Define Species.
Answer:
Species is the lowest level of organization and organisms can interbreed to produce fertile offspring.

Question 3.
What is taxonomy?
Answer:
Taxonomy frames the rules for classification. It is the branch of biology which describes the theory and practice of identifying and classifying living organisms.

Question 4.
What is taxon?
Answer:
Any classification group or category is called taxon.

Question 5.
Write the scientific name of coconut.
Answer:
Cocos nucifera.

Question 6.
What is a key?
Answer:
IK key is an analytical scheme for identification of plants and animals based on the similarities and differences.

Question 7.
Name the scientific method of naming a species used by Carolus Linnaeus?
Answer:
Binomial Nomenclature.

Question 8.
Who found Viruses are Crystallizable?
Answer:
Stanley.

Question 9.
What is a Capsid?
Answer:
The outer protein coat is called capsid.

Question 10.
Give the number and names of obligatory taxonomic categories.
Answer:
There are 7 obligatory categories that are: Kingdom – Phylum/Division – Class – Order – Family – Genus – Species

Question 11.
Which virus causes brain fever?
Answer:
Japanese Encephalilis virus.

Question 12.
Mention the Nucleic acid of HIV. (Dharwar 04)
Answer:
Single-stranded RNA.

Question 13.
Which is the nucleic acid found in bacteriophages? (B’lore North 05)
Answer:
Double-stranded DNA.

Question 14.
What are Methanogenic bacteria?
Answer:
The bacteria produce methane are called methanogenic bacteria.

Question 15.
Who is the father of Taxonomy?
Answer:
The Father of taxonomy is Carolus Linnaeus: a Swedish botanist.

Question 16.
What are Autotrophs? (B’lore North 04)
Answer:
The organisms that synthesize their own food are called autotrophs.

Question 17.
Who discovered bacteria?
Answer:
Anton von Leeuwenhoek.

Question 18.
Give one example to Nitrifying bacteria.
Answer:
Nitrosomonas.

Question 19.
What are antibiotics?
Answer:
They are the chemical substances produced by microorganisms which they Inhibit the growth of microorganisms.

Question 20.
Name the bacteria which causes typhoid and TB. (Bijapur 05)
Answer:
Typhoid is caused by Salmonella typhi.
TB is caused by Mycobacterium tuberculosis.

Question 21.
Mention the Characteristic blue pigment of Nostoc.
Answer:
Phycocyanin.

Question 22.
What are Planktons ?
Answer:
Microscopic free-floating plants or animal organisms of water are called planktons.

Question 23.
Why Protists are Eukaryotes?
Answer:
Protists contain eukaryotic cell that is cells of protists contain true nucleus (Nucleus with nuclear membrane so protists are eukaryotes.

Question 24.
What is Isogamy/Anisogamy?
Answer:
Fusion between similargametes is isogamy. The fusion between dissimilar gametes is anisogamy.

Question 25.
What is an algal bloom?
Answer:
Heavy growth of algae in water body or luxurious growth of algae in water is called algal bloom.

Question 26.
Name the pigment that gives golden brown colour to Diatom. (Dharwar 2005)
Answer:
Diatomin.

Question 27.
Which organism is commonly called ‘Pond Silk’? (D.Kannada 2009)
Answer:
Spirogyra.

Question 28.
What are Saprobes?
Answer:
Organisms feeding on dead organic mat¬ter and obtain their source of food are called saprobes

Question 29.
What is Mycelium? (B’lore South, Dharwar 04, Udupi 08, D.K.2009)
Answer:
Mycelium is the fungal body made up of a group of hyphae.

Question 30.
Name the first discovered Antibiotic.
Answer:
Penicillin

Question 31.
What are Hyphae?
Answer:
Hyphae are long filamentous, branched Or unbranched, septate Or a septate structure of mycelium.

Question 32.
What is Mycelium? (B’lore South, Hassan, Tumkur, Kolar, Dharwar2005)
Answer:
The fungal body is called mycelium made up of group of thread-like hyphae.

Question 33.
Mention any one harmful effect of fungi. (M.Q.P. 05)
Answer:
They cause diseases in plants (Koleroga), animals (Athlete foot) and humans (Aspergillosis).

Question 34.
Why are deuteromycetes named ‘imperfect fungi’? (D.Kannada 2008)
Answer:
Deuteromycetes are termed ‘imperfect fungi’ because only their asexual reproductive stages are known.

Question 35.
What is slippered animalcule?
Answer:
Paramecium. (Shimoga District 2004)

Question 36.
State the occurrence and function of the Cilia. (D. Kannada 2008)
Answer:
Cilia found in phylum protozoa & repre¬sent locomotor organs.

Question 37.
Name the locomotor organelles of class Rhizopoda /Sarcodina?
Answer:
Pseudopodia (false feet)

Question 38.
Who proposed the five-kingdom classification? (B. South 05, D. K, U.K. 2008)
Answer:
R. H. Whittaker

Question 39.
Who is the father of Biology?
Answer:
Aristotle.

Question 40.
Differentiate between aplanospores and conidia.
Answer:
Aplanospores are formed endogeously so, within the sporangia whereas conidia is formed exogenously, outside sporangia.

Question 41.
What are 2 kingdom in two kingdom classification?
Answer:
Animals and plants.

Question 42.
What are the 2 types of coco motion in Monera?
Answer:
Flagella and gliding.

Question 43.
What do you mean by term Amphitrichous and Lophotrichous?
Answer:
Amphitrichous: One flagellum at each of the two end of a cell.
Lophotrichous: One tuft of flagella at each of the two ends of a cell.

Question 44.
What are phytoplankton?
Answer:
Microscopic, autotrophic organisms, that are passively floating on the surface of water are called phytoplankton.

Question 45.
In what form is food stored in Euglena?
Answer:
Starch.

Question 46.
What maintains the cell shape of Euglena and paramecium?
Answer:
Pellicle.

Question 47.
Write the scientific name of a heterothallic fungus.
Answer:
Rhizopus stolonifera.

Question 48.
What is a zygo spore?
Answer:
Zygo spore is a product of fusion of gametes in certain fungi.

Question 49.
What is the method of sexual reproduction in Basidiomycete?
Answer:
Somatogamy.

Question 50.
Name the two phases in the life-cycle of a plant.
Answer:
Sporophyte an gametophyte.

Question 51.
In what force is carbohydrate store in animal cells?
Answer:
Glycogen.

1st PUC Biology The Living World Two Marks Questions

Question 1.
What is systematics? Discuss the criteria of artificial classification.
Answer:
Systematics is the branch of science that deals with the kinds and diversify of all organisms. The system is highly useful in the field for quick identification of organisms. The artificial system often utilizes one or two morphological traits.

Question 2.
Write the differences between Virus and Viroid.
Answer:

• Virus consists outer protein coat called capsid and inner nucleic acid (DNA or RNA). Viroid consists only RNA without protein.
• Virus causes disease to animals and plants. Viroid causes diseases to plants only.
• Some viruses contain DNA as their genetic – material and others contain RNA. Viroids contain only RNA as their genetic material.

Question 3.
What is symbiosis ? Give an example to symbiotic bacteria.
Answer:
’Living together of two different groups of organisms and deriving equal benefit is called symbiosis. Rhizobium is an example to symbiotic bacteria.

Question 4
Write the names of different shapes of Bacteria. (Gulbarga 2005)
Answer:
Cocci, Bacilli, Spin Hum, are different shapes of bacteria.

Question 5.
What is the benefit of manuals and records for the scientific study of living beings?
Answer:
Manuals and records basically helps in understanding past flora and fauna of a given area. Take an example of a thriving city. There may had been a dense forest, rich in biodiversity, where we get to see densely populated cities today.

The manuals and records of that area helps us in knowing about past richness in biodiversity. We also come to know extinct species, through manuals and records. Some of the extinct species may be close or distinct relatives of some existing species. We can develop some evolutionary relationships between them.

Question 6.
Write any two differences between Archaea and Eubacteria.
Answer:

• The cell wall of eubacteria contains peptidoglycan.
  The ceil wall of archaea contains protein, glycoprotein or Polysaccharides.
• Plasma membrane of archaea is made up of long-chain of lipids and chain is branched. In eubacteria, plasma membrane is made up of Long-chain fatty acids bound to Glycerol.

Question 7.
Explain Heterocyst.
Answer:
Large oval or barrel-shaped of thick-walled cell present in a trichome is called heterocyst. A trichome consists single heterocyst. It is terminal or intercalary in position. The terminal heterocyst contains single polar nodules and single polar pore whereas intercalary heterocyst contains two polar nodules and two polar poles. Heterocysts contain nitrogenase enzyme helps for nitrogen fixation.

Question 8.
Explain the role of blue-green algae in soil fertility.
Answer:
The hierarchy includes seven obligate categories —kingdom, division or phylum, class, order, family, genus, and species.
The categories are arranged in descending sequence. In order to make the taxonomic position of species more precise, certain categories that have been added to this list are called intermediate categories e.g., sub-kingdom, superphylum or super division, subdivision, superclass, subclass, superorder, suborder, superfamily, sub-family, tribe, subspecies, variety, etc.

Question 9.
List any four divisions of the Kingdom Protista based on morphology.
Answer:
Division :

• Pyrophyta
• Chrysophyta
• Euglenophyta
• Protozoa.

Question 10.
List any four characteristics of Protista. (Belgaum 2004)
Answer:

• Protists are unicellular eukaryotes so that they contain true nucleus and cytoplasmic organelles like mitochondria, Golgi body, etc.
• They show different types of nutrition. Some are photoautotrophs others are heterotrophic. Heterotrophs are saprophytes or parasites. Some protists show animal-like holozoic nutrition.
• Some protists possess locomotory organelles like pseudopodia, flagella, cilia, etc.
• Protists show both asexual and sexual reproduction.

Question 11.
Write any two distinguishing characters of Fungi.
Answer:

• Fungi are nonchlorphyllous, nonphotosynthetic saprobes
• fungal bodies called mycelium and it is made up of branched Or unbranched septate or a sep¬tate filaments called hyphae

Question 12.
mention any two divisions of Fungi and give one example each.
Answer:

• Division – Zygomycota
  Example: Rhizopus.
• Division – Ascomycota
  Example: yeast.

Question 13.
Write two important features of kingdom Mycota. (Bangalore South 05)
Answer:
Kingdom mycota includes non-chlorophyllous heterotrophic forms. The fungal body is termed mycelium made of a number of hyphae.

Question 14.
Give four characters of Protozoa? (Dharwar, Bangalore South.04, Udupi 08, D.Kannada 2009)
Answer:
Characters of Protozoa are as follows.

• Unicellular, microscopic organisms with a protoplasmic grade of construction.
• They are uninucleate or Binucleate. When binucleate, one nucleus is larger (Macronucleus) and other is small (Micronucleus).
• Locomotion is by Pseudopodia, cilia or flagella.
• Nutrition is holophytic or holozoic or saprophytic or parasitic.

Question 15.
Write the general characters of the Kingdom Monera. (8 characters).
OR
List any four characters of the kingdom Monera. ‘ (Hassan2005)
Answer:

• Minerals are Prokaryotes i.e.., they do not contain a true nucleus.
• Nuclear membranes is absent.
• Cell wall of minerals is made up of Murein.
• Cytoplasmic organelles like mitochondria, Golgi body, Endoplasmic reticulum are absent.
• Ribosomes are 70S type.
• The Genetic material is double-stranded DNA which is in the form of circular loop. It is called Nucleoid. It is free from histone proteins.
• Photosynthetic monerans contain pigments and pigments are present inside lamellae but not in chloroplasts.
• Mode of Nutrition is Autotrophic or Heterotrophic Cell division does not involve mitosis and meiosis

Question 16.
Name the five kingdoms of life.
OR
Name five kingdoms of classification of Organisms. (Gulbarga B. North. 2004)
Answer:
Kingdom Monera,

• kingdom: Protista,
• Kingdom: Mycota,
• Kingdom: Metaphyta,
• Kingdom: Metazoa.

Question 17.
Give two characteristics of Kingdom Monera.
Answer:

• All monerans are Prokaryotes, so that they do not contain true nucleus.
• They do not contain mitochondria, Endoplasmic reticulum, Golgi body etc. But ribosomes are present they are 70 S type.

Question 18.
Give two characteristics of Kingdom Mycota.
Answer:

• Members of mycota are called fungi and they are Nonchlorophyllous Saprophytes,
• Fungal body is mycelium.

Question 19.
Give two characteristics of Kingdom Protista.
Answer:

• They are unicellular or colonial eukaryotic organisms without tissue differentiation.
• Cytoplasmic organelles like mitochondria, Endoplasmic reticulum, etc. are present.

Question 20.
Give two characteristics of Kingdom Metaphyta.
Answer:

• Members of the kingdom are plants and they are multicellular, Eukaryotes and body shows tissue and organ grade of construction,
• They store starch as their reserve food material.

Question 21.
Give two characteristics of Kingdom Metazoa.
Answer:

• Members of this kingdom are animals and they are multicellular, eukaryotes and ani-mal body show tissues and organ level of construction.
• They are heterotrophs and show locomotion.

Question 22.
Differentiate between oxygenic anoxygenic photosynthesis.

Oxygenic photosynthesis	Anoxygenic photosynthesis
(a) type of photosynthe­sis in which oxygen is liberated as a by-product	(a) type of photosynthe­sis in which oxygen is not liberated as a by-product
(b) performed by higher organise like plants	(b) performed by primitive organise like bacteria

Question 23.
What are the characteristic features of Eugienoide?
Answer:

• Eugienoide are freshwater organisms found in stagnant water
• Instead of a cell wall, they have a protein-rich layer called pellicle which make this body flexible.
• They have two flagella, a short and a long one.
• Though they are photosynthetic in the presence of sunlight, when derived of sunlight they behave like heterotrophs by predating on other smaller organisms.
• pigments of euglenoids are identical to those present in higher plants.
  eg: Euglena.

Question 24.
How are ascomycetes different from Basidiomycetes?
Answer:

Ascomycetes	Basidiomycetes
(a) The fruiting body called ascocarp	(a) The fruiting body is called basidiocarp
(b) each as we contain 8 ascospores within	(b) Each basidium produces for basic diaspores exiguously
(c) They may or may not show dikaryotic phase in the life cycle	(c) The show or extended period of dikaryotic phase in the life cycle
(d) Asexual spores are found	(d) Asexual spores are not found.

1st PUC Biology The Living World Five Marks Questions

Question 1.
What are the advantages of scientific names?
Answer:

Question 2.
Mention all the Taxonomic aids and briefly describe them.
Answer:
The collection of specimens that help in the identification of a species are called taxonomic aids.  Some of the taxonomic aids are

(i) Herbarium:
A herbarium is defined as a collection of plants that have been dried, pressed and preserved on sheets. These sheets are arranged in accordance with any accepted system of classification and they form a repository for future use.

(ii) Botanical Gardens:
These specialized gardens have collections of living plants for reference. Plant species in these gardens are grown for identification purposes and each plant is labelled indicating its scientific name and its family.

(iii) Museum:
Biological Museums are those places which have a collection of preserved animals and plants for taxonomic studies.

(iv) Zoological parts:
These are places that have wild animals kept in protected environments under human care and which enable us to learn about their food habits and behaviour.

(v) Keys:
A key is an analytical scheme for the identification of plants and animals based on the similarities and differences.

Question 3.
Describe the steps involved in the classification of an organism.
Answer:
The following are steps involved in classifying an organism

• The organism has to be described for all its morphological and other characteristics
• Based on its characteristics; it is identified for its similarities or differences to any known group or taxon
• It is then placed in a known taxon based on its similar characters
• If it is different from the ones already described anywhere in the world, it is placed in a new group and then named.
• If the organism has not been described before, it is given a new name; or its correct name is determined.

Question 4.
Write a short note on Keys.
Answer:
A Key is an analytical scheme for the identification of plants and animals based on the similarities and differences. The keys are based on the contrasting characters, generally in a pair called couplet. Each couplet actually represents the choice made between two opposite options, leading to the acceptance of one Each statement in the key is called a lead keys are of two types.

• Indented keys, which provides a sequence of choices between two or more statements of character of species
• Bracketed keys, where pairs of contradict-ing characters are used for identification, the number on the right of the statement indicate the recent choice of paired contrasting statements.

Question 5.
Write a note on flora, Manuals and Mono-graph.
Answer:
(1) Monographs:
Monograph gives a comprehensive account of complete compilation of available information of anyone’s family or genus at a time.

(2) Manuals:
Manuals contain compiled information about the particular area, key, descriptions of family, genus and species.

(3) Flora:
flora contains the actual description of the habitat and distribution of plants in a given area. We have several floras in India e.g: flora of British India, flora of simensis, flora of Delhi etc.

Question 6.
Write the general characters of the Kingdom Monera. (8 characters).
Answer:

• Monerans are Prokaryotes i.e., they do not contain true nucleus.
• Nuclear membrane is absent.
• Cell wall of monerans is made up of Murein.
• Cytoplasmic organelles like mitochondria, Golgi body, Endoplasmic reticulum are absent.
• Ribosomes are 70S type.
• The Genetic material is double-stranded DNA which is in the form of a circular loop. It is called Nucleoid. It is free from histone proteins.
• Photosynthetic monerans contain pigments
  and pigments are present inside lamellae but not in chloroplasts.
• Mode of Nutrition is Autotrophic or Heterotrophic. Cell division does not involve mitosis and meiosis.

Question 7.
Write the general characters of the Kingdom Mycota. (8 characters).
Answer:

• Members of this kingdom are called fungi. They are non chlorophyllous, saprophytes. Some are parasites.
• Fungal body is called Mycelium. It consists of branched or unbranched filaments called hyphae.
• Cell wall is made of fungal cellulose or chitin.
• They are unicellular of multicellular Eukaryotes.
• They store glycogen and oil as their reserve food.
• Locomotion is generally absent.
• Mycelia is haploid in primitive forms and dikaryotic in advanced groups.
• Reproduction includes both asexual and sexual. Asexual stage involves spore formation.

Question 8.
Write the general characters of the Kingdom Protista. (8 characters).
Answer:

• They are unicellular, or colonial Eukaryotes.
• Diverse nutritive methods like photosynthesis, absorption, ingestion, etc.
• Cytoplasm has cell organelles such as Golgi complex, mitochondria, etc.
• Ribosomes are 80s type.
• They have locomotory organells such as flagella, celia, pseudopodia.
• Mitosis and meiosis are the two types of cell divisions.
• They reproduce asexually and sexually
• Formation of cyst is common for escaping from drought and other unfavorable conditions.

Question 9.
Write the general characters of the Kingdom Metaphyta. (8 characters).
Answer:

• Members of this kingdom are called plants and they are multicellular Eukaryotes.
• Cell wall is present made of cellulose.
• Mode of Nutrition is Autotrophic. They are photoautotrophs.
• Light capturing pigments called chlorophyll are present in Chloropiasts.
• Some plants are avascular and some others are vascular.
• Plant body shows tissue and organ level of construction.
• They are nonmotile but some organs like leaf, root and stems show growth movements
• They store starch as their reserve food material.

Question 10.
Write the general characters of the Kingdom Animal. (8 characters).
Answer:

• They are multicellular Eukaryotes.
• They are heterotrophs. Some are saprophytes and others are parasites.
• Animal cells lack cell wall.
• Majority of animals show locomotion.
• Body shows tissue and organ level of construction.
• They give a quick responses to the stimulus because they have well developed nervous system.
• In animals, some tissues like muscular tissue, nervous tissues are well developed,
• Animals show both asexual and sexual method of reproduction.

Question 11.
List the distinguishing characters of the phylum protozoan, and classify the phylum with examples. (B. South., B. North., Dharwar2004, Udupi 2005)
Answer:
Characters:

• Unicellular, microscopic, Protoplasmic grade of construction.
• Uninucleate or binucleate [Macro and Micro¬nucleus]
• Holophytic, Holozoic, Saprophytic or Parasitic mode of nutrition.
• Digestion intracellular. Respiration and excretion by diffusion.
• Contractile vacuoles regulate osmoregulation.
• Locomotion by Pseudopodia / Cilia / flagella.
• Reproduction by asexual (Binary fission and multiple fission), Sexual by conjugation or fusion of gametes.

Classification:

• Class – Rhizopoda / Sarcodina – Eg. Amoeba
• Class – Mastigophora/Flagellata Eg. Euglena
• Class – Ciliata – Eg : Paramecium
• Class – Sporozoa – Eg. Plasmodium

Question 12.
Write the general characters of Virus.
(Bangalore North 2005, D.Kannada 2007)
Answer:
General Characters

• Viruses are non cellular, so they do not possess, Cell walls, plasma membranes, cytoplasmic organelles.
• They are ultramicroscopic.
• They can be crystallized and stored inside bottles still they retain the capacity of infection.
• All viruses are obligate intracellular parasites.
• Chemically they have outer protein coat and inner core of genetic material DNA or RNA.
• Viruses multiply inside suitable host cells by the process of replication.
• Viruses are resistant to antibiotics.
• They undergo mutation.

Question 13.
Explain the type of bacteria based on their mode of Nutrition. (D.Kannada 2010)
Answer:
Based on nutrition bacteria are classified into the following types
(1) Autotrophic bacteria :
They synthesize their own food. They are further classified into two types ;

(A) Photoautotrophic bacteria :
They are autotrophs and synthesize their food by absorbing light energy. They contain bacteriochlorophyll and bacteriocidin to absorb light energy.
Example: Green sulphur bacteria like chlorobium, purple sulphur bacteria like chromatium. These bacteria use H₂S as their source of hydrogen, so O₂ is not liberated.

(B) Chemoautotrophic bacteria:
They are autotrophs, utilizes (utilises) chemical energy for food synthesis. They get chemical energy by the oxidation of chemical substances of nature. Example: Nitrifying bacteria, sulphur bacteria etc.

(2) Hetero trophic bacteria: They do not synthesize their own food but obtain food by two methods.

• Saprophytic method.
• Parasitic method.

The bacteria obtain their food by feeding on dead organic matter are called saprophytic bacteria. The bacteria obtain their food by living inside or outside the body of other organisms are called parasitic bacteria.

Question 14.
Mention any five beneficial activities of bacteria. (B’lore Rural 05, D.Kannada 08,2009)
Answer:

• Bacteria act as natures scavengers and play a vital role in the process of decay.
• Bacteria are industrially important i.e. dairy, leather, curing, retting, etc.
• They enhance soil fertility by their ability to fix atmospheric nitrogen.
• They are used to reduce pollution levels in water especially the breakdown of hydrocarbons like petroleum.
• Bacteria play a vital role in the hydrometallurgical industries for the extraction of metals from their ores.
• Bacteria are widely used for gene manipulation in genetic engineering experiments.

Question 15.
Explain any two beneficial aspects of Nostoc.
Answer:

• Nostoc species are useful to increase soil fertility. They fix atmospheric nitrogen. The heterocysts contain nitrogenase enzyme that helps for nitrogen fixation. So they are called biofertilizers.
• The balls of Nos toe commune a reused as food by Chinese and South Americans.
  Nostoc species are oxygenic like other blue-green algae. So O₂ released during the photo. synthesis.contributing to the O₂ content of the atmosphere.

Question 16.
Explain any two harmful activities of Blue-Green algae.
Ans Answer:

• Heavy accumulation of blue-green algae in water bodies bring algal bloom. Algal bloom makes water unfit for domestic use. After the death of these algae their dead organic matter creates rich source of food for aerobic bacteria. They decompose organic matter by consuming O₂. It creates O₂ deficit and causes the death of fishes.
• Some cyanobacteria grow on buildings during rainy season and cause damage to bricks and surface coating.

Question 17.
List the general characters of algae.
Answer:

• Algae are chlorophyllous, photosynthetic aquatic organisms and they are eukaryotes.
• They are unicellular, colonial or multicellular. The multicellular algae produce branched or unbranched filaments.
• Cell wall is made up of cellulose.
• Photosynthetic pigments are in plastids.
• They show both asexual and sexual reproductions.
• Asexual reproduction is by the formation of spores arid sexual reproduction is by isogamy of anisogamy.

Question 18.
Give the general features and classifica¬tion of Protista with examples.
Answer:
Features of Protista are

• Protists are unicellular eukaryotes so that they contain true nucleus and cytoplasmic organelles like mitochondria, Golgi body etc.
• They show different types of nutrition. Some are photoautotrophs others are heterotrophic. Heterotrophs are saprophytes or parasites. Some protists show animal-like holozoic nutrition.
• Some protists possess locomotory organelles like pseudopodia, flagella, cilia etc.
• Protists show both asexual and sexual reproduction.

Classification of Protista are :
Divisions

• Pyrophyta — Dinoflagellates
• Chrysophyta — Diatoms
• Euglenophyta — Euglena
• Protozoa. — Amoeba

Question 19.
Give an account of the distinguish characters of Fungi.
Answer:

• Fungi are nonchlorophyllous, non-photosynthetic saprophytes.
• Fungal body is called mycelium made up of filamentous structures are called hyphae
• Cell wall is made up of fungal cellulose OR chitin.
• Cells are eukaryotic with true nucleus and membrane-bound organells.
• Parasitic fungi produce haustoria to absorb food from host.
• The reserve food is glycogen and oil
• Fungi reproduce by a sexual and sexual method. Asexual reproduction is by fragmentation budding binary fission and by the formation of spores
• Sexual reproduction occurs by plasmogamy, karyogamy and many involve meiosis.

Question 20.
Explain the useful aspects of Fungi. (Udupi2006)
Answer:
Fungi are useful

1. Fung!as food: Mushrooms and morels are rich in protein vitamin and mineral contents so used at food.
2. Fungi as decomposers: Since most of them are saprophytes they decompose dead organic matter and help in recycling.
3. Fungi in drug industry : Many fungi are used in drug industry to extract useful antibiotics. Penicillin is a wonderful antibiotic extracted from Penicillium notatum.
4. Fungi and biological control: Several parasitic nematodes are controlled by fungi.

Question 21.
Describe the methods of asexual reproduction in fungi with a examples.
Answer:

1. Zoospores:- fungi living in fresh after produces zoospores, zoospores all non motile eg: saproleguca, pythim
2. sporangiosporce Hydarospores: These are non motile spores/produced within the sporan-gia, they are disseminated by wind eg: Rhizopul, mucor
3. Conidia: These are non-motile spores produced exogenously from the tip of conidiophores, they are also disseminated by wind, eg: Aspergillus, penicillium
4. Buddins: Under favorable conditions, yeast-like fungi reproduced by budding
5. fission: Under favourable conditions, yeast reproduce by fission where a cell divides into two daughter cells.

Question 22.
Describe different type of nutrition in fungi.
Answer:
Fungi are non-autotrophic (heterotrophism) is nature. The type of nutrition are

1. Symbionts: Some fungi like mycorrhizal and lichens live by symbiosis.
2. Parasites: Parasites are those organism which depend on other organisms for their food and shelter
   eg: puccinia
3. Saprophytes: These are fungi which depend on dead and decaying organisms for their food.
4. Arthnobotrys is a predaceous fungi, which feeds on nematodes.

1st PUC Biology The Living World Three Marks Diagrams:

Draw a neat labelled Diagrams of

Question 1.
Eugiena
Answer:

Question 2.
Nostoc
Answer:

Question 3.
Bacteriophage
Answer:

Question 4.
TWV
Answer:

Question 5.
Bacterial Ceil
Answer:

Question 6.
Bacterias of Different shape
Answer: