Biological Classification - Class 11 Medical Biology - Extra Questions

Which do you think is a more basic characteristic for classifying organism ?
(a) The place they live
(b) The kind of cells they are made of. Why?

The kind of Cells. Habitat is a place where diverse types of organisms live together. It cannot be used for classifying organisms. Cells have specific structure, prokaryotic in monerans and eukaryotic in the remaining organisms. Organisms are unicellular in protista and multicellular in others. A cell wall is absent in animals. Cell wall contains chitin in fungi and cellulose in plants. Plastids occur in plant cells. They are absent in animal cells.


Why are the classification systems changing every now and then?

Millions of plants, animals, and microorganisms found on earth, have been identified by the scientists while many new species are still being discovered around the world. Therefore, to classify these newly discovered species, with new characters, new systems of classification have to be devised every now and then. This creates the requirement to change the existing systems of classification.


What do the terms phycobiont and mycobiont signify?

  • Phycobiont refers to the algal component of the lichens and mycobiont refers to the fungal component.
  •  Both of these are present in a symbiotic relationship in which algae prepare food for fungi due to the presence of chlorophyll whereas the fungus provides shelter to algae and absorbs water and nutrients from the soil.


Short / Long answer type questions.
What are (a) methanogens, (b) halophiles, and (c) themoacidophiles?

(a) Methanogens are the bacteria that produce methane gas and are found in swamps, lakes, paddy fields, as symbionts in the lumen of many herbivores. They are responsible for methane gas production in biogas plants.
(b) Halophiles are the salt lover archaebacteria which occurs in extremely saline conditions and can survive under high salt concentration. They have the enzymes which can operate at high pH.
(c) Thermoacidophiles are archaebacteria found in hot sulphur springs and highly acidic environment, they are temperature and acid-loving bacteria.


How is archaebacteria different from eubacteria.

Archacbacteria are characterized by possessing cell walls without peptidoglycan, a substance found in the walls of eubacteria. The lipids in their plasma membrane are branched, differing not only from those of other bacteria. This unusual lipid makup is probably related to the extreme environments to which they have adapted. The phototrophic forms use the pigment bacteriorhodopsin instead of bacteriochlorophyll used by eubacteria.


Match the terms to these definitions.
Conjugation, transformation, transduction, phototrophs, saprotrophs, archaebacteria, actinomycetes, mycoplasma, thermoacidophiles, methanogens, halophiles, vibrio, Bacillus, micrococcus, helical, staphylococcus.
.......... characterised by possessing cell walls without peptidoglycan, a substance found in the walls of eubacteria.

 $$\underline {Archaebacteria}$$ is characterised by possessing cell walls without  peptidoglycan, a substance found in walls of Eubacteria.


Differentiate between.
Halophiles and thermoacidophiles.

Halophiles re those archaebacteria which are found in regions of high salinity, whereas thermoacidophiles are those archaebacteria which are found in hot sulphur springs.


Match the terms to these definitions.
Conjugation, transformation, transduction, phototrophs, saprotrophs, archaebacteria, actinomycetes, mycoplasma, thermoacidophiles, methanogens, halophiles, vibrio, Bacillus, micrococcus, helical, staphylococcus.
.......... a kind of archaebacteria, found in hot sulphur springs.

$$\Underline {Thermoacidophiles}$$ is a kind of archeabacteria, found in hot sulphur springs.


Fill in the blanks with approprite words.
.......... is a method of sexual reproduction where two hyphae meet together.

Two vegetative cells or two hyphae take over the sexual function and fuse together is called as Somatogamy which takes place in advanced fungal groups.


Fill in the blanks with approprite words.
A thick-strand of underground hyphae resembling a root is known as..........

rhizomorph


Very short answer type.
Observe the relationship between the first two words and then fill in the fourth place
moss : capsule , fern : ______

sporangium


What is a Lichen?

Lichen are organisms formed by a symbiotic relationship between algae and fungi. Usually the fungi is the host and algae or cyanobacteria is the symbiont. The algae performs photosynthesis and the fungi consumes the end product. However both the fungi and algae are capable of living independently.


Short / Long answer type questions.
How do the archae differ from the bacteria?

Archaebacteria are different from eubacteria as they lack peptidoglycans and cellulose in their cell wall, their cell wall is made up of non-cellulosic polysaccharides and proteins, archaebacteria can survive in harsh conditions but bacteria cannot.


What is the smallest Pathogen?

A pathogen is anything that causes a disease, that can be bacteria, viruses or anything.
We are in contact with pathogens every day. Most of the time the body's immunity system destroy the pathogen because it can harm us.
The pathogenic disease include bacterial meningitis disease, hepatitis A, hepatitis B, and athlete's foot


How did Whittaker classify the organisms? What was the basis for classification? 

R.H. Whittaker (1969) proposed a Five Kingdom Classification. The kingdoms defined by him were named Monera, Protista, Fungi, Plantae and Animalia. The main criteria for classification used by him include cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.


Match the terms to these definitions.
Ascus, mycelium, basidium, mycorrhiza, budding, conidiospore, rhizomorph, stroma, fruiting body, sporangium, fungus, hypha, spore, lichen, zygospore, apothecium.
..........A symbiotic association between a fungus and an alga, may live in stressful environment

lichen


What are (i) methanogens (ii) Halophiles (iii) thermoacidophiles?

(i) Methanogens: These are microorganisms that produce methane as a byproduct of metabolism in anoxic conditions. They belong to class Archaea.
(ii) Halophiles: These are microorganisms that grow and thrive in high salt concentrations. 
(iii) Thermoacidophiles: These are microorganism that are both thermophilic and acidophilic, that is they can grow under conditions of high temperature and low pH.


Very short answer type.
Name the three sub-kingdoms of Protista as proposed by Robert H. Whittaker.

The plant-like Protophyta. (photosynthetic autotrophs), the fungus-like Gynomycota (absorb externally digested nutrients), and the animal-like Protozoa (ingest nutrients hut digest them internally).


In which kingdom are viruses placed?

Viruses are classified as living organisms because they have very simple, noncellular structure and cannot exist independently. They are on the boundary between what we regard as living and non living, and hence, are not included in any kingdom under modem classification.


Five kingdom classification of living organisms is given by ..........

The Five Kingdom classification of organisms was given by Robert Whittaker in 1969. It includes kingdom Monera, Protista, Fungi,Plantae and Animalia.


Why is the virus called a mysterious microbe?

Viruses are mysterious because they fall on the threshold of living and non living beings. They are tiny microorganisms, about thousand times smaller than bacterial cells. Viruses do not have enzymes or the chemicals, which are important for life sustaining chemical reactions. Thus viruses need a host cell such as bacteria, plant or animal to exist, grow and reproduce to act like a living being. 


________ bacteria are microbes that work in the absence of oxygen.

For most organisms, they use oxygen during cellular respiration as an electron acceptor. Basically, the oxygen accepts electrons and turns into water or carbon dioxide. Obligate anaerobic bacteria survive in the absence of oxygen because they use other molecules as their primary electron acceptors. Common electron acceptors used by anaerobic bacteria include sulfate, nitrate, iron, manganese, and mercury



The cell walls in most fungi contain ________

The cell walls in most fungi contain chitin. Chitin is a complex polysaccharide which gives structural strength to the cell walls of fungi.


Unlike plant cell walls which are made of cellulose, most bacterial cell walls contain ...........

Unlike plant cell walls, which are made of cellulose, most bacterial cell walls contain peptidoglycan.


Short / Long answer type questions.
Describe briefly various methods of reproduction in bacteria and also the mechanism of transformation.

Reproduction in bacteria can occur through three methods:
  1. Binary fission: It occurs under favourable conditions.
  2. Sporulation: Occurs by endospore formation.
  3. Genetic recombination: It is a primitive type of DNA transfer from one bacteria to another and can occur in three ways:
  • a) Conjugation
  • b) Transduction
  • c) Transformation: In this method, bacteria absorbs the DNA from its dead relative present in surrounding and integrate it into its own nucleoid.


What are viruses? How do they differ from other microbes?

Viruses are microscopic organisms, generally very smaller than bacteria. They are parasitic in nature, i.e. they can thrive and reproduce only on the host cell like animals, bacteria and plants etc. 
Viruses are non-living in nature until they come in contact with the living cells. Most of the viruses are infectious in nature. Whereas some of the other microorganisms are useful in nature.Viruses can multiply very rapidly than the microorganisms. 


The given organism grows on a bread and commonly known as_______.

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$$\textbf{Correct answer:}$$ Mold


$$\textbf{Explanation:}$$

$$\bullet$$ Mold is the large and taxonomically diverse group of fungal species.

$$\bullet$$ Out of which, Rhizopus and Aspergillus are the commonly found molds on the bread.


$$\textbf{Conclusion:}$$ Mold have a heterotrophic mode of nutrition and are classified under the kingdom Fungi.




Name the microorganism.

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The given picture is of bread mould, also known as Rhizopus. Rhizopus belongs to the kingdom fungi. Bread moulds are generally found in warm and moist places like moist bread. Moisture is an important factor for the growth of these bread moulds.


Why are the protozoan placed in kingdom Protista and not in kingdom Animalia?

Protozoans are unicellular, eukaryotic organisms having a heterotrophic mode of nutrition. They are considered as the relatives of animals because of their motile nature and heterotrophic mode of nutrition. The kingdom Animalia includes all multicellular, eukaryotic, heterotrophic organisms whereas, the kingdom Protista includes all unicellular, eukaryotic and heterotrophic organisms. Hence, Protozoans are placed under the kingdom Protista instead of the kingdom Animalia.


What are haustoria?

Haustoria are bulb like ingrowths formed by parasitic organisms like certain fungi, plants (Cuscuta) to obtain nourishment from their host.


State two economically important uses of : 
(a) Heterotrophic bacteria
(b) Archaebacteria

Heterotrophic bacteria are microorganisms which survive by deriving their energy using organic matter from other sources rather synthesizing their own organic matter. The Heterotrophic bacteria have several economic applications; Lactobacillus and Streptococcus are widely used for the production of milk products like curd and cheese. Streptomyces is a genus of Gram-positive bacteria with the ability to produce bioactive secondary metabolites such as antifungals, antivirals, antitumoral, anti-hypertensives, and mainly antibiotics and immunosuppressives. Many different kinds of heterotrophic bacteria are used for sewage treatment. Some heterotrophic bacteria like Alcanivorax or Methylocella Silvestris have an important applications in bio-remediation (cleaning the oil spills). 
Archaebacteria are a group of prokaryotes which live under very harsh and hostile conditions. Since the enzymes from these organisms can survive harsh conditions they have many industrial applications in biotechnology; Many of the thermostable enzymes used in the manipulation of DNA are derived from Archaebacteria, Methanogens of the Archaebacteria are mainly involved in the biogas production. 


Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?

As a sample tap water or curd  can be used for the study of microbes. Tap water contains many kinds of bacteria (close to 80,000 bacteria in 1 ml of water) which can be observed under the microscope by simple staining procedures. Alternately, curd which is  made by the action of Lactobacillus bacteria on milk can also be easily observed under a microscope.


Which organisms act as an interlink between living and non-living organisms? Why do you think so?

Viruses act as an interlink between living and non-living organisms because: 
(a) They react like non-living things in the free atmosphere but when they enter into the body of a living organism then they start multiplication.
(b) They contain DNA or RNA within them.


What was the basis of early classifications?

  • The earliest classification systems comprised of only two kingdoms but with more research, more kingdoms were added with time.
  • The two kingdom system of classification was given by Carolus Linnaeus. He divided all organisms into two kingdoms, Plantae and Animalia.
  • Ernst Haeckel gave three kingdom system of classification in which he divided all the living organisms into three kingdoms, Plantae, Animalia and Protista. He added kingdom Protista for unicellular organisms and multicellular organisms without tissue.
  • Copeland gave four kingdom system of classification in which he divided all living organisms into four kingdoms, Monera having prokaryotic organisms, Protista having true nucleate organisms, Plantae having photosynthetic and multicellular organisms and Animalia having non photosynthetic and multicellular organisms.
  • RH Whittaker gave five kingdom system of classification in which he divided all organisms into five kingdoms Monera, Protista, Fungi, Plantae and Animalia on the basis of complexity of cell structures, body structure, mode of nutrition, life style and phylogenetic relationship.


Write the characteristics features of poxviruses.

The characteristic features of poxviruses are as follows:
  • It is the largest of all viruses and brick shaped. 
  • They contain double stranded DNA, protein and lipid. 
  • They have dumb-bell-shaped nucleoid surrounded by two membrane layers.
  • The infection results in the development of the rash on the skin. There is fever, head ache, fatigue, lesions, etc. 


List any two living characteristics of virus.

The two characteristics are as follows:

1. Viruses are neither living nor non-living. They have genetic material  DNA or RNA and reproduce only within the living cells and increase their number.

2. They are resistant to antibiotics and mutate their genetic material i.e., show mutations.



Viruses can be crystallized. What does this signify?

Crystallization is the method of transformation of viral components into organized solid particles. It includes a large number of viral particles. Crystallization of viral particles allows leads to understanding of their characteristics, pathogenic activity, mutational levels, nucleic acids and capsid properties, through X-ray, laser beams etc


List out the differences between enveloped virus and naked virus.

 Enveloped virus  Naked virus
In addition to nucleocapsid they contain an outer membrane line structure called the envelope.They contain only the nucleocapsid and lack the envelope.
Virions with envelopes are sensitive to lipid solvents such as ether and Chloroform.Naked virions are not affected by the lipid solvents.


The storage products of fungi are __________ and __________.

Fungi have the reserve food material in the form of Glycogen and oil.


Fungi do not possess chlorophyll. Hence they are incapable of photosynthesis.So, they depend on either living organisms or non-living things. Name the two types of modes of nutrition in fungi.

The two types of modes of nutrition in fungi are
1. Saprophytic- In this then fungi obtain nutrition from dead and decaying organic matter with the help of enzymes.
2. Parasitic- In this the fungi penetrate the body of the organisms with the help of hyphae to obtain nutrition. Such fungi cause diseases in plants and animals,


Viruses can undergo mutation. What does this signify?

Viruses contain genetic material enclosed in a protein coat, many a times when they replicate in the host cell the genetic material using host machinery their genetic material is susceptible to mutation. This may result in the modification of viral genetic material, leading to their evolution in to a new pathogenetic entity.


________ isolated first virus in crystalline form.

In 1935, Wendell Stanley was awarded the Nobel prize for isolating the tobacco mosaic virus in the crystalline form. Wendell Stanley isolated the first virus in crystalline form.


Name the three domains according to the modern classification proposed by C.Woese, O.Kandler and M.C.Wheelis.

The three domains in the taxonomic classification is Archaea, Bacteria and Eukarya.


Describe the structure of a typical protist.

Protists are miscroscopic organisms. Cell structure is eukaryotic. It is surrounded by plasmalemma (cell membrane). There may be an outer covering of pellicle, cuticle, shell or cellulose wall. It contains organelles like mitochondria, Golgi complex, endoplasmic reticulum, 80S ribosomes, etc. Centrioles occur in a number of types. Photosynthetic forms contain chloroplasts with internal thylakoids. Cilia and flagella occur in a number of forms. They have typical 9+2 fibrils. Nucleus has typical structure- porous nuclear envelope, chromatin, nucleolus and nucleoplasm. Many forms have more than one similar or dissimilar nuclei.

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What do you mean by archaebacteria?

  • Archaebacteria are a type of single-cell organisms. These are prokaryotes. There are three major groups of Archaebacteria, namely methanogens, halophiles, and thermoacidophiles. 


Which protist causes Leucorrhoea?

Trichomonas vaginalis is a protist which inhabits vagina of women and causes the disease leucorrhoea. The disease is characterised by burning sensation, itching and frothy discharge. Transmission is by coitus (sexual intercourse).


What is organisation ?

Organisation is the arrangement of smaller components of any structure, system or situation into larger ones and the larger ones into still larger ones in a hierarchy, where components of each level coordinate with one another towards a common goal.


Name a moneran which shows pendulum like movements.

Oscillatoria shows pendulum like movement. It is a genus of filamentous cyanobacterium. The tip of the trichome shows pendulum like movement.


Who proposed the term Protista?

The term protista was proposed by Ernst Haeckel. He proposed the kingdom protista. Phylogenetically, the kingdom protista acts as a connecting link between the prokaryotic kingdom- Monera on one hand and the complex multicellular kingdoms- Fungi, Plantae and Animalia on the other hand. Protists are regarded as ancestors of all multicellular eukaryotic organisms.


What is heterothalism? Give its importance.

Heterothallism is production two types of thallus/hyphae in fungi, designated as the + and the - type. These hyphae undergo nuclear fusion to produce zygote. 
Example- Rhizopus


In what respect do you consider bacteria as simple organisms?

Bacteria are prokaryotic organisms and are unicellular which don't have a membrane around the nucleus and they also lack the presence of mitochondria and chloroplast.


Name the protein coat which surrounds the nucleic acid core of a virus. 

Capsid is the protein coat that surrounds the nucleic acid in virus.


Name the three kingdoms of Archaea.

  • According to Carl Woese’s classification system the living world is divided into three domains: Eukarya, Archaea and Bacteria.
  • Domain Archaea is further divided into three kingdoms of: Methanogens (methane producing), Halophiles (salt lovers) and Thermoacidophiles (heat and salt lover).


Classification reflects phylogeny when the hierarchy of groups reflects their ...........

Classification is the process by which anything is grouped into convenient categories based on some easily observable characters.
  • Phylogenetic system of classification
It is based on the evolutionary relationship between a group of individuals.
So, the correct option is 'Evolutionary relationship'.


What is the the basic unit of classification?

Species is the basic unit of classification. Species are a group of organisms that are morphologically similar and can interbreed.
So, the correct answer is 'species'


How would you distinguish Archaea from Eubacteria?

Archea contains pseudomurein in their cell wall, Eubacteria contains Murein or peptidoglycan
Proteins associated with DNA in Archea are Histones, in Eubacteria they are Polyamines
Archea can be found in extreme habitats, Eubacteria are not
Example of Archea: Metanogens, : Example of Eubacteria : Lactobacillus, Vibrio cholerae


Enumerate the criteria used by Whittaker (1969) for classification of organisms.

The criteria used by Whittaker for classification includes Complexity of cell structure i.e prokaryotes or eukaryotes, complexity of the organisms body i.e unicellular or multicellular, and mode of nutrition.


What type of organisms were included in Kingdom Animalia by Whittaker (1969) in his Five Kingdom system of classification?

The animal kingdom of Whittaker classification included the following characteristics,
All organisms are multicellular, eukaryotes with heterotrophic mode of nutrition


Whittaker classified organisms on the basis of:

In 1969, Robert Whittaker proposed the five kingdom classification. In his proposed classification, he divided organisms into five kingdoms: Monera, Protista, Fungi, Plantae, and Animalia. These groups were formed on the basis of their cell structure, mode, and source of nutrition, body organization, reproduction, and inter-relationships between organisms.


Match the term to these definitions.
UNDERSTANDING THE TERMS
Taxonomy, Classification, Phylogeny, Phylogenetic tree, Taxon, Homology, Analogy, Cladistics, Nomendature, Archaea, Fungi, Protista
.......... characterised  by possessing cell walls without peptidoglycans.

Archae is the most primitive type of bacteria. Its cell wall does not possess peptidoglycans and can survive in extreme conditions.


Short / Long answer type questions.
Describe in brief the economic importance of bacteria.

The economic importance of a bacteria which is prokaryote and microscopic organism is:
 1. Beneficial effects of Bacteria: 
A)  Role in agriculture 
a)   Bacteria as Scavenging: Saprophytic bacteria obtain food from organic remains such as animal excreta, fallen leaves, meat etc. They decompose these substances by the action of digestive enzymes aerobically or anaerobically (known as fermentation). Thus they help in sanitation of nature, so also known as scavengers. E.g. Pseudomonas
) Nitrification: Rhizobium bacteria, living in root nodules of leguminous plant symbiotically, helps in fixing atmospheric nitrogen. Similarly, Nitrosomonas and Nitrococcus convert ammonium salt to nitrites. Nitrites are further changed to nitrates by Nitrobacter and Nitrocystis. It enables plants to uptake nitrogen. 
c) Production of Organic Manure: As stated above, saprophytic bacteria help in breaking of the complex organic substance to simpler forms. Thus, in this process, they help to convert farm refuse, dung and other wastes to manure. 
d) Preparation of Ensilage: Ensilage is preserved cattle fodder prepared by packing freshly chopped fodder sprinkled with molasses. Fermentation activity of bacteria produces lactic acid that acts as a preservative in ensilage.
e) Production of fuel: Bacteria, while converting animal dung and other organic wastes to manure, help in the production of fuel that is a must in gobar gas plant.
f) Disposal of sewage: Bacteria help in disposal of sewage by decomposing it and thus, help in environmental sanitation.
B) Bacteria role in Industry 
a) Dairy Industry: Bacteria such as Streptococcus lactis convert milk sugar lactose into lactic acid that coagulates casein (milk protein). Then, milk is converted into curd, yogurt, cheese etc needed for the industry.
b) Production of Organic Compounds: Fermentation (breakdown of carbohydrate in absence of oxygen) action of various bacteria produces organic compounds like lactic acid (by Lactobacillus), acetic acid (by Acetobacter aceti), acetone (by Clostridium acetabutylicum) etc.
c) Fibre Retting: The action of some bacteria like Clostridium,
Pseudomonas etc. help in fiber retting i.e. separation of stem and leaf fiber of plants from other softer tissue.
d) Curing: The leaves of tea and tobacco, beans of coffee and cocoa are cured off their bitterness with the help of action of certain bacteria such as Bacillus megatherium.
e) Production of Antibiotics: Number of antibacterial and antifungal antibiotics such as Hamycin, Polymyxin, Trichomycin etc are obtained from mycelia bacteria (like Streptomyces). Similarly, Bacillus is used for the production of antibiotics such as Bacitracin, Gramicidin etc
f)  Production of Vitamins: Different kinds of vitamins are produced from bacteria like Riboflavin from Clostridium butylicum, Vitamin B12 from Bacillus megatherium and Vitamin K and B-complex from Escherichia coli.
2. Harmful effects of Bacteria: 
Though bacteria play important role in agriculture, industries and natural sanitation etc, it has the following harmful effects: 
a) Food Spoiling: Saprophytic bacteria always not only help in decomposition of dead matters, but they also cause the rotting of vegetables, fruits, meat, bread etc.
b) Food Poisoning: Bacteria like Staphylococcus aureus cause food poisoning and cause people diarrhea and vomiting.
c) Damaging domestic articles: Spirochete cytophaga deteriorates cotton, leather, and wooden articles.
d) Denitrification: Bacteria such as Thiobacillus and Microbacillusconvert nitrate of the soil to the gaseous nitrogen. This hampers plants very much.
e) Desulphurization: Bacteria such as Desulfovibrio convert soil sulfates into hydrogen sulfide.
f) Cause of Diseases: It is known that over 90% of human diseases and over 10% of plant diseases are caused by bacteria. 



Name the three groups into which Archaebacteria has been categorised.

Archaebacteria is grouped into three Methanogens, Halophiles, Thermoacidophiles.



Methanogens have a unique form of energy metabolism in which .......... is used to reduce......…. to ..........

Methanogens have a unique form of energy metabolism in which $$H_2$$ is used to reduce $$CO_2$$ to methane


Name a disease of human beings caused by prions.

Creutzfeld-Jacob disease.


How does Penicillium reproduce asexually?


  • Penicillium is a saprophytic fungus, com­monly known as blue or green mold.
  • Asexual reproduction in Penicillium takes place by unicellular, uninucleate, non-motile spores, the conidia (spores).
  • The conidiophore is branch formed from the mycelium. Mycelium is the vegetative part consisting a mass of branched thread-like structure called hyphae.
  • After maturation, conidia from the conidiophore detaches from the parent body and are dispersed through wind.
  • On finding suitable substratum, germination takes places leading to the formation of a new septate branched mycelium. This again develops and on maturation release conidia spores and the cycle repeats.

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Name the genus to which baculoviruses belong. Describe their role in integrated pest management programmes.

Baculoviruses belong to the genus Nucleopolyhedrovirus. Baculoviruses are regarded as natural pest management microorganism. They show activity against a wide range of a species-specific pathogen. Most importantly these viruses don't show any negative impact on plants, mammals, fish, bird etc.


Mention the role of Methanobacterium in rumen of cattle

Methanobacterium are also called as methanogens. They are found in the rumen of cattle. In the rumen of cattle, they break down the food eaten by cattle and produce methane gas. This is done by the fermentation process. The methane gas is released in the atmosphere during exhalation.


Give a brief account on the need of classification?

Classification of organisms is of much importance, as it helps in the convenient study of living organisms.
  • It helps in the correct identification of different varieties of living species.
  • It aids in the study of origin and evolution of living species. It also helps in understanding the development of the complexity of living organisms.
  • It helps in understanding the abiotic and biotic relationships of organisms.
  • It helps in the efficient planning for conservation of the endangered species. 


Majority of lichens are made of

Majority of lichens are made of Blue-green algae and ascomycetes.


Give the general characters of viruses.

General characteristics of viruses are:
  • They are ultramicroscopic disease causing organisms.
  • They have no cellular organisation and metabolic machinery.
  • They need host's machinery to make their replicas or copies.
  • They have simple structure and basically composed of nucleic acid wrapped in protein coat.
  • They are obligatory and intracellular parasites. 
  • They are completely inactive outside the host.
  • They are always specific in their action i.e. infect a particular organism or organ.
  • They are neither capable of growth nor division.
  • They can be crystallised and even in crystalline form, their infectivity is retained.
  • They can undergo mutations.


Discuss how the classification system has undergone several changes over a period of time?

The first attempt of classification was made by Aristotle. He classified plants as herbs, shrubs, and trees. Animals, on the other hand, were classified on the basis of presence or absence of red blood cells. This system of classification failed to classify all the known organisms. Therefore, Linnaeus gave a two kingdom system of classification. It consists of kingdom Plantae and kingdom Animalia. However, this system did not differentiate between unicellular and multicellular organisms and between eukaryotes and prokaryotes. Therefore, there were large numbers of organisms that could not be classified under the two kingdoms. So Ernest Haeckel then separated unicellular eukaryotic organisms into separate kingdom named Protista and hence gave three kingdom classification. After that Copeland,separated all prokaryotic organisms into a separate kingdom named Monera and hence Four-Kingdom systems of classification came into existence.
And lastly, a five kingdom system of classification was proposed by R.H. Whittakaer in 1969 to separate achlorophyllous,decomposer organism into a separate kingdom named Fungi. 


Brief about Aristotle's classification?

The Greek scientist, Aristotle was one of the first scientists to organize living things. Taxonomy is the science of how living things are grouped together. 
Aristotle developed the first classification system, which divided all known organisms into two groups i.e. animals and plants.
He used simple morphological characters to classify plants into trees, shrubs, and herbs. He also divided animals into three groups based on their habitats. 
But the classification wasn’t justified. Animals in each group have nothing in common, other than their habitat (except few).


What are thermophiles?

Thermophiles are microorganisms, which are having an optimal growth temperature of 60-1080C. They are isolated from a number of marine and terrestrial geothermally. They are mainly found in hot springs and such extreme habitats. 


Define dueterolichens with examples.

Sterile lichens are that which do not produce spores. The dueterolichens are mostly sterile lichens in which sporocarps are unknown. Imperfect pycnidial stages are known to be produced by a number of asco lichens. Such lichens are usually found growing in soil, rocks, and trees. 
Important genera are Cystocoleus, Lepraria and Lichenothrix.


What were the limitations of five kingdom classification?

  • The limitations of the present five kingdom classification are:-
1) The unicellular algae are kept in kingdom Protista while some algae which are multicellular organisms are kept in the kingdom Plantae. 
  • Similar organisms are not put together.
2) A wide variety of diversity can be seen in the kingdom Protista.
  •  Dissimilar organisms must not be kept in the same group.
3) All organisms other than Monerans shows that they are polyphyletic in origin (derived from more than one common evolutionary ancestor or ancestral group).
4) There is no place for viruses in five kingdom classification.
5) Similar organisms are kept far from each other. 
  • For example, unicellular and multi cellular algae.


State the merits of Whittaker's method of classification.

Explanation:
  • R.H. Whittaker proposed the five kingom classification. His classification includes Kingdom Protista, Kingdom Monera, Kingdom Fungi, Kingdom Plantae and Kindom Animalia.
The merits of Whittaker's Classification are as follows-
  • In Whittaker's method of classification, unicellular and multicellular organisms are kept in different groups.
  • Since fungi don't produce its own food, it is kept in a different group from the plants.
  • The autotrophic organism and heterotrophic organisms are kept in different groups in Whittaker's classification.
  • The unicellular prokaryotes get their own separate group.



Give a brief account on TMV.

TMV stands for 'Tobacco Mosaic Virus' and it was one of the first viruses discovered and purified in the 1800s. It affects only dicotyledonous plants of which tobacco and tomato are mainly affected. When infected by this virus, the plants show a characteristic mottling and discolouration which look like a 'mosaic' and hence, the name. TMV is a simple single-stranded RNA virus enveloped by a protein coat. This coat, in technical terms, is called a 'capsid' and is made up of small subunits called 'capsomeres'. Once inside a plant cell, the capsid sheds away and the nucleic acid directs the plant to produce more viral particles thus disrupting the normal activity of the cell. The virus is mainly transmitted to other plants through the workers' hands, clothing, etc., and therefore is also known as 'mechanical transmission'. Structure of the TMV is seen in the diagram provided. 
1007016_1087539_ans_42a23c557d7a429bbb6fd3746d218cf4.png


What are the different types of lichen based on their external forms?

Based on the external form, the lichens are of five types:
  1. Leprose- In this type the fungal mycelium envelops the algal cells. It appears as powdery mass. For example Lepraria incana.
  2. Crustose- This lichen appears as a thin layer or crust and is wholly or partially embedded within the substratum. For example Rhizocarpon.
  3. Foliose- This lichen is leaf-like in appearance and shows lobes in the thallus. It is attached with the substratum by the help of rhizines. For example Parmelia.
  4. Fruticose- This lichen appears like a shrub and has a well-developed thallus. For example, Usnea.
  5.  Filamentous- In this lichen algal partner is filamentous and fungal partner shows few hyphae. For example, Racodium.


Describe the given picture.
1101747_0148d4b7c9fb49ccb67d2c3abb711b90.png

This is a typical bacterial cell. This is a gram-positive bacteria that is enclosed in a capsule. Cell wall is bound by a capsule and flagella is attached to the cell wall. No distinct nucleus is found in cytoplasm. There is a plasmid in the cell. Food storage structures known as glycogen granules are found in the cytoplasm


Which do you think is a more basic characteristic for classifying organisms?

(a) The place where they live.
(b) The kind of cells they are made of. Why?

  • The kind of cells they are made of is a more basic characteristics for classification of organisms since it gives proper differentiation between them. 
  • The place where they live can often miss guide us as various different kind of organisms live in the same area. For example, a banyan tree and a cat live in the same area but are very distant biologically.
  •  One belongs to the Plant Kingdom whereas the other belongs to an Animal Kingdom.
  • If we see on the basis of their cells, we can properly make out the difference between a plant cell and animal cells and differentiate them into different groups.


Justify that Lichens are pioneer organisms.

Lichens are considered as pioneer organisms because there are the first to colonize bare rocks, mountains, and cliffs. They corrode rocks and accumulate a certain amount of minerals and organic matter. The plants like mosses and grasses appear later in succession, utilizing the first soil formed by lichens. Lichens thus can convert a barren area into one that can support vegetation.


Complete the statements with a proper option from the list given below. 
(mycotoxins, budding, rhizobium)

Toxins of fungal origin are called _______.

Answer: Toxins of fungal origin are called mycotoxins.
 Mycology is the branch of microbiology that deals with the study of fungi (a group of organisms that contains moulds, yeasts and mushrooms) and mycotoxins are poisonous substances produced by fungi. 


As a fungus completes its life cycle on two hosts, it is termed as

A fungus that completes its lifecycle in two hosts is called digenetic


Most abundant bacteria are 

Most abundant bacteria are E.coli, Staphylococcus aureus, Lactobacillus etc.


In the hierarchy of classification, which group will have the smallest number of organisms with a maximum number of characteristics and which group will have the largest number of organism?

Species is the group with smallest no. of organism whereas kingdom is the group that have the largest no. of organism and includes all organisms that shares a set of distinguishing characters.


Who coined term virus?

The term virus was coined by the Dutch microbiologist Martinus Beijerinck. 


Explain bacillus.

Bacillus species are rod-shaped, aerobic or facultatively anaerobic, Gram-positive bacteria. They differ from other bacteria like cocci ( spherical ) or vibrio ( comma ) in shape. 
1063316_1153202_ans_669d51b248be431bb41cff30891ab7ae.jpg


What is the basis for classification?

The basis of classification are as follows: 
• Cell structure
• Mode and source of nutrition
• Body organisation.
Classification makes the study of a wide variety of organisms easier. This helps us in understanding evolutionary history of organisms easily. It helps in providing knowledge about origin and genetic relationship among organisms easily.


'Classification of life forms is closely related to their evolution.' Do you agree with this statement? Comment with an example.

1. Classification of life forms is closely related to their evolution. Living things are identified and categories based on their body design related to their forms and functions. 
2. Accumulation of changes in the body design of recent organisms has given them better chances of survival. However, the body design of recent and older or may be extinct organisms remains the same. 
For example :
An archaeopteryx is considered a connecting link between reptiles and bird. 
Archeoptryx had teeth, claws and long hind legs like reptiles. It has feathered tail, wings and beaks like bird. 
All reptiles and birds are vertebrates which means they possess the vertebral column. 
They are triploblastic (body composed of three embryonic layers) 
Some, changes occured in some reptiles which helped them to evolve as a separate class of bird. 



How nucleopolyhedroviruses are used in these days?

  • The nucleopolyhedrovirus (NPV) belongs to the family of baculoviruses is a virus affecting insects predominantly moths and butterflies. It has been used as a pesticide.
  • Nucleopolyhedrovirus preparations have also been used commercially against pests such as Trichoplusia and the cotton leafworm.
  • Nucleopolyhedrovirus are used in these days for the biological control of insect pests.
  • After ingesting NPV, infected larvae will eat normally for a couple of days before reducing feeding substantially. Diseased larvae typically climb to the top of the plant and die. Shortly after death, the body becomes flaccid and the skin ruptures, releasing millions of infectious virus particles. When many larvae are living close together, they can infect each other and results in complete eradication of pests.


List any $$3$$ characteristic's of fungi.

  1. Fungi are eukaryotic and mostly multicellular organisms.
  2. They are exclusively heterotrophic - either saprophytic or parasitic.
  3. Their cell wall is made of chitin.


Write two precautions you take, while observing Rhizopus in the laboratory.

i) Keep away from mould who is suffering from allergies and asthma.
ii) Do not touch mould with bear hands. If you touch it be sure to thoroughly wash your hands afterwards.


Kingdom Fungi have cell wall, but still it cannot be classified under Plantae? Give any two reason.

  1. They are heterotrophic and lack chlorophyll.
  2. Cell wall is made of chitin and not cellulose
Hence Fungi are not included under Kingdom Plantae.


Write any two places where methanogens can be found.

Methanogens are commonly found in 
  1. Guts of animals
  2. Hydrothermal vents 
  3. Deep layers of marine sediments 
  4.  Wetlands


It is necessary to give scientific names to the organisms. Give scientific reason.

Answer
  • Every organism is given a scientific name to avoid confusion with its local names across the world.
  • Binomial nomenclature is used to give scientific names to the organisms based on the genus and specific epithet it belongs.
  • This way it becomes easy to study and understand organisms on a large scale considering the diversity of organisms we have in nature .


In Rhizopus, tubular thread-like structures bearing sporangia at their tips are called:
A. filaments
B. hyphae
C. Rhizoids
D. roots

Hyphae in fungi are filamentous structures which branch out and spread below the surface of a substratum like bread. During their life cycle a hyphae may rise erect above the surface, with it's content at the tip forming a bulge. This bulge forms the sporangium. Spores are formed in the sporangium and is a mode of asexual reproduction.
Example, Rhizopus or bread mould


Fungi do not contain _____.

Fungi do not contain Chlorophyll.
They exhibit a saprophytic or parasitic mode of nutrition.


Explain the criteria for grouping of organisms into five major kingdoms.

(i) Presence or absence of a well defined nucleus: This divided all organisms into prokaryotes that contains genetic material in the form of nucleoid and eukaryotes with genetic material enclosed within the nuclear membrane.

(ii) Organisms are single celled or multicellular: All single celled eukaryotic organisms were grouped under Protista, while multicellular eukaryotes were further classified into three kingdoms.

(iii) Presence or absence of cell wall: Multicellular eukaryotes with cell wall were placed under Plantae and Fungi while those without cell wall were placed under animalia.
(iv) Mode of nutrition:  Multicellular photosynthetic eukaryotes were placed in plantae, multicellular, eukaryotic saprophytes were placed in Fungi and multicellular, eukaryotic holozoics were placed in animalia.


Pick incorrect statement/s:
A. Protista includes unicellular eukaryotic organisms
B. Whittaker considered cell structure, mode and source of nutrition for classifying the organisms into five kingdoms
C. Monerans have well-defined nucleus

Kingdom Monera includes all  prokaryotes. They have a primitive nucleus, that is, without a nuclear envelope, 70S  type of Ribsomes and have no double membrane- bound organelles
Example - Bacteria
So, statement C is incorrect.


A fungus ______ can be seen without microscope.

A fungus mushroom can be seen without microscope.

Mushrooms are reproductive structures of Basidiomycetes. Some groups  of  mushrooms are edible.


Basic smallest unit of classification is __________

Basic smallest unit of classification is Species
Species are a group of organisms which are morphologically similar and can interbreed to produce fertile progeny.


What observable features in Trypanosoma would make you classify it under kingdom Protista? 

$$\textbf{Explanation:}$$

$$\bullet$$ $$Trypanosoma$$ is an unicellular eukaryotic organism with a well defined nucleus and membrane bound organelles.

$$\bullet$$ It is a heterotrophic, parasitic and flagellated protozoan.

$$\bullet$$ It causes a disease 'Sleeping sickness'. It causes infection through a vector, tsetse fly. Hence, it is parasite in tsetse fly and causes infections in humans.

$$\bullet$$ As $$Trypanosoma$$ shows above mentioned features it belongs to kingdom Protista.



Explain Symbiosis in Lichens?

In Lichens, the plant body has alga and fungus, living together and deriving benefit from one another. The fungus provides shelter to alga and also maintain the humidity inside the lichen body, necessary for the alga for the process of photosynthesis. In return, the alga provides the food material, prepared during photosynthesis to the fungus. This kind of association is called symbiosis or mutualism.



In the five-kingdom system of Whittaker, how many kingdoms are eukaryotes?

$$\textbf{Explanation:}$$

$$\bullet$$ R.H. Whittaker (1969) proposed the five kingdom classification.

 $$\bullet$$These kingdoms are Monera, Protista Fungi, Plantae and Animalia. 

 $$\bullet$$ Out of these five, only one kingdom- Monera includes prokaryotes.

 $$\bullet$$ Rest four kingdoms- Protista, Fungi, Plantae and Animalia are eukaryotes.


Who am I? 
I live on dead and decaying organic matter.

  • The organisms living on the decaying matter are decomposers.
  • They break down dead and decaying animals and plants for nutrients and energy. 
  • Examples of decomposers are fungi and soil bacteria.




Explain the structure of virus? Draw a labelled diagram of Bactereriophage

Viruses are non-cellular structures composed of a protein shell called capsid and a core of nucleic acids. They are so minute that they can even pass, through the microfilters and can be stored in the form of crystals. They are infectious agents, which can reproduce only in another living cell that acts as a host. They are parasitic for the purpose of the replication of their genetic material as they, themselves, do not possess the replication enzymes, etc. 
Viruses may contain DNA or RNA but, never both types of nucleic acids. Those which contain RNA as the genetic material are called retroviruses or riboviruses and there are about 400 types of RNA viruses. Those which contain DNA are called deoxy viruses. This genetic material is also called viral chromosome or viral genome which is always in the form of a small molecule. Those viruses which parasitise on bacteria are termed as bacteriophages. 
2035486_1838347_ans_64bdb5bf7adc43a181bae56b41adb772.png


Write short notes on:
Lichen.

1. Lichens occur in certain specific habitats that are least polluted. They grow on rocks, leaves, the bark of trees and forest floor. 
2. Lichen can be called a compound plant because an alga and a fungus live together in its thallus in mutual partnership and each gets to benefit from one another. 
3. Fungus provides shelter to the alga and maintains humidity inside the thallus of lichen. Moisture is generally absorbed from the atmosphere. Algae manufacture the starch, which is used as food by the fungus. 
4. Lichen thallus may be flat, leaf-like or branched and larger in size. 
and are classified as Crustose lichen, Foliose lichen and fruticose lichen respectively
1772642_1831918_ans_4b0085a0081242ab8c2c9c227c412a00.png


What are viruses? Why do they not show any characteristics of life? 

Viruses are very small particles with nucleic acid, that is, either DNA or RNA enclosed within a protein coat called capsid. These particles do not contain cytoplasm. cell organelles or enzymes (cellular machinery) for independent functioning. Hence, they require a host to multiply and if not they are similar to any other non-living particle. Thus, do not show any characteristics of life.


Who proposed the five kingdom classification?

The five kingdom classification was proposed by Robert H. Whittaker in 1969. The five kingdoms are Monera, Protista, Fungi, plantae and Animalia.


Following are a few organisms
(a) lichen (b) mosses (c) mango tree (d) cactus
Which among the above can grow on stones; and also help in formation of soil? Write the mode of their action for making soil.

Lichens and Mosses (a) and (b). Lichens and mosses release certain extracellular enzymes which break down the stones resulting in the formation of soil.
Any habitatat is first colonized by Lichens followed by Bryophytes. Their decay and decomposition leads to increase in organic content of the soil which  paves way for other forms of vegetation. 


If there are two pathogenic viruses, one with DNA and other with RNA, which would mutate faster? And Why?

The pathogenic virus with RNA will mutate faster. RNA replication is more prone to errors than DNA replication. Hence, RNA offers more chances of mutation than DNA. In other words, DNA is more stable than RNA. Hence, a virus with RNA would mutate faster than a virus with DNA.


Give an example of a rod-shaped virus. 

Tobacco Mosaic Virus (TMV) is an example of a rod shaped virus.


What is the common method of reproduction in bacteria?

Bacteria reproduces through asexual means such as amitosis or binary fission.


What for Nucleopolyhydro viruses are being used now-a-days? 

Nucleopolyhydro viruses are used for controlling pests and other arthropods in farms. These are narrow-spectrum viruses and do not harm plants, cattle, and humans, or even on non-target insects.  


Long Answer.

Lichen is usually cited as an example of 'symbiosis' in plants where an algal and a fungal species live together for their mutual benefit. Which of the following will happen if algal and fungal partners are separated from each other?
(a) Both will survive and grow normally and independently from each other.
(b) Both will die
(c) Algal component will survive while the fungal component will die.
(d) The fungal component will survive while the algal partner will die.
Based on your answer how do you justify this association as symbiosis

Option 'b' is the correct option, i.e. both will die.
Symbiosis: This is a symbiotic association that can be defined as a relationship between two organisms in which both the organism get benefitted from each other. There can be many examples of symbiotic relationships in which the removal of one may not result in the death of another partner. For example; in the case of a symbiotic relationship between a bird and a buffalo, the worms and insects on buffalo's back are not the only sources of food for the bird. Similarly, there can be some other ways for the buffalo to get rid of those pests.
But in case of lichen; both the fungal and algal components depend on each other for their basic needs. In this case, the alga is the only source of food for the fungal components. Similarly, the fungus is the only source of water and minerals for the alga. They have no alternative means to fulfill their need and hence in case of the removal of any one partner, another partner would die.
Since it is a relationship of mutual benefit hence it will still be called symbiosis.


Identify and state the type of reproduction represented in the above figure.
1911529_12cf6efc0b95446c94f0f828c845f066.png

The above diagram show spore formation, a mode of asexual reproduction in fungi. Asexual spores are formed after mitosis without the involvement of meiosis. Fungi produce an enormous variety of asexual spores. 
Sporangiospores are formed endogenously in a sporangium via cytoplasmic cleavage in the zygomycetes. Motile, flagellated spores of the chytridiomycetes are called zoospores and the term conidium is used for an asexual, nonmotile  spores in Ascomycetes.


In the following figure, explain how new fungal colonies of Mucor are formed:
1911520_533ea439abc64b1382931bf59275befe.png

1. Fungi like Mucor have filamentous body.
2. They produce Sporangia, that contain spores.
3. Once the sporangia are mature they burst and release the spores.
4. Spores germinate in moist and warm places and new fungi are formed.


Kingdom Monera includes the most ..........1.........., the ..........2.........., the simplest and the most plentiful ..........3........... These organisms are most ..........4........... They were the first ..........5.......... of the earth, and they still ..........6.......... to flourish. Carl Woese (1994) has ..........7.......... kingdom Monera into Archaebacteria and ..........8........... These ..........9.......... are mostly unicellular. The ...........10........... are, however, ..........11.......... They do not have a ..........12.......... nucleus. The genetic material is a ..........13.......... double-stranded, ..........14.......... (Deoxyribonucleic acid) not enclosed by a ..........15.......... Such organisms which do not have a ..........16.......... are called prokaryotic.

1. ancient, 2. smallest, 3. prokaryotes, 4. primitive, I 5. inhabitants, 6. continue, 7, divided, 8. Eubacteria, 9. organisms, 10. cyanobacteria, 11. filamentous, 12. definite, 13. circular, 14. helical DNA, 15. nuclear envelope, 16. definite nucleus.


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

Explanation:
  • The first attempt of classification, made by Aristotle, classified plants as herbs, shrubs, and trees. 
  • Linnaeus gave a two kingdom system of classification consisting of kingdom Plantae and kingdom Animalia.
  • Ernest Haeckel separated unicellular eukaryotic organisms into the kingdom Protista and therefore gave three kingdom classification.
  • Copeland separated all prokaryotic organisms into kingdom Monera and therefore a four-kingdom system of classification came into existence.
  • Lastly, a five kingdom system of classification was proposed by R.H. Whittaker. 
  • The five kingdoms are monera, Protista, Fungi, Plantae and Animalia.


Define nucleocapsid.

All viruses contain nucleic acid surrounded by a protein capsid known as the nucleocapsid. Protein coat or the capsid which function as a shield to safeguard the genome of viruses from nucleases activity and also during infection attaches the virion to the receptors which are specific to host cells. Capsids are single or multilayer protein shells and comprise one or a few structural protein species. The proteins which are used to build the capsid or protein coat are called capsomeres. The nucleic acid with capsid forms the nucleocapsid.



Write a note on "significance of viruses".

Viruses nowadays use as a tool in genetic engineering laboratories to target and kill cancer cells, to treat a variety of genetic diseases as a gene therapy tools, and also in vaccine delivery. Viruses are necessary microbial predators that influence global biogeochemical cycles and drive microbial evolution, although their effect is frequently underappreciated.



Make an outline of the classification. What are the advantages and disadvantage of this classification?

Five kingdom classification was given by R. H. Whittaker. The five kingdoms are Monera, Protista, Fungi, Plantae, and Animalia. 
Advantages:
1. Prokaryotes have got separate place as kingdom Monera. 
2. Unicellular and multicellular organisms are kept separate. 
3. Fungi are separated from plants and given a special kingdom. 
4. Autotrophs and heterotrophs are placed in separate groups. 
5. Five kingdom classification is more natural than two kingdom classification. It's classification is based on bio composition and mode of nutrition. 
Disadvantages: 1. Unicellular algae are kept in protista and multicellular algae in plantae. Similar organisms are kept far from each other. 
2. Dissimilar organisms are placed under same kingdom. Example. Protista. 
3. No place is given for viruses in this classification. 


Highlight the criteria used for five kingdom system of classification.

Robert H. Whittaker in 1969 gave the five kingdom system of classification. These five kingdoms are- Monera, Protista, Fungi, Plantae, and Animalia. This classification was based on following factors-

1. Structure of cells: Living organisms can be divided into two main categories on the basis of cell structure-
a) Prokaryotic ( cells lacking well-organized nucleus and other membrane-bound organelles)
b) Eukaryotes ( cells having well-organized nucleus and other organelles)

2. Complexity of organism-
a) Unicellular (organisms having single cell)
b) Multicellular ( organisms consisting of more than one cell in their body)

3. Mode of nutrition: Organisms were divided into -
a) Autotrophic i.e. that can make their own food with the help of light (phototrophs) or with the help of chemical compounds (chemotrophs).
b) Hetrotrophic i.e that can not make their own food and depend on plants or other animals for food. 

4. Phylogenetic relationship- Phylogeny means the evolutionary history of an organism. This feature shows the direction of evolution of organisms.

5. Ecological role of organisms was also considered and the organisms were divided into producers, consumers, and decomposers.


Discuss the types of reproduction in Kingdom Mycota with examples

  • Kingdom Mycota includes fungi. Reproduction in Fungi can be:-
1) Vegetative reproduction:-
a) Fragmentation- Mycelium  may break accidentally or due to decay into 2 or more parts.
  • Each parts develops into complete mycelium.
  • Eg- mushrooms.
b) Budding-  Fungus protrudes out at one end.
  • The protrusion grows out into a bud and gets separated to form new individual.
  • Eg- yeast.
c) Fission- It occurs in unicellular forms where cell divides to produce 2 daughter cells.
  • Eg- yeast.
2) Asexual reproduction:-
  • Endogenous:- These spores are formed internally within sac by the division of protoplasm. 
  • E.g. Sporangiospores.  
i) Sporangiospores:- A motile spore produced in a sac or sporangium and are unicellular. 
  • These spores are liberated by breaking the wall of sporangium. 
ii) Aplanospore: A non motile spore produced in the sporangium is knows as Aplanospore.
b. Exogenous:- These spores are borne externally on sporophores.
  • E. g. Conidia, Oidia.
i) Conidia:- These spores are produced on sepecialized hyphae or stock. i.e. conidiphore.
  • Conidia may be uni or multicellular.
  • E.g. Alternaria, Helminthosporium
ii) Oidia:- They are  produced asexually in chains on the stalk called as oidiophore.
  •  E.g. Oidia in powdery mildew.
3) Sexual reproduction:-
i) Oospores:
  • It is the result of union between female gametes i.e. Oogonium and male gametes i.e. Antheridium.
  • These spores can resist the adverse conditions. 
  • E.g. Fungi of sub-division Mastigomycotian. 
ii) Ascospores:
  • It is a result of union between female gametes. I.e. Ascogonium and male gamete. i.e. Antheridium.  
  • E.g. Fungi of sub-division Ascomycotina.
iii) Basidiospores:
  • These are the sexual spores produced on club shaped structure known as basidium.
  • E.g. Fungi of sub-division Basidiomycotina.


Complete the chart.
1100912_0341b19df49d41eca0240705a51d5bbd.PNG

The blanks have the following answer, from the top to bottom order:
Eukaryotic
Monera
Protista
Without cell wall
Heterotrophic

Monera are prokaryotic
Protista is a Unicellular eukaryotic kingdom
Animalia do not have a cell wall
Fungi are heterotrophic and they have a cell wall.


Sporangiospores are formed in sporangium. The fungal filament on which sporangium is formed is called as

Answer: Sporangiophore.
Explanation :
  • The reproductive structure forms on the stem and contains haploid nuclei and living substances. 
  • Spores square measure fashioned within the stem by encasing every haploid nucleus and living substances in a passing powerful outer membrane throughout agamogenesis, these spores are dispersed via wind and germinate into haploid hyphae. 
  •  The plant structure makes up the plant structure, or uniform body, of typical plant life. 
    • Hence, the plant filament on that reproductive structure is made is named Sporangiophore.



    Class 11 Medical Biology Extra Questions