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Page No 6:
Question 1:
All eukaryotic unicellular organisms belong to
a. Monera
b. Protista
c. Fungi
d. Bacteria
Answer:
All eukaryotic unicellular organisms belongs to Protista.The term protista, meaning "the first of all or primordial" was introduced in 1866 by German scientist Ernst Haeckel. He suggested Protista as a third taxonomic kingdom, in addition to Plantae and Animalia.Protista are eukaryotes, which means their cells have a nucleus and other membrane-bound organelles.It includes Chrysophytes, Dinoflagellates, Euglenoids, Slime moulds, and Protozoans.
Hence, the correct answer is option b.
Page No 6:
Question 2:
The five kingdom classification was proposed by
a. R.H. Whittaker
b. C.Linnaeus
c. A. Roxberg
d. Virchow
Answer:
R.H.Whitaker proposed that organisms should be broadly divided into 5 kingdoms -
a)Kingdom Monera
b)Kingdom Protista
c)Kingdom Fungi
d)Kingdom Plantae
e)Kingdom Animalia
​
It is based on certain characteristics like the structure of the cell, mode of nutrition, the source of nutrition, interrelationship, body organization, and reproduction.
Hence, the correct answer is option b.
Page No 6:
Question 3:
Organisms living in salty areas are called as
a. Methanogens
b. Halophiles
c. Heliophytes
d. Thermoacidophiles
Answer:
Halophiles are salt loving bacteria as Halo means salt and philes means loving. They are a type of extermophilic organism. The name comes from the Greek word for "salt-loving". While most halophiles are classified into the Archae domain. The high concentration of NaCl in halophilic environment limits the availability of oxygen for respiration. Halophiles are chemoheterotrophs, using light for energy and methane as a carbon source under aerobic or anaerobic conditions.
Hence, the correct answer is option b.
Page No 6:
Question 4:
Naked cytoplasm, multinucleated and saprophytic are the characteristics of
a. Monera
b. Protista
c. Fungi
d. Slime molds
Answer:
Slime molds are multinucleated saprophytic with naked protoplasm called Plasmodium. There are two types of slime molds -the cellular slime molds are composed of single amoeboid cells during their vegetative stage e.g. Dictyostelium, whereas the vegetative acellular slime molds are made up of plasmodia, amorphic masses of protoplasm.e.g.Physarella
Hence, the correct answer is option D.
Page No 6:
Question 5:
An association between roots of higher plants and fungi is called
a. Lichen
b. Fern
c. Mycorrhiza
d. BGA
Answer:
Hence, the correct answer is option c.
Page No 7:
Question 6:
A dikaryon is formed when
a. Meiosis is arrested
b. The two haploid cells do not fuse immediately
c. Cytoplasm does not fuse
d. None of the above
Answer:
Dikaryon is characterized by the presence of two nuclei in each cell. It is a unique character found in ascomycetes and basidiomycetes, where there is an intervening (n + n) phase, before the fusion of two haploid cells.
Hence, the correct answer is option b.
Page No 7:
Question 7:
Contagium vivum fluidum was proposed by
a. D.J. Ivanowsky
b. M.W. Beijerinek
c. Stanley
d. Robert Hooke
Answer:
Hence, the correct answer is option b.
Page No 7:
Question 8:
Associations between Mycobiont and Phycobiont are found in
a. Mycorrhiza
b. Root
c. Lichens
d. BGA
Answer:
Hence, the correct answer is option c.
Page No 7:
Question 9:
Difference between Virus and Viroid is
a. Absence of protein coat in viroid but present in virus
b. Presence of low molecular weight RNA in virus but absent in viroid
c. Both a and b
d. None of the above
Answer:
The virus is a small infectious agent that replicates only inside the living cell of an organism. It consists of genetic material, a protein coat, and an envelope. Viroids are the smallest infectious pathogens that are composed of a short strand of circular, single-stranded RNA that has no protein coat.
Hence, the correct answer is option a.
Page No 7:
Question 10:
With respect to fungal sexual cycle, choose the correct sequence of events
a. Karyogamy, Plasmogamy and Meiosis
b. Meiosis, Plasmogamy and Karyogamy
c. Plasmogamy, Karyogamy and Meiosis
d. Meiosis, Karyogamy and Plasmogamy
Answer:
The events in sexual phase of fungi are:
1.Plasmogamy-It involves the fusion of protoplasm of two hyphae or two gametes or two sex cells.
2.Karyogamy-It involves the fusion of two nuclei to form the diploid nucleus and thus the zygote. In the Acomycetes and Basidiomycetes an intervening phase called Dikaryon phase (n+n) which then fuses to form zygote.
3.Meiosis-The zygote undergoes meiosis to give rise to haploid spores.
Hence, the correct answer is Option C.
Page No 7:
Question 11:
Viruses are non-cellular organisms but replicate themselves once they infect the host cell. To which of the following kingdom do viruses belong to?
a. Monera
b. Protista
c. Fungi
d. None of the above
Answer:
Viruses are considered as borderline between living and non-living things. It lacks cellular machinery and hence uses the host cell to multiply.
So, no kingdom has been specified for them.
Hence, the correct answer is option d.
Page No 8:
Question 12:
Members of phycomycetes are found in
i. Aquatic habitats
ii. On decaying wood
iii. Moist and damp places
iv. As obligate parasites on plants
Choose from the following options
a. None of the above
b. i and iv
c. ii and iii
d. All of the above
Answer:
Phycomycetes are the obligate parasites on plants and on decaying wood, that belong to kingdom fungi. They live in aquatic habitats, moist and damp places.
Hence, the correct answer is option d.
Page No 8:
Question 1:
What is the principle underlying the use of cyanobacteria in agricultural fields for crop improvement?
Answer:
Cyanobacteria are autotrophic bacteria. Many species of cyanobacteria like Anabaena, Nostoc, etc. can carry out nitrogen fixation, in a specialized cell called heterocyst. They also add organic matter to the soil. Hence, they are used in agricultural fields for crop improvement.
Page No 8:
Question 2:
Suppose you accidentally find an old preserved permanent slide without a label. In your effort to identify it, you place the slide under microscope and observe the following features :-
a. Unicellular
b. Well defined nucleus
c. Biflagellate–one flagellum lying longitudinally and the other transversely.
What would you identify it as? Can you name the kingdom it belongs to?
Answer:
Page No 8:
Question 3:
How is the five–kingdom classification advantageous over the two kingdom classification?
Answer:
The five–kingdom classification is advantageous over the two kingdom classification in following ways:
2.Two kingdom classification did not distinguish between the unicellular and multicellular where as in five kingdom classification all unicellular eukaryotes are kept in Kingdom Protista.
Page No 8:
Question 4:
Polluted water bodies have usually very high abundance of plants like Nostoc and Oscillitoria. Give reasons.
Answer:
Page No 8:
Question 5:
Are chemosynthetic bacteria-autotrophic or heterotrophic?
Answer:
Chemosynthetic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production. As they are able to manufacture organic food from inorganic raw material with the help of energy derived from exergonic chemical reaction,chemosynthetic bacteria is an autotrophic bacteria e.g. Nitrifying bacteria,Iron bacteria and sulphur oxidising bacteria.
Page No 8:
Question 6:
The common name of pea is simpler than its botanical (scientific) name Pisum sativum. Why then is the simpler common name not used instead of the complex scientific/ botanical name in biology?
Answer:
The common name of Pisum Sativum is pea in English, similarly there are different local names in different languages and places. This resulted in confusion and so, it was important to standardize the name so that the same name can be used all over the world.
Page No 8:
Question 7:
A virus is considered as a living organism and an obligate parasite when inside a host cell. But virus is not classified along with bacteria or fungi. What are the characters of virus that are similar to non-living objects?
Answer:
Virus is an obligate parasite.The characters of virus that are similar to non living objects are-
1.Absence of protoplast
2.Crystalline nature
3.Inability to live independent of a living cell
Page No 8:
Question 8:
In the five kingdom system of Whittaker, how many kingdoms are eukaryotes?
Answer:
In a five kingdom classification of Whittaker, four kingdoms are eukaryotes.They are
1. Kingdom Protista
2. Kingdom Fungi
3. Kingdom Plantae
4. Kingdom Animalia
Page No 9:
Question 1:
Diatoms are also called as ‘pearls of ocean’, why? What is diatomaceous earth?
Answer:
Diatoms are majorly phytoplanktons and are the unique organisms, because of their distinctive cell walls. These walls are embedded with indestructible silica. It shows sculpturing and ornamentation and so, diatoms are also called as ‘Pearls of Ocean’. They left behind large amount of cell wall deposits in their habitat which accumulated over billions of years is referred to as ‘diatomaceous earth’, which is used in polishing, filtration of oils and syrups. They are the chief ‘producers’ in the oceans.
Page No 9:
Question 2:
There is a myth that immediately after heavy rains in forest, mushrooms appear in large number and make a very large ring or circle, which may be several metres in diameter. These are called as ‘Fairy rings’. Can you explain this myth of fairy rings in biological terms?
Answer:
Fairy ring is a naturally occurring circular ring of mushrooms on a lawn or other location. A fairy ring starts when the mycelium(spawn) of a mushroom falls in a favourable spot and sends out a subterranean network of fine, tubular threads called hyphae. The hyphae grow out from the spore evenly in all directions, forming a circular mat of underground hyphal threads. The mushrooms that grow up from this circular underground mat form a similar pattern above ground. Gradually the underground mycelium at the centre of the circle dies out. Its living outer edges, however, keep growing year by year, and hence the diameter of the ring gradually increases.This is called fairy ring especially in Europe.
Page No 9:
Question 3:
Neurospora - an ascomycetes fungus has been used as a biological tool to understand the mechanism of plant genetics much in the same way as Drosophila has been used to study animal genetics. What makes Neurospora so important as a genetic tool?
Answer:
Neurospora is used as an important genetic tool in plant genetics, because of following reasons:
1.They can survive on minimum media.
2.Easy to grow
3.Has a haploid life cycle
4.Reproduce quickly
Page No 9:
Question 4:
Cyanobacteria and heterotrophic bacteria have been clubbed together in Eubacteria of kingdom Monera as per the “Five Kingdom Classification” even though the two are vastly different from each other. Is this grouping of the two types of taxa in the same kingdom justified? If so, why?
Answer:
According to Five Kingdom classification, all prokaryotes are kept under, "Kingdom Monera". Both cyanobacteria and heterotrophic bacteria have naked nucleus. They do not have well developed nucleus and have 70S ribosomes. The mode of nutrition is the major difference between cyanobacteria and heterotrophic bacteria. So, this classification is justified.
Page No 9:
Question 5:
At a stage of their cycle, ascomycetes fungi produce the fruiting bodies like apothecium, perithecium or cleistothecium. How are these three types of fruiting bodies different from each other?
Answer:
Page No 9:
Question 6:
What observable features in Trypanosoma would make you classify it under kingdom Protista?
Answer:
Trypanosoma is classified under Kingdom Protista because it is a unicellular eukaryote.It has a well organised nucleus with nuclear envelope, prominent nucleolus.It also has 80S ribosomes and flagellum for locomotion with 9+2 arrangement.
Page No 9:
Question 7:
Fungi are cosmopolitan. Write the role of fungi in your daily life.
Answer:
- The majority of grasses and trees require a mycorrhizal relationship with fungi to survive.
- Yeasts have been used for thousands of years in the production of beer, wine, and bread.
- Fungi naturally produce antibiotics to kill or inhibit the growth of bacteria, limiting their competition in the natural environment.
- Many valuable drugs isolated from fungi include the immunosuppressant drug cyclosporine (which reduces the risk of rejection after organ transplant), the precursors of steroid hormones, and ergot alkaloids used to stop bleeding.
- Some fungi attack insects and, therefore, can be used as natural pesticides.
Page No 9:
Question 1:
Algae are known to reproduce asexually by variety of spores under different environmental conditions. Name these spores and the conditions under which they are produced.
Answer:
2. Aplanospores: The aplanospores develop in unfavourable conditions. They are non-motile spores.
4. Akinetes (Arthrospores): They are resting spores produced in unfavourable conditions.
5. Statospores: They are also known as resting spores, endospores or cysts during the unfavourable condition. They act as perennating bodies.
6. Palmella stage: In the condition of drought, the successive generations of divided cells are gelatinized and develops a thick mucilaginous envelope.
Page No 9:
Question 2:
Apart from chlorophyll, algae have several other pigments in their chloroplast. What pigments are found in blue-green, red and brown algae that are responsible for their characteristic colours?
Answer:
- Green algae- Green algae have chloroplasts that contain chlorophyll a and b, giving them a bright green color, as well as the accessory pigments beta carotene (red-orange) and xanthophylls (yellow) in stacked thylakoids.
- Brown algae- The brown colour of these algae results from the dominance of the xanthophyll pigment called fucoxanthin, which masks the other pigments, Chlorophyll, and c.
- Red algae- Red algae, however, contain a variety of pigments, including chlorophyll a, chlorophyll d, phycoerythrin, phycocyanin, carotenes, lutein, and zeaxanthin. The most important pigment is phycoerythrin which provides these algae with their red pigmentation by reflecting red light and absorbing blue light.
Page No 9:
Question 3:
Make a list of algae and fungi that have commercial value as source of food, chemicals, medicines and fodder.
Answer:
The economic importance of algae:
- Algae, Chlamydomonas reinhardtii, can be cultivated for hydrogen generation.
- Algae is a complete protein containing important amino acids that are involved in metabolic processes such as enzyme and energy production.
- Single cell protein like Chlorella and Spirulina are used as food by space traveller.
- Chondrus crispus or "carrageen"is a good stabilizer in milk products and used in lotions for skin.
- Laminaria, Sargassum, Porphyra species are used as fodder.
- Algae can be used as sugar and also as natural pigments instead of coloring agents and chemical dyes.
- Gracilaria, Gelidium are used to obtained agar,which is used to make jellies and icecreams.
- Laminaria and Fucus are the source of iodine, Polysiphonia is the source of bromine and Macrocystis is the source of potash.
- Fungi decompose the dead animals and plants and change them into humus which reduces the chance of soil erosion. It also increases the water holding capacity of soil.
- They are important part of lichens which plays an important role in biological succession.
- Lichens are also involved in biological nitrogen fixation.
- Mycorrhizae is an association between fungi and roots of higher plants. It absorbs water and minerals and transports them to plant. Thus help the plants can survive in arid conditions.
- Some fungi like morels and truffles are edible and very delicious.
- Some fungi are used as insecticide,as they kill the insects. For example, fungi are used to kill the wheat bulb flies in USA.
- Some fungi like Gibberella are source of plant hormones, gibberellin.
Page No 9:
Question 4:
‘Peat’ is an important source of domestic fuel in several countries. How is ‘peat’ formed in nature?
Answer:
As this plant material decomposition occurs, slowly wetter conditions are created that allow the area of wetland to expand.
Peat is found in wetlands and bogs across many countries and is usually accumulates slowly at the rate of about a millimeter per year.
It is the first step in the formation of coal and slowly becomes lignite after pressure and temperature increase as sediment is piled on top of the partially decaying organic matter.
In order to be turned into coal, the peat must be buried from 4-10 km deep by sediment.
Since peat becomes coal over time, it is classified as a fossil product.
Peat stores a very high amount of carbon and is considered as carbon sink.
Although peat is not used widely to generate electricity as it has a low carbon content, less than 60%, it is still used for domestic heating in some places around the world.
Page No 9:
Question 5:
Biological classification is a dynamic and ever evolving phenomenon which keeps changing with our understanding of life forms. Justify the statement taking any two examples.
Answer:
Classification has been a centre piece of biology ever since Linnaeus, who gave two kingdom classification, Plantae and Animalia . These groups are made on the basis of structural and cellular difference like plant possess cell wall, central vacuole, whereas animals lack cell wall and central vacuole but the drawback in this system of classification was that eukaryotic and prokaryotic organisms like Euglena, Bacteria and fungi were not included in this kingdom classification.
This was replaced by three kingdom classification suggested by Haeckel, where unicellular eukaryotes were kept under Kingdom-Protista and finally in 1969, Whittaker proposed five kingdom classification. Even the most accepted, the five kingdom classification was modified by Carl Woese, who based upon his understanding of bacteria divided the Monera into archaebacteria and eubacteria. This change happened because the criteria for classification changed.
This kind of changes will take place in future too depending on the improvement in our understanding of characteristics and evolutionary relationships. So, biological classification is a dynamic and ever evolving phenomenon which keeps changing with our understanding of life forms.
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