Chapter no 2) Systematics of Living Organisms

 1. Choose correct option:

A. Which of the following shows single

stranded RNA and lacks protein coat?

c).Viroid 

a. Bacteriophage b. Plant virus

c. Viroid d. Animal virus

B. Causative agent of red tide is a)dinoflagellate

a. Dinoflagellate b. Euglenoid

c. Chrysophyte d. Lichen

C. Select odd one out for Heterotrophic

bacteria. c)Methanogens 

a. Nitrogen fixing bacteria

b. Lactobacilli

c. Methanogens

d. Cyanobacteria

D. Paramoecium : Ciliated Protist

Plasmodium : d)Sporozoan 

a. Amoeboid protozoan b. Ciliophora

c. Flagellate protozoan d. Sporozoan

2. Answer the following:

A. What are the salient features of monera?

Ans)

i)Size: The organisms included in this kingdom are microscopic, unicellular and prokaryotic (cells lack a well defined nucleus).

ii. Occurrence: These are omnipresent, means, they are found in all types of environments, including those which are not generally inhabited by other living beings.

iii.Nucleus: These organisms do not have well

defined nucleus. DNA exists as a simple double stranded circular, single ring, without nuclear membrane called as nucleoid. Apart from the nucleoid they often show presence of extrachromosomal DNA which is small circular called plasmids.

iv. Cell wall: Cell wall is made up of peptidoglycan (also called murein) which is a polymer of sugars and amino acids.

V. No Membrane bound cell organelles: Membrane bound cell organelles like mitochondria, chloroplast, and endoplasmic reticulum are absent. Ribosomes are present, which are smaller in size (70S) than invi. Nutrition: Majority are heterotrophic, parasitic or saprophytic in nutrition. Few are autotrophic that can be either photoautotrophs chemoautotrophs. or

vii. Reproduction: The mode of reproduction is

asexual or with the help of binary fission or budding. Very rarely, sexual reproduction occurs by conjugation method (using sex pili).

viii. Examples: Archaebacteria: e.g. Methanobacillus, Thiobacillus, etc.

Eubacteria: e.g. Chlorobium, Chromatium, and Cyanobacteria e.g. Nostoc, Azotobacter, etc.

B. What will be the shape of bacillus and

coccus type of bacteria?

Ans)

the shape of bacillus type of bacteria is rod-shaped and coccus is spherical.

C. Why is binomial nomenclature important? 

Ans)

Binomial nomenclature is important because;

i)The binomials are simple, meaningful and precise.

ii)They are standard since they do not change from place to place.

iii)These names avoid confusion and uncertainty created by local or vernacular names.

iv)The binomials are easy to understand and remember.

v)It indicates phylogeny (evolutionary history) of organisms.

vi)It helps to understand inter-relationship between organisms.

3. Write short notes:

A. Useful and harmful bacteria.

Ans)

i. Useful bacteria: Most of the bacteria act as a decomposer. They breakdown large molecules

into simple molecules or minerals.

Examples of some useful bacteria:

•Lactobacillus:It helps in curdling of milk.

•Azotobacter: It helps to fix nitrogen for plants.

•Streptomyces: It is used in antibiotic production such as streptomycin.

•Methanogens: These are used for production of methane (biogas) gas from dung.

•Pseudomonas spp. and Alcanovorax borkumensis: These bacteria have the ability to destroy the pyridines and other chemicals.Hence, used to clear the oil spills.

ii. Harmful bacteria: This includes disease

causing bacteria. They cause various diseases like typhoid, cholera, tuberculosis, tetanus, etc.

Examples of some harmful bacteria:

•Salmonella typhi: It is a causative organism of typhoid.

•Vibrio cholerae: It causes cholera.

•Mycobacterium tuberculosis: It causes tuberculosis.

•Clostridium tetani: It causes tetanus.

•Clostridium spp.: It produces a toxin that causes food poisoning.

•Many forms of mycoplasma are pathogenic.

•Agrobacterium, Erwinia, etc are the pathogenic bacteria causing plant diseases.

•Animals and pets also suffer from bacterial infections caused by Brucella, Pastrurella, etc.

B. Five Kingdom system

Ans)

Five kingdom system of classification was proposed by R.H. Whittaker in 1969. This system shows the phylogenetic relationship between the organisms.

The five kingdoms are:

i.Kingdom Monera

ii. Kingdom Protista

iii. Kingdom Plantae

iv. Kingdom Fungi

V. Kingdom Animalia

C. Useful Fungi

Ans)

Economic importances of fungi are as follows:

i. Role of fungi in medicine:

a. Antibiotic Penicillium is obtained from

penicillin 

b.Drugs like cyclosporine, immunosuppressant drugs, precursors of steroid hormones, etc are isolated from fungi.

ii.Role of fungi in industries:

a.Yeast is used in bread making. It causes dough to rise and make the bread light and spongy. It is also used in breweries or wine making industries. Sugars present in grapes are fermented by using yeast. This results in production of alcohol which is used for making wine.

b.Lichen is a symbiotic association of algae and fungi are used in preparation of litmus paper which is used as acid-base indicator.

iii)Role of fungi in food:

a.Fungi like mushrooms are consumed as a food. These are rich source of protein.

b.Fungi genus Penicillium helps in ripening of cheese.

iv.Role of fungi as biocontrol agents:

a.Fungi help to control growth of weeds.

b.Pathogenic fungi like Fusarium sp., Phytophthora palmivora, Alternaria crassa, etc act as mycoherbicides.

4. Complete tree diagram in detail

Ans).

5. Draw neat labelled diagrams:

A. Paramoecium

Ans)

B. Euglena

Ans)

C. TMV

Ans)

6. Complete chart and explain in your word:

Ans)

Depending upon the host, viruses are classified into three types as:

i. Plant virus 

ii. Animal virus

iii. Bacteria (Bacteriophage)

i. Plant virus:

a. Generally, they are rod shaped or cylindrical with helical symmetry.

b. Majority of plant viruses have RNA as their genetic material. (Exception: Cauliflower Mosaic Virus has double stranded DNA as genetic material)

C. Plant viruses cause disease in plants. e.g. Tobacco Mosaic Virus (TMV).

ii. Animal virus:

a. Generally, they are polyhedral in shape with radial symmetry.

b. They have either DNA or RNA as genetic material.

C. It causes disease to majority of animals including human beings. e.g. Influenza virus.

iii. Bacteria (Bacteriophage):

a. They have tadpole-like shape.

b. They have tadpole-like shape with binal symmetry.

c. Bacteriophages were discovered by Twort.

d. Bacteriophages have double stranded DNA as the genetic material.

e. Its body consists of head, collar and tail

7. Identify the following diagrams, label

 them and write detail information in

 your words

A)

Ans)

The given figure represents Euglena

Characteristics:

i.It belongs to Kingdom Protista.It is further classified into euglenoids.

ii. They lack cell wall but have a tough covering of proteinaceous pellicle.

iii. Pellicle covering provides flexibility and contractibility to Euglena.

iv. They possess two flagella, one short and other long.

v. They behave as heterotrophs in absence of light but possess pigments, similar to that of higher plants, for photosynthesis.

B)

Ans)

The given figure represents Mucor.

Characteristics:

i. It belongs to class phycomycetes of kingdom fungi.

ii. Mycelium is made up of aseptate coenocytic hyphae.

iii.It commonly grows on decaying fruits, vegetables, in soil, on various food- stuff-like bread, jellies, jams, etc.

iv. In favourable conditions mucor reproduces asexually by formation of spores within sporangia. It can also reproduce by sexual means.

C)

Ans)

The given figure represents Paramoecium 

Characteristiscs:

i. It belongs to kingdom Protista. It is further classified as Animal-like protist.

ii. It lacks cell wall.

iii. It shows heterotrophic and holozoic nutrition.

iv. It is a ciliated protozoan where locomotion is due to cilia.

v. It has gullet (a cavity) which opens on the cell surface.

D)

Ans)

The given figure represents Bacteriophage.

Characteristics:

i.They have tadpole-like shape.

ii.They have tadpole-like shape with binal symmetry.

iii.Bacteriophages were discovered by Twort.

iv.Bacteriophages have double stranded DNA as the genetic material.

v)Its body consists of head, collar and tail.

E)

Ans)

The given figure represents Aspergillus.

Characteristics:

i. It belongs to class ascomycetes of kingdom Fungi.

ii.It is multicellular.

iii.The hyphae are branched and septate.

iv. Aspergillus grows well in soil, decaying vegetation, hay, dung, on plants, etc.

V. Asexual reproduction takes place by spores called conidia which are produced at the tip of hyphae called conidiophores.

F)

Ans)

The given figure represents Agaricus (Mushroom).

Characteristics:

i.It belongs to class basidiomycetes of kingdom Fungi.

ii.It has branched septate hyphae.

iii.It grows in soil, on rotten wood, etc.

iv.It is edible and rich in proteins.

V.Vegetative reproduction takes place by fragmentation.

8. The scientific name of sunflower is given

 below. Identify the correctly written

 name.

 A. Helianthus annuus L.

 B. Helianthus Annuus l.

Ans)Helianthus annuus L.

9. Match the following:

Ans).

i.Monera- b.Cyanobacteria

ii.Protista- d.diatoms 

iii.Plantae- a.Riccia

iv.Fungi- c.Rhizopus 

10. Complete the following:

 A. Plant-like Protista - Diatoms

 B.Animal like Protista - Entamoeba