Life Science(Biology)

Taxonomy Unit:l (1) Define Taxonomy . According to Mayr(1982)  " Taxonomy is the theory and practice of classifying organisms ". (2) Define Systematics . According to Simpson (1961) " Systematics is the scientific study of the kinds and diversity of organisms and of any and all relationships among them". (3) Define Zoological classification . The ordering of animals into groups /sets on the basis of their relationships or of associations by contiguity , similarity or both is called Zoological classification . (4) Define Phenon . Different forms or phenotypes  like sexual dimorphism , age stages ,seasonal varities and morphs or individual varients , etc. of a single population are termed as Phenon . (5) Define Taxon. According to Simpson 1961 " Taxon is a group of real organisms recognised as a formal unit at any level of a hierarchic classification . (6) Define Category . The term used to designate rank or level in a hierarchic classification is a Category. (Sp...

Causal Organism: Macrophomina phasiolina of   Deuteromycetes   , a facultative parasite since, it can live as a parasite in jute plant and also as a saprophyte in dead organic material.    Rhizoctonia bataticola is it's sclerotic stage. Symptoms Symptoms of rot are visible on seedling , on mature plants ,in roots & in fruits . (1) On seedlings  : (i) Necrotic symptoms as rot or death & disintegration of tissue appear on the root, hypocotyle,cotyledon & in the apex of new born seedling. (Ii) When inoculum is from soil, blackish brown thin streaks appear on collar of epicotyle & toppling down of the seedling(1 to 20 days old) i.e.damping off appears and seedling dies at humid condition.  If the seedling is of 21days and onwards , streaks appear on collar but does not shows damping off . (iii)  When weather is dry & seedling is at "three leaves stage" ,then blight appear  & also necrotic lessions on leaves, as...

(1) Name two amonifying bacteria . Bacillus mycoides , B . ramosis ,B. vulgaris (2)Name two Nitrifying bacteria. Nitrosomonas, Nitrococcus,Nitrosospira. (3) Name two Nitrogen fixing bacteria . Rhizobium leguminosorum... a symbiont. Clostridium sp    a free living bacteria. (4) Name two bateria involved in retting of jute. Clostridium botulinum ,C. perfringens . (5)Name two bacteria  which are used to check petroleum pollution. Pseudomonas , Acromonobacter , Candida & Micrococcus. (6)Name two antibiotic along with source . (i) Bacitracin......... Bacillus subtilis ....... ... prevents  gm + bacterial cell wall formation . (ii) Colistin.... B. colstins ..... inhibits cell wall formation of gm(-) bacteria & cocci. (7) What is Acid-fast bacteria ? The bacteria which retains the initial stain and it is difficult to decolourise with acid  alcohol e.g. Mycobacterium tuberculosis & M. leprae. (8) How do acid fast bacteria be stained ? By Ziehl -Neilson techn...

How a virus differs from a bacterium ? A virus differs from a bacterium in the following features: (1) There is no cellular organisation like cell wall and cell membrane in viruses but a bacterium have . (2) Viruses are submicroscopic & smaller than bacteria . (3)A virus never be free living , it is always  obligate parasite , but a bacterium may be free living . (4) A virus can not keep DNA and RNA at the same time , but a bacteria can . (5) A virus does not have  own metabolic enzymes , protein synthetic mechinery but a bacteria has all these . (6) A virus can not perform binary fission but it is a common phenomenon for a bacteria . Bacteriophages :  Viruses parasitic on bacteria are termed as Bacteriophages. They may contain ssDNA, dsDNA,ssRNA or dsRNA. Types of bacteriophages on the basis of morphology  Morphologically bacteriophages are of six types: (1) A phage with a head , rigid tail having contractile sheath and fibres . (2) A phage with a head ,flexible...

Several members of Deuteromycetes, a few Ascomycetes & Basidiomycetes perform plasmogamy,karyogamy & meiosis (haplodisation) in their life cycle but not at a specific time and specified points . This abnormal behaviour of such fungi is termed as parasexuality . Pontecarvo & Roper , 1952 first discovered parasexuality  in Aspergillus nidulans and also coined this term (Greek , para=beside of sex ).A few fungi which perform parasexuality are : Aspergillus nidulans, A.niger, A fumigatus ,A. oryzae, Penicillium chrysogenum , P.expansum, P.italicum,Fusarium oxysporum,Ustilago maydis,etc. Mechanism: Pontecarvo,1956 observed the following steps of parasexuality in Aspergillus  nidulans: (i) Formation of heterokaryotic   mycelium :  Anastomosis of somatic hyphae of different genetic constitution , fusion of some nuclei and their subsequent division and mutation of one or more nuclei of a homokaryotic mycelia in some Ascomycetes resulted into heterokar...

1.Carbon monoxide is a pollutant because (A) it reacts with O² (B) it inhibits glycolysis (C) it makes nervous system inactive (D) it reacts with hemoglobin 2. Taj Mahal is said to be suffering from"Marble Cancer"means (A) acid rain which corrode marble (B) large number of fungus in Taj Mahal marbles (C) yellowing of the marble on account of soot particles (D) smokes filming the Taj Mahal from adjoining industries 3. Which gas is responsible for depletion of Ozone layer (A) Chloroflurocarbon (B) Nirogen (C) Oxygen (D) Nitrogen oxide 4. India celebrates Van Mahotsav every year in the month of ______ when lakhs of tree are planted across the country (A) June (B) July (C) August (D) September 5.As per World Wide Fund for nature, which river is the most endangered in the world? (A) Ganga (B) Jumuna (C) Brahmaputra (D) Mahanadi 6. Which of the following groups of plants can be used as indicators of pollution? (A) Epiphytic lichens (B) Ferns (C) Liverworts  (D) Hornworts 7.Which of...

1. Answer in brief: ................1 mark each (a) Name two de-nitrifying bacteria . (b) What is meant by eucarpic thallus? (c) What is episome? (d) Distinguish between primary and secondary mycelium. (e) What is non-systemic fungicide ? 2. Mention the living and non- living characters of virus . Describe the structure of TMV with suitable diagram . Discuss the basic features of lytic and lysoenic cycles . 4+(5+2)+4=15   3. Why are bacteria called prokaryotes ? Describe generalised transduction . How does it differ from specialised transduction? Compare the conjugation between F+ x F-  and  Hfr x F-. 2+(5+2)+6 4. What are ascocarps ? Mention the different types of ascocarps .Briefly describe the structure and development of ascocarps of Penicillium and Ascobolus. Out of these two , which one should be considered as more advanced and why ? 1+1¹/2+(2+8)+1+1¹/2 5. Why are the species of Polyporus called as bracket fungi ? Name the process through which Polyporus  perfo...

1 . Vivipary is  (A) seed germination with subterranean cotyledons (B)seed germination with epiterranean cotyledons. (C) fruit development without pollination. (D) seed germination inside the fruit, the fruit while attached to the plant. 2.Seed dormancy allows the plant to  (A) overcome unfavourable climatic conditions. (B) develop healthy seeds. (C) reduce viability (D) prevent deterioration of seeds . 3. Seed dormancy may be due to (A) immature embryo. (B) hard seed coat . (C) presence of germination inhibitors (D) All of the above. 4. Protein % of paddy straw mushroom is  (A) 4.98% (B) 3.98% (C) 5.98% (D) 2.98% 5.SCP means  (A) Special Collective Protein (B) Single Cell Protein (C) Single Cell Phospholipid (D) Special Cell Protein 6. Seed viability can be determined by  (A) Iodine test (B) ELISA test (C) Tetrazolium test (D) Ames test   7.Exposing seed to chilling temperature for germination is known as  (A) scarification (B) stratification (C) laye...

Systematic Position     Kingdom            Mycota Division.                 Eumycota Sub-division.          Basidiomycotina Class.                      Hymenomycetes Sub-class.               Holobasidiomycetodae Order.                      Aphyllophorales Family.                     Polyporaceae Genus.                      Polyporus Common name : Bracket Fungi , because the outer margin of the basidiocarp looks like first brackets or Pore fungi , because on the under-surface  of the fruit body / basidiocarp many fine pores are present. Indian species : India represents 159 species of Polyporus like P. ...

1. Ans in brief.  1 mark each a. What is clump formation? b.What is brachymeiosis? c. What is viroid? d.What is flagellin? e. Give the composition of Bordeaux mixture. f.Name the biological source of orcein. g. What is mycotoxicosis ? h.Which type of bacteria are called pleomorphic type ?  i.What is bacteriophae ? 2. Give an account of the cell wall structures and composition of gm+ & gm- bacteria.Add a note on their appendages .8+4 3. What do you mean by acid-fast bacteria? 2 4. What is meant by dikaryotization ?2 5. Add a note on spore dispersal in Agaricus spp.5 6. Why is Deuteromycetes called as imperfect fungi ? Mention different types of spores of Deuteromycetes . Write economic importance of this group.1+4+3 7. Mention the different ways through which the plant pahogen gets entry within the host tissue.2 8. Describe in brief the host-parasite relationship which leads to the disease establishment .7 9. What is hypersensitivity ?2 10.Write a brief note on biological c...

1. Answer in brief        1 mark each (a) What is nucleoid? (b) Why is Puccinia graminis tritici called polymorphic fungus ? (c) Distinguish between virion and viriod . (d)What is mesosome? (e) What is dropsy ? (f) Name the lichen from which antibiotic is obtained. (g) What is pseudomycelium? (h) What is eucarpic thallus ? Give example . (i) What do you mean by non-replicative form of virus ? (j) What is lambda dg? (k) Name the phytoalexin found in Pisum sativum. (2) What is bacterial capsule ? Give a comparative account of cell walls of gm + & gm- bacteria .Write a brief note on bacterial endospore .What do you mean by acid-fast bacteria ? 2+6+5+2 (3) What is episome ? Describe , in brief , the different stages of T⁴ phage multiplication process . Enumerate the different groups of plant viruses as suggested by ICN of viruses .2+8+5 (4) What do you mean by bipolar and tetrapolar species in Basidiomycetes?Give an account of structural organisation of a typical bas...