Life Science(Biology)

1. Answer in brief :.                  1 mark each (a) What do you understand by map unit ? (b)Define pseudoalleles. (c)What is incomplete linkage ? (d) What are Okazaki framents? (e) Define frameshift mutation . (f)What is synthetic cross ? (g)What is meant by somatic embryo ? (h)Differentiate between continuous and discontinuous variable . (i) What is restorer gene ? (2) What is equational division ? Why is meiotic division -l called reductional division ? If reduction occurs in 1st division of meiosis, why is there necessity for 2nd division to complete process of meiosis? Why is meiotic division-l not considered as true reduction division when crossing over occurs at prophase -l ? What is MPF ? Illustrate the role of p 34 protein kinase in progression of mitotic cell cycle. 2+2+2+2+2+5=15 (3) Define polysome . Mention the types of RNA and their occurrences that are found  in 80S & 70 S ribosomes . Describe the 'Fluid Mosaic ' model of the plasma membrane .2+(3+3)+7=15 (

(1) How does bacterial conjugation differ from transformation process ? Elucidate the significant features of F factor. Distinguish between F+ cells and Hfr cells.Describe with suitable diagram the bacterial conjugation process .2+3+3+7=15,TU2011H (2)What are Eubacteria? With suitable figures, describe the structure and function of (i) nucleoid (ii)bacterial flagella & (iii)plasmid.Write a note on the role of bacteria in controlling soil fertility. 1+(3+5+3)+3=15,TU2011 H (3)What is Penicillus? With labelled sketches, describe the structure of Penicillus. Write the process of cleistothecium formation in Penicillium.Name the species of Penicillium from which penicillin is produced commercially. What is heterothallism?1+4+7+1+2=15 (4) What is plasmogamy?Citing examples, describe the different processes of plasmogamy that are found in sexual reproduction in fungi.With labelled figures, describe the internal structres of the sporophore of Polyporous .1+8+6=15 (5) What are lesional &

Layering  is a technique to induce adventitious roots on a stem while the stem is already attached to the mother plant . Types of Layering: Layering are of eight types: (i)  Simple (ii) Compound (iii)Serpentine (iv)Air (v)Mound/Stooling (vi)Trench (vii) Drop and (viii)Tip Layering The techniques of each type is discussed below : Simple Layering: ( a) Time :Early Spring  ,Stem to be used : One year old which is easy to bent . (b) One yr old stems are bent to make "U" -like structure 15 -20 cm away from the tip. (c) The base of the "U" is pegged down and covered by soil to induce rooting . (d) In the next Spring the stem is cut off behind the rooting portion. Compound Layering: (a) At first mother plants are planted 1.8 to 3 mt apart in the permanent nursery beds . (b) The entire shoot is laid down horizontally on the soil , pegged down  and covered by rooting media . (c)Within a year new roots will appear from each node along with new shoots. (d) After re

Basidiomycetes 1.The mycelium is branched,septate with simple pore (Uredinales & Ustilaginales ) & dolipore (Agaricales) 2. The mycelia are of 3 types: Primary: Monokaryotic, ephemeral & formed from basidiospores . Secondary:  Dikaryotic & formed by the dikaryotization of primary mycelium . Tertiary: Dikaryotic ,formed from the secondary mycelium & termed as basidiocarp ( Agaricus , Polyporus, etc.) 3 .There is no specialized sex organs  and sexual reproduction is just the fusion of two nuclei of different strains (+& -). 4. Meiosis takes place immediately after karyogamy in basidium to form 4 haploid nucleus which are lastly converted to exogenous basidiospores. 5. Clamp connection is a common phenomenon. 6. Basidia are of 2 types: Holobasidium is non-septate having 4 terminal sterigmata bearing a spore at the tip . Phragmobasidium is septate bearing a lateral sterigmata with a spore . Difference between Basidiomycetes and Ascomycetes (1) Septation:  In Basidio

1.What is virion ? 2. What is disease triangle ? 3. What is heterocious rust ? 4.What is spore print ? 5.What is mitosporic fungi ? 6.What are primary and secondary homothallic fungi? 7. How do atrophic symptom differ from hypertropic symptoms ? 1.Enumerate different types of virus according to their genome . 5 2. What do you mean by cyanophage and bacteriophage ? 2 3. Describe the structure of T⁴ phage with suitable diagram.6+2 4. Describe the cell wall structures of gm (+) & gm(--) bacteria .3+3 5. Illustrate the transformation process with special emphasis of DNA uptake .5+2 6. Comment on extranuclear DNA found in bacteria. 2Wt 7.Name two edible & two poisonous species of Agaricus .2+2 8. Describe the basidiocarp of Agaricus with diagram .5+3 9.State the nutritional components of Agaricus ,3 10.Write down the symptom of black stem rust of wheat in primary host .5 Describe the disease cycle with annual recurrence in India .5+2 Mention their most effective control measures of

Ascomycetes (1) The mycellium is branched, septate with simple pore . (2) Pimary mycellium is uni - or multinucleate ,but ascogenous hyphae are always binucleate . (3) Terminal conidia of conidiophore are common asexual spores of many species . (4) Karyogamy is performed in the young ascus & immediately followed by meiosis and mitosis  respectively to produce endogenous 8 ascospores . (5) There is no any motile structure in the lifecycle. (6) Asci are protected by ascocarp of three types : (i) cup -shaed apothecium e.g. Ascobolus. (ii)flask-shaped perithecium e.g. Daldenia . (iii)  closed & round cleistothecium e.g. Penicillium . (7) Hook or Crozier formation is common during ascus  formation. (8) Sexal reproduction is variable : (i) gametangial copulation e.g.Yeast (ii) gametangial contact e.g. Penicillium ( iii) somatogamy e.g. Morchella (iv) spermatisation e.g. Polystigma .

Phycomycetes (1) Either mycelium absent /rudimentary (e.g. Synchytrium ,Olpidium ) or well-developed (e.g. Pythium, Mucor, etc ). (2) Mycelium is non-septate & coenocytic . (3) Asexual reproductive units are endogenously formed sporangiospores (zoospores e.g.  Synchytrium  or aplanospores ) (4) In Oomycetes sexual reproduction is oogamous ,e.g. Pythium,Phytophthora,etc & isogamous in Zygomycetes . (5) Zoospores are flagellated and motile . (6) Dikaryophase is absent due to the fact that karyogamy follows plasmogamy immediately . (7) Zygote produced sexually is simple and unicellular .

  (1)  A large number of Ascobolus species are monoecious but self-sterile , hence antheridial and ascogonial branch of two strains (A strain and B strain ) grow  together.   (2)  Antheridium is multinucleated , club shaped and stalked ; similarly ascogonium is globose but initially uninucleated  and having a receptive trichogyne.  (3) The trichogyne coils around the male antheridium and point of contact dissolves. Fertilization:  (1) The male nuclei migrate into  female ascogonium and the female nucleus starts mitosis . (2) The opposite nuclei fuse in pairs to make 2n  nuclei . (3) The 2n nuclei performs repeted mitosis to make several 2n nuclei . (4) Then numerous ascogenous hyphae arise from the ascogonium which elongate and septate having a pair of 2n nuclei in each compartment. (5) The tip of the ascogenous hyphae develope crozier and penultimate cell of the crozier turns into  ascus with two 2n nuclei at early stage . (6) In the ascus two nuclei fuse to form 4n zygote nucleus .

Degeneration  of sex in fungi :-         In Fungi, simplification of sex organs is observed from lower groups to upper groups:-       1.In Mastigomycotina,a lower group of fungi,isogamy,anisogamy or oogamy resulted into zygote.         2.In Ascomycotina & Basidiomycotina, the sexual reproduction process is progressively simplified in different directions with well- established sexuality.         3 Whereas ,sex organs are absent in few higher fungi of basidiomycotina,though sexual reproduction is well established. Degenaration sex in non - septate and ceonocytic fungi :-           1. The members of Oomycetes of Mastigomycotina , like Pythium , Phytophthora etc.female oogonium is fused by male antheridium to develop either oospore or zygote. It is considered as an advanced type of sexual reproduction.         2. In the members of Zygomycotina like Mucor,Rhizopus etc, morphologically similar but physiologically disimilar (+ and -) gametangia copulate to from zygospore . It means that

 Dangeard in 1907 observed the sexual reproduction in P. vermiculatum ,  which is as follows: ·    A long, straight and club-shaped ascogonium(female) developed from mycelium. ·    It’s nucleus divides mitotically into 64 nuclei. ·    Simultaneously, a uninucleate male antheridial branch arises and coils around the female body. ·    Then a septa forms to make terminal antheridia which swells , turns club- shaped and uninucleate. ·    The antheridial tip touches the wall of the ascogonium & the point of contact dissolve but antheridial nucleus does not pass into the ascogonium i.e. remains non- functional . ·    Meanwhile , ascogonial nuclei get paired (termed autogamy)  & after that segmented leaving dikaryon in each chamber . (In P. glaucm instead of autogamy it performs plasmogamy i.e. the content of antheridium i.e. 32 -64 nuclei formed by repeted mitosis in trichogyne  migrate in the female ascogonium ). ·    From each bi-nucleate chamber new ascogenous in

Camelus dromedarius adapts itself when there is prolonged water scarcity , high temperature and non-availability of feed resources or feed quality is poor .   Many physiological adaptations are observed in a camel to : 1. Conserve water 2. Dehydrate the blood 3. Prevent cellular damage at high temperature. 4. Regulate body temperature. The above features are discussed below :- Conse rvation of water   (1)Water turnover rate in camel is 38-76 ml/kg.It increases body temp.and also stores CO2 and glucose in the blood to reduce urine production to concentrate urine and to reduce sweating at hot arid conditions. (2) It can survive 6-14 days without water and can tolerate 30% water loss. (3)It drinks 1/3 rd of its body weight to rehydrate it  and stores in gut for 24 hrs to avoid rapid dilution of blood. (4)The ratio of medulla/ cortica is 4/1 which allows high reabsorption of water in kidney thus makes the urine concentrate (3200 mOsm). (5)      It follows bi-phasic

  Penicillium reproduces asexually by means of conidia . A conidiophore is an erect , tubular hypha which arises from any cell of the mycelium. Conidiophore may be unbranched or branched . Unbranched conidiophore : (1)   In case of P. spinulosum and P. thomii phialides are borne directly on the tip of each conidiophore . (2)      On each phialide chains of conidia are borne exogenously . (3)      In P. claviforme many conidiophores aggregated to form club-shaped structure coremium and conidia developed directly on them .  B ranched conidiophore :  A large number of species like Penicillium digitatum ,P. expansum , P. vermiculatum etc primary ,secondary and tertiary branches are formed . (i)      Primary branch …     Ramus (ii)     Secondary branch… Metula (iii)   Tertiary branch……. Sterigma or Phialide.        (a)  Primary branches are formed at the tip of conidiophore.        (b) Secondary branches are formed at the end of each ramus.        (c) Te