Life Science(Biology)

          GONDWANA FLORA OF INDIA                                                                                                         (1) Who suggested the name Gondwana ?    1 (2) What is "Gondwana System" ?  Add a note on the distribution of Indian Gondwana rocks.3/TU 2011 H (3) Classify Indian Gondwanas on the basis of the period of dominance of principal genus .  3 (4) Name the major flora of the following :.               (i) Lower Gondwana    8/TU 2012H      (ii) Middle Gondwana  6/TU 2011 H      (iii) Upper Gondwana of India (5) Name few Mesozoic Gondwana flora  ....

(1) What is telome theory ?................2 (2)Discuss with suitable illustrations and examples the possible origin of sporophyll with axillary sporangia and sporangiophore from telomes in Pteridophytes ..........(8,H.TU;2007) (3) State merits and demerits of Telome Theory.............5 (4) Discuss the origin of sporophylls in Lycopsids , Sphenopsids and Ferns as has been visualised by Zimmerman .......3×3 ,TU,2012,H. (5) Mention the facts which suppport Algal origin of Pteridophytes .......2 (6) Critically explain the Anthocerotean theory of the origin of Pteridophytes.........8,TU,2011,H. (7) What is Seed habit ? Explain how seed habit evolved from heterospory .      2+5 ,TU,2011,H. (8) Characterize different types of steles found in Pteridophytes with suitable illustrations . Add a brief note on the evolution of said stelar types.   6+6,TU,2006,H. (9) Differrntiate the stele of Lycopodium from that of Sellaginella .      ...

Life Cycle in Angiosperms In Angiosperms the diploid (2n) Sporophytes alternate with haploid (n) Gametophytes, hence , the life-cycle is called as Diplo-Haplontic . Sporophytic Phase (2n) : (A) The plant body with definite roots , stems ,leaves and flowers with vascular bundles is a Sporophyte . (B) It bears two types of sporophylls viz. ; the stamens (microsporophylls) and pistils (megasporophylls) in flowers . (C) Each microsporophyll have four microsporangia in the form of pollen chambers having diploid  microspore mother cells (MMC). Similarly , each megasporophyll encloses one to many ovules with diploid megaspore mother cells (MMC) in the megasporangium . Sporophyte (2n) to Gametophyte (n) : On the onset of meiosis in MMC (2n) and with the formation of haploid spores the gametophytic phase (n) starts where the development of female gametophyte is monosporic. Gametophytic Phase (n) : (D) The microspore or the pollen grain (n) and the functional megaspore (n...

Principle : In general, when seeds are immersed into water, the water is soaked up and the seeds swell up considerably,and the phenomenon is termed as imbibition. Since imbibition is a biological process temperature has an influence.So, van't Hoff's law will play a positive role on imbibition. The law states that, with a rise of every 10°C there is a doubling of the speed of the reaction .       Q10 is the measurement of the rate of change of a biological or chemical system as a consequence of increasing the temperature by 10°C. Hence, Q10 is a ratio of the two values of a biological system at two temperature differ by 10°C.                      (T2--T2)/10°C.                    Q10.                       =  R2/ R1, where R= the rate; T= temperature at Celsius ° or Kelvin ; Q10is unit...

                                                                                                  In each year a good number of tender bamboo shoots were sold in the markets  of Tripura in the trade name "usei" or "baskarul" . Not only in India , but also it  has an world-wide use as it is having a good food value . 100 gm of fresh shoot provide 27 kcal energy, 5.2 gm carbohydrates, 2.6 gm  protein, 0.3 gm total fat, 2.2 gm ditery fibre,4 mg Na, 533 mg K, 13 mg Ca ,0.190 mg Cu ,0.50 mg Fe,3 mg Mg,0.262 mg Mn, 59 mg P, 1.10 mg Zn. According to Visuphaka ,1985; Xia,1989 ; Shi and Yang 1992 it is rich rich in vitamins like  Niacin , Thiamine , vit A , vit B6 , vit E ,etc.17 amino acids are obtained ,out of which 8 are essentia...

More than 100 species of Pheophyceae,Rhodophyceae,Cholorophyceae and Cyanobacteria are the good sources of protein,carbohydrates ,polyunsaturated fatty acids,lipids, minerals,vitamins and fiber content;hence used as human food . According to FAO (2014), 38% of the global production of sea weeds(23.8million,2012) is consumed as kelps, nori and laver.             Among Pheophyceae,   the genera like A laria,Laminaria, Sargassum,Durvillea and Pe lvetia  are used as food in different parts of the world:- i) kombu- It is a famous dish of Japan which is prepared from La minaria (57% carbohydrates). ii) Sarumen- It is prepared from A laria in Japan. iii)Cachiyago- Dried and salted   Durvillea prepared by natives of South America. The food value of brown algae is:-        Protein-  6.15%  (17 amino acids)        Fats      -  1.56%       ...

        Primitive characters of Magnoliaceae                 Hutchinson ,1959has treated Magnoliaceae as the most primitive family among the Angiosperm in his famous book"Families of Flowering Plants"due to the following characters :                                           (1) Spiral arrangement of stamens and apocarpous pistils on the elongated and conical axis.                                                        (2) Presence of tracheids with bordered. pits in the wood of the genus Drimys is  Gymnosperm character.                                    (3) T...

 Just now Tutu rang me that the Queen of RKM is no more ! She was the centre of attraction of English Department. She had a strong grasp on the English Romantic Poetry.I will compare her with the Champa of Magnoliaceae because Magnoliaceae is the primitive among Dicot similarly Ramkrishna Mahavidyalaya is one of the premiere academy in Tripura ,the second oldest college of the state .At the same time Michelia champaca is famous for fragrance and pale-yellow colour. Pinki was also famous for her fragrance of English Literarure,specially for British Poetry of Victorian era.  She herself was pale-yellow in colour.                                                                        I meet her first in 1983 when she was a kid and there is a family relationship with her.My son Roni was her ...

       Polysiphonia is a Red Marine Alga and a good number of siphon-like cells constitute the thallus structure of it . A series of events take place after the  formation of the zygote  which are as follows:.                                   (1) At first an auxillary cell is formed from the supporting cell and placed in between the carpogonium and  the supporting cell.                                                          (2) Then a tube is formed to connect the carpogonium and the auxillary cell.                      (3) Next the 2n zygote nucleus divides mitotically to form it's replica and one of them is migrated to the auxillary cell from the carpog...

        Can you believe that you may count the age of a tree.Even you may tell about the past climatic conditions just by studying a timber or a tree trunk ! Yes, you can do it. This is a branch of Science and termed as Dendrochronology.                                                                  Andrew E. Douglass founded the technique of dating events by studying the pattern of growth rings in tree trunks in the late 1800s and early 1900s and established the Laboratory of Tree-Ring Research at the University of Arizona.                                                 In most of the temperate trees and shrubs annual-rings are formed due to the secondary growth.A ...

                                                                          Ralf Warldo Emerson said "Earth laughs in flowers". So if you want to be healthy, Wealthy and wise then, make an interest in gardening and be a member of that garden. Marigold is one of the common and most popular flowers in India  and its generic epithet is Tegates . The common species are T.erecta (African marigold), T.petula (French marigold) and T.tenuifulia (Signet marigold), etc.                        The African marigold has different varities like"Giant double " , 'African Orange', "Crack Jack","Guinea Gold ","Climax","Tordeaur",and "Yellow Supreme". It's color range from orange .lemon yellow and golden yellow. The size of the flowers range from 5...

       Amarbel or Swarnalata i.e., Cuscuta reflexa of Convolvuliaceae is  a slender leafless,nongreen yellow twining vine parasite on other Angiosperms.Students of the primary classes are very familiar with this plant as it's name is uttered during the study of nutrition chapter.It propagates by seed which germinates to a Seedling. This young one shows peculiarity during the search of the host.                                                      At very early stage it becomes very long filament possessing few green pigments but looses the root.It's cotyledons are under developed and it lenghen the filament tip by the expence of the reserve food.When the host is available, immediately the filament coils round the host and pushes it's hostoria to suck the food.The search process continue for days, but if the search of...

  On Monday, the 10th February,2020 the AAP Supremo Arvind Kejriwal set a new precedent by urging their party supporters and volunteers not to burst firecrackers during victory celebrations to prevent air pollution. It is just a matter of awareness about the air pollution and environmental hazards.                    Air pollution is the 5th largest killer in India by chronic respiratory diseases and asthma. According to the Ministry of Earth Science, October,2018 almost 41% air pollutants in Delhi is vehicular emissions, 21% by dust and 18% is by industries. Moreover , agricultural stubble burning by the farmers,road dust , cold weather and emissions from Badarpur Thermal Power Station are also the key factots of the hazards.                                                There are 5 levels of the A...

          The plants of Carrot Family arrange their flowers in such a way that the main axis or peduncle becomes much shorter and flowers appear to develop from the same point where the older ones are at the periphery and the younger ones are at the center,thus, the inflorescence looks like an umbrella.Hence ,the  family name was given as Umbelliferae.                                                                                                                                      According to the ICBN  each family name should end with the suffix "aceae"added with the legitimate name of a genus included in th...

      Rhizophores are the colourless, aphyllous, elongated and cylindrical appendages which arise from each ramifications i.e.; dichotomy of the prostate leafy stem of Selaginella.             It develops exogenously from the special angle meristem present between the branches of the stem. When it touches the ground, it shows subapical growth with two meristematic zone each one with one root initial and turned into two roots which again form few adventitious roots.                                              There are 3 different viwes about the Morphological Nature of Rhizophores, which are as follows:.                                                              ...

                                                       CALCIUM OXALATE TOXICITY.                                                  A large number of Plants show toxicity due to the deposition of their excretory products like calcium oxalate (Ca C2 O4)in crystal form.                                                                                         The outermost dry scale leaf of onion or tunic contains this chemical in the form of a rod shaped, cubicle shaped (prismatic) colourless crystals . After ...

                                     K (+) Malate Hypothesis of opening and closing of stomata The role of K(+) ion in stomatal opening was first discovered in 1943 by Imamura and suppported and elaborated by Fujino(1967), Lavitt(1974), Raschke(1975),Noggle-Firtz(1976) and it is as follows: IN DAY TIME:  1. In presence of light PEP of guard cells reacts with  carbon dioxide in presence of PEP carboxylase to form OAA.The later is then converted to malic acid and NAD(+) by the activity of malate dehydrogenase. 2. Malic acid is then dissociated into H(+) and Malate(-)ion. 3.In the next step H(+) effluxed from the guard cells due to the activity of H(+) ion pump of guard cell membrane.The malate (-)ion remained in the cell and the cell interior becomes negatively charged and pH of the cell increased avobe 7.0 which helps in more malate synthesis. 4.To balance the ch...