{"id":3741,"date":"2024-05-14T01:28:54","date_gmt":"2024-05-13T19:58:54","guid":{"rendered":"https:\/\/samacheerkalvi.guide\/?p=3741"},"modified":"2024-05-14T15:39:34","modified_gmt":"2024-05-14T10:09:34","slug":"tamil-nadu-11th-biology-model-question-paper-4-english-medium","status":"publish","type":"post","link":"https:\/\/samacheerkalvi.guide\/tamil-nadu-11th-biology-model-question-paper-4-english-medium\/","title":{"rendered":"Tamil Nadu 11th Biology Model Question Paper 4 English Medium"},"content":{"rendered":"

Students can Download Tamil Nadu 11th Biology Model Question Paper 4 English Medium Pdf, Tamil Nadu 11th Biology Model Question Papers<\/a> helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams.<\/p>\n

TN State Board 11th Biology Model Question Paper 4 English Medium<\/h2>\n

General Instructions:<\/p>\n

    \n
  1. \n
      \n
    1. The question paper comprises of\u00a0four<\/span>\u00a0parts. Questions for Botany and Zoology are asked separately.<\/li>\n
    2. You are to attempt all the parts. An internal choice of questions is provided wherever applicable.<\/li>\n
    3. All questions of Part I, II, III and IV are to be attempted separately.<\/li>\n
    4. Question numbers\u00a01<\/span>\u00a0to\u00a08<\/span>\u00a0in\u00a0Part I<\/span>\u00a0are Multiple Choice Questions of\u00a0one mark<\/span>\u00a0each. These are to be answered by choosing the most suitable answer from the given four alternatives and writing the option code and the corresponding answer.<\/li>\n
    5. Question numbers\u00a09<\/span>\u00a0to\u00a014<\/span>\u00a0in\u00a0Part<\/span>\u00a0II<\/span>\u00a0are\u00a0two-marks<\/span>\u00a0questions. These are to be answered in about one or two sentences.<\/li>\n
    6. Question numbers\u00a015<\/span>\u00a0to\u00a019<\/span>\u00a0in\u00a0Part III<\/span>\u00a0are\u00a0three-marks<\/span>\u00a0questions. These are to be answered in about three to five short sentences.<\/li>\n
    7. Question numbers\u00a020<\/span>\u00a0and\u00a021<\/span>\u00a0in\u00a0Part IV<\/span>\u00a0are\u00a0five-marks<\/span>\u00a0questions. These are to be answered in detail. Draw diagrams wherever necessary.<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n

      Time: 3:00 Hours
      \nMaximum Marks: 70<\/p>\n

      Bio – Botany [Maximum Marks: 35]<\/span><\/p>\n

      PART – I<\/span><\/p>\n

      Answer all the questions. Choose the correct answer. [8 \u00d7 1 = 8]<\/span><\/p>\n

      Question 1.
      \nNumber of domains of life are there according to Carl Woese
      \n(a) 3
      \n(b) 2
      \n(c) 4
      \n(d) 5
      \nAnswer:
      \n(a) 3<\/p>\n

      \"Tamil<\/p>\n

      Question 2.
      \nWhich of the following shows coiled RNA strand and capsomeres?
      \n(a) Polio virus
      \n(b) Tobacco mosaic virus
      \n(c) Measles virus
      \n(d) Retrovirus
      \nAnswer:
      \n(b) Tobacco mosaic virus<\/p>\n

      Question 3.
      \nTalipot palm, Bamboo and Agave are examples of …………………….
      \n(a) Polycarpic geophytes
      \n(b) Therophytes
      \n(c) Monocarpic geophytes
      \n(d) Biennial
      \nAnswer:
      \n(c) Monocarpic geophytes<\/p>\n

      \"Tamil<\/p>\n

      Question 4.
      \nThe type of inflorescence seen in Caesalpinia is ………………………
      \n(a) Corymb
      \n(b) Compound corymb
      \n(c) Capitulum
      \n(d) Umbel
      \nAnswer:
      \n(a) Corymb<\/p>\n

      Question 5.
      \nWhich one of the following organism is correctly matched with its three characteristics?
      \n(a) Pea: C3<\/sub> pathway, Endospermic seed,Vexillary aestivation
      \n(b) Tomato: Twisted aestivation, Axile placentation, Berry
      \n(c) Onion: Bulb, Imbricate aestivation, Axile placentation
      \n(d) Maize: C3<\/sub> pathway, Closed vascular bundles, scutellum
      \nAnswer:
      \n(c) Onion: Bulb, Imbricate aestivation, Axile placentation<\/p>\n

      Question 6.
      \nProtoplasm is made of ……………………. water.
      \n(a) 80 – 90%
      \n(b) 85 – 90%
      \n(c) 60 – 80%
      \n(d) 75 – 85%
      \nAnswer:
      \n(c) 60 – 80%<\/p>\n

      Question 7.
      \nThe term soilless culture refers to …………………….
      \n(a) Aeroponics
      \n(b) Aqua culture
      \n(c) Hydroponics
      \n(d) Drip irrigation
      \nAnswer:
      \n(c) Hydroponics<\/p>\n

      \"Tamil<\/p>\n

      Question 8.
      \nWhich of the following statement is NOT true regarding cyclic photophosphorylation?
      \n(a) The primary electron acceptor is FRS
      \n(b) It produces only ATP molecules
      \n(c) It produces only NADPH + H+<\/sup> molecules
      \n(d) Electrons ejected from PSI again cycled back to PSI
      \nAnswer:
      \n(c) It produces only NADPH + H+<\/sup> molecules<\/p>\n

      PART – II<\/span><\/p>\n

      Answer any four of the following questions. [4 \u00d7 2 = 8]<\/span><\/p>\n

      Question 9.
      \nName few plant disease caused by mycoplasma?
      \nAnswer:
      \nLittle leaf of brinjal, witches broom of legumes, phyllody of cloves and sandal spike are some plant diseases caused by mycoplasma.<\/p>\n

      \"Tamil<\/p>\n

      Question 10.
      \nWhich leaf part acts a bridge between leaf & stem? Define?
      \nAnswer:
      \nPetiole is the bridge between leaf and stem. Petiole or leaf stalk is a cylindrical or subcylindrical or flattened structure of a leaf which joins the lamina with the stem.<\/p>\n

      Question 11.
      \nMention any two morphological differences between Dicot & Monocots?
      \nAnswer:<\/p>\n\n\n\n\n\n
      \n

      S.No<\/strong><\/p>\n<\/td>\n

      		\n

      Dicot<\/strong><\/p>\n<\/td>\n

      		\n

      Monocots<\/strong><\/p>\n<\/td>\n<\/tr>\n

      1.<\/td>\nLeaves show reticulate venation<\/td>\nLeaves show parallel venation<\/td>\n<\/tr>\n
      2.<\/td>\nFlowers are tetramerous or pentamerous<\/td>\nFlowers are trimerous<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

      \"Tamil<\/p>\n

      Question 12.
      \nWhat is the cell wall composition of the following organism?<\/p>\n

        \n
      1. Fungi<\/li>\n
      2. Bacteria<\/li>\n
      3. Algae<\/li>\n<\/ol>\n

        Answer:<\/p>\n

          \n
        1. Fungi – Chitin and fungal cellulose<\/li>\n
        2. Bacteria – Peptidoglycan<\/li>\n
        3. Algae – Cellulose, mannan and galactan<\/li>\n<\/ol>\n

          Question 13.
          \nHow imbibition is important for plants?
          \nSignificance of imbibition:
          \nAnswer:<\/p>\n

            \n
          1. During germination of seeds, imbibition increases the volume of seed enormously and leads to bursting of the seed coat.<\/li>\n
          2. It helps in the absorption of water by roots at the initial level.<\/li>\n<\/ol>\n

            \"Tamil<\/p>\n

            Question 14.
            \nHow does nitrogen fixation occurs non – biologically?
            \nNon – Biological nitrogen fixation:
            \nAnswer:<\/p>\n

              \n
            1. Nitrogen fixation by chemical process in industry.<\/li>\n
            2. Natural electrical discharge during lightening fixes atmospheric nitrogen.<\/li>\n<\/ol>\n

              PART – III<\/span><\/p>\n

              Answer any three questions in which question number 19 is compulsory. [3 \u00d7 3 = 9]<\/span><\/p>\n

              Question 15.
              \nName few fungal diseases in Humans?
              \nAnswer:<\/p>\n

              \"Tamil<\/p>\n

              Question 16.
              \nList out any 3 significances of seed?
              \nAnswer:<\/p>\n

                \n
              1. The seed encloses and protects the embryo for next generation.<\/li>\n
              2. Seeds of various plants are used as food, both for animals and human.<\/li>\n
              3. Seeds are the products of sexual reproduction so they provide genetic variations and recombination in a plant.<\/li>\n<\/ol>\n

                \"Tamil<\/p>\n

                Question 17.
                \nWrite a note on endosymbiont theory?
                \nAnswer:
                \nTwo eukaryotic organelles believed to be the descendants of the endosymbiotic prokaryotes. The ancestors of the eukaryotic cell engulfed a bacterium and the bacteria continued to function inside the host cell.<\/p>\n

                Question 18.
                \nWhat are sieve tubes? Explain?
                \nAnswer:
                \nSieve Elements:
                \nSieve elements are the conducting elements of the phloem. They are of two types, namely sieve cells and sieve tubes.<\/p>\n

                Sieve Cells:
                \nThese are primitive type of conducting elements found in Pteridophytes and Gymnosperms. Sieve cdlls have sieve areas on their lateral walls only. They are not associated with companion cells.<\/p>\n

                Sieve Tubes:
                \nSieve tubes are long tube like conducting elements in the phloem. These are formed from a series of cells called sieve tube elements. The sieve tube elements are arranged one above the other and form vertical sieve tube.<\/p>\n

                The end wall contains a number of pores and it looks like a sieve. So it is called as sieve plate. The sieve elements show nacreous thickenings on their lateral walls.<\/p>\n

                They may possess simple or compound sieve plates. The function of sieve tubes are believed to be controlled by campanion cells. In mature sieve tube, Nucleus is absent. It contains a lining layer of cytoplasm.<\/p>\n

                A special protein (P. Protein = Phloem Protein) called slime body is seen in it. In mature sieve tubes, the pores in the sieve plate arc blocked by a substance called callosc (callose plug).<\/p>\n

                The conduction of food material takes place Different types of phloem elements through cytoplasmic strands. Sieve tubes occur only in Angiosperms.<\/p>\n

                \"Tamil<\/p>\n

                \"Tamil<\/p>\n

                Question 19.
                \nDraw and label the structure of lentical?
                \nAnswer:
                \n\"Tamil<\/p>\n

                PART – IV<\/span><\/p>\n

                Answer all the questions. [2 \u00d7 5 = 10]<\/span><\/p>\n

                Question 20.
                \nList out the salient features of cyanobacteria?
                \nAnswer:<\/p>\n

                  \n
                • The members of this group are prokaryotes and lack motile reproductive structures.<\/li>\n
                • The thallus is unicellular in Chroococcus, colonial in Gloeocapsa and filamentous trichome in Nostoc.<\/li>\n
                • Gliding movement is noticed in some species (Oscillatorid).<\/li>\n
                • The protoplasm is differentiated into central region called centroplasm and peripheral region bearing chromatophore called chromoplasm.<\/li>\n
                • The photosynthetic pigments include c – phydcyanin and c – phycoerythrin along with myxoxanthin and myxoxanthophyll.<\/li>\n
                • The reserve food material is cyanophycean starch.<\/li>\n
                • In some forms a large colourless cell is found in the terminal or intercalary position called heterocysts. They are involved in nitrogen fixation.<\/li>\n
                • They reproduce only through vegetative methods and produce akinetes (thick wall dormant cell formed from vegetative cell), hormogonia (a portion of filament get detached and reproduce by cell division), fission and endospores.<\/li>\n
                • The presence of mucilage around the thallus is characteristic feature of this group. Therefore, this group is also called Myxophyceae.<\/li>\n
                • Sexual reproduction is absent.<\/li>\n
                • Microcystis aeruginosa and Anabaena flos – aquae cause water blooms and release toxins and affect the aquatic organism. Most of them fix atmospheric nitrogen and are used as biofertilizers (Example: Nostoc and Anabaena). Spirulina is rich in protein hence it is used as single cell protein.<\/li>\n<\/ul>\n

                  [OR]<\/p>\n

                  Differentiate between Mitosis and Meiosis?
                  \nAnswer:<\/p>\n\n\n\n\n\n\n\n\n\n\n
                  \n

                  Mitosis<\/strong><\/p>\n<\/td>\n

                  		\n

                  Meiosis<\/strong><\/p>\n<\/td>\n<\/tr>\n

                  1. One division<\/td>\n1. Two divisions<\/td>\n<\/tr>\n
                  2. Number of chromosomes remains the same<\/td>\n2. Number of chromosomes is halved<\/td>\n<\/tr>\n
                  3. Homologous chromosomes line up separately on the metaphase plate<\/td>\n3. Homologous chromosomes line up in pairs at the metaphase plate<\/td>\n<\/tr>\n
                  4. Homologous chromosome do not pair up<\/td>\n4. Homologous chromosome pairup to form bivalent<\/td>\n<\/tr>\n
                  5. Chiasmata do not form and crossing over never occurs<\/td>\n5. Chiasmata form and crossingover occurs<\/td>\n<\/tr>\n
                  6. Daughter cells are genetically identical<\/td>\n6. Daughter cells are genetically different from the parent cells<\/td>\n<\/tr>\n
                  7. Two daughter cells are formed<\/td>\n7. Four daughter cells are formed<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                  \"Tamil<\/p>\n

                  Question 21.
                  \nWrite in detail about Passive Absorption of minerals salts?
                  \nAnswer:
                  \nIon-Exchange:
                  \nIons of external soil solution were exchanged with same charged (anion for anion or cation for cation) ions of the root cells. There are two theories explaining this process of ion exchange namely:<\/p>\n

                    \n
                  1. Contact exchange and<\/li>\n
                  2. Carbonic acid exchange.<\/li>\n<\/ol>\n

                    1. Contact Exchange Theory:
                    \nAccording to this theory, the ions adsorbed on the surface of root cells and clay particles (or clay micelles) are not held tightly but oscillate within a small volume of space called oscillation volume. Due to small space, both ions overlap each other\u2019s oscillation volume and exchange takes place.<\/p>\n

                    2. Carbonic Acid Exchange Theory:
                    \nAccording to this theory, soil solution plays an important role by acting as a medium for ion exchange. The CO2<\/sub> released during respiration of root cells combines with water to form carbonic acid (H2<\/sub>CO3<\/sub>).<\/p>\n

                    Carbonic acid dissociates into H+<\/sup> and HCO32<\/sub>–<\/sup> <\/sub>in the soil solution. These H+<\/sup> ions exchange with cations adsorbed on clay particles and the catipns from micelles get released into soil solution and gets adsorbed on root cells.<\/p>\n

                    \"Tamil<\/p>\n

                    \"Tamil<\/p>\n

                    [OR]<\/p>\n

                    Give an detail account on different types of senescence?
                    \nAnswer:
                    \n1. Overall senescence:
                    \nThis kind of senescence occurs in annual plants when entire plant gets affected and dies.
                    \nExample: Wheat and Soybean. It also occurs in few perennials also. Example: Agave and Bamboo.<\/p>\n

                    2. Top senescence:
                    \nIt occurs in aerial parts of plants. It is common in perennials, underground and root system remains viable.
                    \nExample: Banana and Gladiolus.<\/p>\n

                    3. Deciduous senescence:
                    \nIt is common in deciduous plants and occurs only in leaves of plants, bulk of the stem and root system remains alive.
                    \nExample: Elm and Maple.<\/p>\n

                    4. Progressive senescence:
                    \nThis kind of senescence is gradual. First it occurs in old leaves followed by new leaves then stem and finally root system. It is common in annuals.<\/p>\n

                    Bio – Zoology [Maximum Marks: 35]<\/span><\/p>\n

                    PART – I<\/span><\/p>\n

                    Answer all the questions. Choose the correct answer. [8 \u00d7 1 = 8]<\/span><\/p>\n

                    Question 1.
                    \nTrue species are …………………….
                    \n(a) Inter breeding
                    \n(b) Sharing the same niche
                    \n(c) Reproductively isolated
                    \n(d) Feeding on the same food
                    \nAnswer:
                    \n(c) Reproductively isolated<\/p>\n

                    \"Tamil<\/p>\n

                    Question 2.
                    \nCollar cells are found in ……………………
                    \n(a) Aschelminthes
                    \n(b) Sponges
                    \n(c) Cnidaria
                    \n(d) Arthropoda
                    \nAnswer:
                    \n(b) Sponges<\/p>\n

                    Question 3.
                    \nMatch the List – I and List – II.<\/p>\n\n\n\n\n\n\n\n
                    \n

                    List – \u00a0I<\/strong><\/p>\n<\/td>\n

                    		\n

                    List – II<\/strong><\/p>\n<\/td>\n<\/tr>\n

                    1. Adenohypopysis<\/td>\n(i) Epinephrine<\/td>\n<\/tr>\n
                    2. Adrenal medulla<\/td>\n(ii) Somatotropin<\/td>\n<\/tr>\n
                    3. Parathyroid gland<\/td>\n(iii) Thymosin<\/td>\n<\/tr>\n
                    4. Thymus gland<\/td>\n(iv) Calcitonin<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                    Answer:
                    \n(a) 1 – (i), 2 – (ii), 3 – (iii), 4 – (iv)
                    \n(b) 1 – (ii), 2 – (i), 3 – (iv), 4 – (iii)
                    \n(c) 1 – (iii), 2 – (i), 3 – (iv), 4 – (ii)
                    \n(d) 1 – (iv), 2 – (iii), 3 – (ii), 4 – (i)<\/p>\n

                    \"Tamil<\/p>\n

                    Question 4.
                    \nBMR stands for ……………………….
                    \n(a) Body matabolic rate
                    \n(b) Basal matabolic rate
                    \n(c) Body mass rate
                    \n(d) Basal mass rate
                    \nAnswer:
                    \n(b) Basal matabolic rate<\/p>\n

                    Question 5.
                    \nWhich of the following statement is correct ………………………….
                    \n(a) Testosterone is produced by leyding cells under the influence Luteinizing hormone.
                    \n(b) Progesterorie is secreted by corpus luteum.
                    \n(c) Oestrogen is secreted by Sertolic cells.
                    \n(d) Progesterone produced by Corpus Luteum is biologically different from the one produced by placenta.
                    \nAnswer:
                    \n(a) Testosterone is produced by leyding cells under the influence Luteinizing hormone.<\/p>\n

                    \"Tamil<\/p>\n

                    Question 6.
                    \nWhich of the following pair statement is incorrect?
                    \n(a) Humans – ureotelic
                    \n(b) Birds – uricotelic
                    \n(c) Lizards – uricotelic
                    \n(d) Whale – Ammonotelic
                    \nAnswer:
                    \n(d) Whale – Ammonotelic<\/p>\n

                    Question 7.
                    \nInflammation of joints due to accumulation of uric acid crystals is called as ………………………..
                    \n(a) Myasthenia gravis
                    \n(b) Gout
                    \n(c) Osteoporosis
                    \n(d) Osteomalacia
                    \nAnswer:
                    \n(b) Gout<\/p>\n

                    \"Tamil<\/p>\n

                    Question 8.
                    \nThe olfactory umpulses are transmitted to the ………………………. lobe of brain.
                    \n(a) Parietal
                    \n(b) Temporal
                    \n(c) Occipital
                    \n(d) Frontal
                    \nAnswer:
                    \n(d) Frontal<\/p>\n

                    PART – II<\/span><\/p>\n

                    Answer any four of the following questions. [4 \u00d7 2 = 8]<\/span><\/p>\n

                    Question 9.
                    \nWhat is Regeneration?
                    \nAnswer:
                    \nThe ability to regrow the lost parts is called regeneration eg. planaria.<\/p>\n

                    Question 10.
                    \nWhat are the functions of Tapetum lucidum?
                    \nAnswer:
                    \nA reflective layer of tissue called tapetum lucidum, enhances night time vision in most of the animals like cat.<\/p>\n

                    \"Tamil<\/p>\n

                    Question 11.
                    \nGive an example for longest species of earthworm?
                    \nAnswer:
                    \nMicrochaetus rappi is an African giant earthworm, can reach a length of 6.7 meter (22 feet). Drawida nilamburansis is a south Indian (Kerala) species of earthworm and can reach a maximum length up to f meter (3 feet).<\/p>\n

                    Question 12.
                    \nDifferences between frog and toad?
                    \nAnswer:<\/p>\n

                    \"Tamil<\/p>\n

                    Question 13.
                    \nBrief notes on spinal nerves?
                    \nAnswer:
                    \nSpinal nerves:
                    \n31 pairs of spinal nerves emerge out from the spinal cord through spaces called the intervertebral foramina found between the adjacent vertebrae. The spinal nerves are named according to the region of vertebral column from which they originate<\/p>\n

                      \n
                    1. Cervical nerves (8 pairs)<\/li>\n
                    2. Thoracic nerves (12 pairs)<\/li>\n
                    3. Lumbar nerves (5 pairs)<\/li>\n
                    4. Sacral nerves (5 pairs)<\/li>\n
                    5. Coccygeal nerves (1 pair)<\/li>\n<\/ol>\n

                      Each spinal nerve is a mixed nerve containing both afferent (sensory) and efferent (motor) fibres. It originates as two roots:<\/p>\n

                        \n
                      1. A posterior dorsal root with a ganglion outside the spinal cord and<\/li>\n
                      2. An anterior ventral root with no external ganglion.<\/li>\n<\/ol>\n

                        \"Tamil<\/p>\n

                        Question 14.
                        \nDraw the structure of Nephron?
                        \nAnswer:<\/p>\n

                        \"Tamil<\/p>\n

                        PART – III<\/span><\/p>\n

                        Answer any three questions in which question number 19 is compulsory. [3 \u00d7 3 = 9]<\/span><\/p>\n

                        Question 15.
                        \nWhat is phylogenetic classification or cladistics?
                        \nAnswer:
                        \nThe classification of organisms based on evolutionary and genetic relationship among them is known as phylogenetic classification.<\/p>\n

                        \"Tamil<\/p>\n

                        Question 16.
                        \nCompare Schizocoelom with Enterocoelom?
                        \nAnswer:<\/p>\n\n\n\n\n\n
                        \n

                        Schizocoelom<\/strong><\/p>\n<\/td>\n

                        		\n

                        Enterocoelom<\/strong><\/p>\n<\/td>\n<\/tr>\n

                        1. The coelom which is formed by splitting of mesoderm is called Schizocoelom.<\/td>\n1. The coelom which is formed from the mesodermal pouches of archenteron is called entercoelom.<\/td>\n<\/tr>\n
                        2. It is found in lower vertebrates like annelids, arthopods, molluscs.<\/td>\n2. It is found in echinodermis, hemichordates and chordates.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                        Question 17.
                        \nHead of cockroach is called hypognathous. why?
                        \nAnswer:
                        \nThe mouth parts of cockroach are directed downwards. The head is small, triangular lies at right angle to the longitudinal body axis. Hence it is called hypognatus.<\/p>\n

                        Question 18.
                        \nDraw the diagram and label the parts of micro villi?
                        \nAnswer:<\/p>\n

                        \"Tamil<\/p>\n

                        \"Tamil<\/p>\n

                        Question 19.
                        \nWhat are the advantages of artificial insemination?
                        \nAnswer:<\/p>\n

                          \n
                        1. It increases the rate of conception<\/li>\n
                        2. It avoids genital diseases<\/span><\/li>\n
                        3. Semen can be collected from injured bulls which have desirable traits<\/span><\/li>\n
                        4. Superior animals located apart can be bred successfully<\/span><\/li>\n<\/ol>\n

                          PART – IV<\/span><\/p>\n

                          Answer all the questions. [2 \u00d7 5 = 10]<\/span><\/p>\n

                          Question 20.
                          \nWrite brief notes on Diploblastic and Triploblastic organisation with example?
                          \nAnswer:
                          \nDuring embryonic development, the tissues and organs of animals originate from two or three embryonic germ layers. On the basis of the origin and development, animals are classified into two categories: Diploblastic and Triploblastic.<\/p>\n

                          Animals in which the cells are arranged in two embryonic layers, the external ectoderm, and internal endoderm are called diploblastic animals. In these animals the ectoderm gives rise to the epidermis (the outer layer of the body wall) and endoderm gives rise to gastrodermis (tissue lining the gut cavity). An undifferentiated layer present between the ectoderm and endoderm is the mesoglea. (Corals, Jellyfish, Sea anemone)<\/p>\n

                          Animals in which the developing embryo has three germinal layers are called triploblastic animals and consists of outer ectoderm (skin, hair, neuron, nail, teeth, etc), inner endoderm (gut, lung, liver) and middle mesoderm (muscle, bone, heart). Most of the triploblastic animals show organ system level of organisation (Flat worms to Chordates).<\/p>\n

                          [OR]<\/p>\n

                          Explain the reproductive system of frog?
                          \nAnswer:
                          \nReproductive system:
                          \nThe male frog has a pair of testes which are attached to the kidney and the dorsal body wall by folds of peritonium called mesorchium. Vasa efferentia arise from each testis. They enter the kidneys on both side and open into the bladder canal. Finally, it communicates with the urinogenital duct that comes out of kidneys and opens into the cloaca.<\/p>\n

                          Female reproductive system consists of paired ovaries, attached to the kidneys, and dorsal body wall by folds of peritoneum called mesovarium. There is a pair of coiled oviducts lying on the sides of the kidney. Each oviduct opens into the body-cavity at the anterior end by a funnel like opening called ostia.<\/p>\n

                          Unlike the male frog, the female frog has separate genital ducts distinct from ureters. Posteriorly the oviducts dilated to form ovisacs before they open into cloaca. Ovisacs store the eggs temporarily before they are sent out through the cloaca. Fertilization is external.<\/p>\n

                          Within few days of fertilization, the eggs hatch into tadpoles. A newly hatched tadpole lives off the yolk stored in its body. It gradually grows larger and develops three pairs of gills.<\/p>\n

                          The tadpole grows and metamorphosis into an air – breathing carnivorous adult frog. Legs grow from the body, and the tail and gills disappear. The mouth broadens, developing teeth and jaws, and the lungs become functional.<\/p>\n

                          \"Tamil<\/p>\n

                          Question 21.
                          \nWhat are the disorders related to the excretory system?
                          \nAnswer:
                          \nUrinary tract infection:
                          \nFemale\u2019s urethra is very short and its external opening is close to the anal opening, hence improper toilet habits can easily carry faecal bacteria into the urethra. The urethral mucosa is continuous with the urinary tract and the inflammation of the urethra (urethritis) can ascend the tract to cause bladder inflammation (cystitis) or even renal inflammation (pyelitis or pyelonephritis).<\/p>\n

                          Symptoms include dysuria (painful urination), urinary urgency, fever and sometimes cloudy or blood tinged urine. When the kidneys are inflammed, back pain and severe headache often occur. Most urinary tract infections can be treated by antibiotics.<\/p>\n

                          Renal Failure (Kidney Failure):
                          \nFailure of the kidneys to excrete wastes may lead to accumulation of urea with marked reduction in the urine output. Renal failure are of two types, Acute and chronic renal failure.<\/p>\n

                          In acute renal failure the kidney stops its function abruptly, but there are chances for recovery of kidney functions. In chronic renal failure there is a progressive loss of function of the nephrons which gradually decreases the function of kidneys.<\/p>\n

                          Uremia:
                          \nUremia is characterized by increase in urea and other non – protein nitrogenous substances like uric acid and creatinine in blood. Normal urea level in human blood is about 17 – 30mg\/100mL of blood. The urea concentration rises as 10 times of normal levels during chronic renal failure.<\/p>\n

                          Renal calculi:
                          \nRenal calculi, also called renal stone or kidney stone or nephrolithiasis, is the formation of hard stone like masses in the renal tubules of renal pelvis.<\/p>\n

                          It is mainly due to the accumulation of soluble crystals of salts of sodium oxalates and certain phosphates. This result in severe pain called \u201crenal colic pain\u201d and can cause scars in the kidneys. Renal stones can be removed by techniques like pyleothotomy or lithotripsy.<\/p>\n

                          Glomerulonephritis:
                          \nIt is also called Bright\u2019s disease and is characterized by inflammation of the glomeruli of both kidneys and is usually due to post-streptococcal infection that occurs in children. Symptoms are haematuria, proteinuria, salt and water retention, oligouria, hypertension and pulmonary oedema.<\/p>\n

                          [OR]<\/p>\n

                          Describe the life cycle of Bombyx mori?
                          \nAnswer:
                          \nLife cycle of Bombyx mori:
                          \nThe adult of Bombyx mori is about 2.5 cm in length and pale creamy white in colour. Due to heavy body and feeble wings, flight is not possible by the female moth.<\/p>\n

                          This moth is unisexual in nature and does not feed during its very short life period of 2 – 3 days. Just after emergence, male moth copulates with female for about 2 – 3 hours and if not separated, they may die after few hours of copulating with female.<\/p>\n

                          Just after copulation, female starts egg laying which is completed in 1-24 hours. A single female moth lays 400 to 500 eggs depending upon the climatic conditions.<\/p>\n

                          Two types of eggs are generally found namely diapause type and non-diapause type. The diapause type is laid by silkworms inhabiting the temperate regions, whereas silkworms belonging to subtropical regions like India lay non – diapause type of eggs.<\/p>\n

                          The eggs after ten days of incubation hatch into larva called as caterpillar. The newly hatched caterpillar is about 3 mm in length and is pale, yellowish-white in colour. The caterpillars are provided with well developed mandibulate type of mouth-parts adapted to feed easily on the mulberry leaves.<\/p>\n

                          After 1st<\/sup>, 22nd<\/sup>, 3rd<\/sup> and 4th<\/sup> moultings caterpillars get transformed into 2nd<\/sup>, 3rd<\/sup>, 4th<\/sup> and 5th<\/sup> instars respectively. It takes about 21 to 25 days after hatching. The fully grown caterpillar is 7.5 cm in length. It develops salivary glands, stops feeding and undergoes pupation.<\/p>\n

                          The caterpillars stop feeding and move towards the comer among the leaves and secretes a sticky fluid through their silk gland. The secreted fluid comes out through spinneret (a narrow pore situated on the hypopharynx) and takes the form of long fine thread of silk which hardens on exposure to air and is wrapped around the body of caterpillar in the forms of a covering called as cocoon.<\/p>\n

                          It is the white coloured bed of the pupa whose outer threads are irregular while the inner threads are regular. The length of continuous thread secreted by a caterpillar for the formation of cocoon is about 1000 – 1200 metres which requires 3 days to complete. The pupal period lasts for 10 to 12 days and the pupae cut through the cocoon and emerge into adult moth.<\/p>\n","protected":false},"excerpt":{"rendered":"

                          Students can Download Tamil Nadu 11th Biology Model Question Paper 4 English Medium Pdf, Tamil Nadu 11th Biology Model Question Papers helps you to revise the complete Tamilnadu State Board New Syllabus, helps students complete homework assignments and to score high marks in board exams. TN State Board 11th Biology Model Question Paper 4 English …<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[6],"tags":[],"class_list":["post-3741","post","type-post","status-publish","format-standard","hentry","category-class-11"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts\/3741"}],"collection":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/comments?post=3741"}],"version-history":[{"count":1,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts\/3741\/revisions"}],"predecessor-version":[{"id":40168,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts\/3741\/revisions\/40168"}],"wp:attachment":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/media?parent=3741"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/categories?post=3741"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/tags?post=3741"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}