{"id":90127,"date":"2021-07-23T14:18:13","date_gmt":"2021-07-23T08:48:13","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=90127"},"modified":"2021-07-23T14:18:13","modified_gmt":"2021-07-23T08:48:13","slug":"1st-puc-biology-previous-year-question-paper-march-2014-south","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/1st-puc-biology-previous-year-question-paper-march-2014-south\/","title":{"rendered":"1st PUC Biology Previous Year Question Paper March 2014 (South)"},"content":{"rendered":"

Students can Download 1st PUC Biology Previous Year Question Paper March 2014 (South), Karnataka 1st PUC Biology Model Question Papers with Answers<\/a> helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.<\/p>\n

Karnataka 1st PUC Biology Previous Year Question Paper March 2014 (South)<\/h2>\n

Time: 3.15 Hours
\nMax Marks: 70<\/p>\n

General Instructions:<\/p>\n

    \n
  1. The question paper consists of four parts A, B, C, and D.<\/li>\n
  2. All the parts are compulsory.<\/li>\n
  3. Draw diagrams wherever necessary. Unlabelled diagrams or illustrations do not attract any marks.<\/li>\n<\/ol>\n

    Part – A<\/span><\/p>\n

    Answer the following questions in one word \/ one sentence each: ( 10 \u00d7 1 = 10 )<\/span><\/p>\n

    Question 1.
    \nIn which group of algae, red pigment r-phycoerythrin is present?
    \nAnswer:
    \nRhodophyta,<\/p>\n

    Question 2.
    \nWrite the biological name of potato.
    \nAnswer:
    \nSolanum tuberosum.<\/p>\n

    Question 3.
    \nDefine mesophyll tissue.
    \nAnswer:
    \nPhotosynthetic tissue present between upper and lower epidermis of leaf is mesophyll.<\/p>\n

    Question 4.
    \nName the bond present between monosaccharides in a polysaccharide.
    \nAnswer:
    \nGlycosidic bond.<\/p>\n

    Question 5.
    \nWrite the energy currency of the cell.
    \nAnswer:
    \nATP.<\/p>\n

    \"KSEEB<\/p>\n

    Question 6.
    \nDefine imbibition.
    \nAnswer:
    \nImbibition is a special kind of diffusion that involves the movement of water molecules along a diffusion gradient from a region of higher concentration onto a suitable solid matrix (adsorption).
    \nor
    \nIt is the adsorption of water molecules by hydrophilic colloids.<\/p>\n

    Question 7.
    \nDefine hydroponics.
    \nAnswer:
    \nThe technique of growing plants in a nutrient solution is known as hydroponics.<\/p>\n

    Question 8.
    \nMention the normal blood pressure in humans.
    \nAnswer:
    \n120\/80 mm of Hg.<\/p>\n

    Question 9.
    \nWhere is the pituitary gland located?
    \nAnswer:
    \nSella tunica (bony caving) is attached to the hypothalamus.<\/p>\n

    Question 10.
    \nMention the function of the pericardium.
    \nAnswer:
    \nIt provides protection to the heart.<\/p>\n

    PART-B<\/span><\/p>\n

    Answer any FIVE of the following questions in 3-5 sentences each, wherever applicable. (5 \u00d7 2 = 10)<\/span><\/p>\n

    Question 11.
    \nClassify the bacteria based on their shape.
    \nAnswer:
    \nBacteria are the smallest and most primitive cellular organisms. They are microscopic and often regarded as germs.<\/p>\n

    Bacteria are cosmopolitan in distribution and found in all environments i.e, soil, air, and water. They also occur in plants and animals, both in living and dead.<\/p>\n

    Bacteria are unicellular organisms and they exist in various forms (shapes).<\/p>\n

    Four major forms of bacteria exist in nature.
    \n1. Coccus form: These are spherical in shape. Cocci forms may occur singly, in pairs, in a clamp or in chains. Accordingly, they are named as:<\/p>\n

      \n
    • Gonococcus: Occur singly (Micrococcus).<\/li>\n
    • Diplococcus: Occur in pairs (Diplococcus pneumonia).<\/li>\n
    • Staphylococcus: Occur in groups (Streptococcus pyro genes).<\/li>\n<\/ul>\n

      2. Bacillus form: These are rod-shaped. They may occur singly, in pairs, or in chains. i.e. Bacillus, Diplohacilli, Streptobaci III.<\/p>\n

      3. Spinllum form: These bacteria have spirally coiled bodies. eg: Treponema Rhodo spirillum.<\/p>\n

      4. Vibrio form: These are comma-shaped. eg: VI brio Cholerae.<\/p>\n

      \"KSEEB<\/p>\n

      Question 12.
      \nWrite the excretory organs of
      \n(i) Arthropods
      \n(ii) class Mammalia.
      \nAnswer:
      \n(i) Malpighian tubules and green glands
      \n(ii) Metanephric kidneys.<\/p>\n

      Question 13.
      \nWrite short notes on epithelial tissue.
      \nAnswer:
      \nThe four main characteristic features are:
      \n(a) The cells are arranged compactly, without interce\u00cdlular spaces.
      \n(b) Epithelial cells always rest on the basement membrane composed of fine fibers and non-living protein-polysaccharide material.
      \n(c) The cells are arranged in the form of a continuous layer or sheet. Such a sheet may cover the external surface of an organ or internal cavity.
      \n(d) The cells may be grouped as tubes or follicles to produce glands.
      \n(e) Epithelial tissues are avascular.<\/p>\n

      Question 14.
      \nGive any four examples for secondary metabolites.
      \nAnswer:
      \nPigments, Alkaloids, Essential oils, Toxins. …….<\/p>\n

      Question 15.
      \nMention any four forms of essential nutrient elements.
      \nAnswer:<\/p>\n

        \n
      1. Components of biomolecules energy-related molecules.<\/li>\n
      2. Components of energy-related molecules.<\/li>\n
      3. Act as enzyme regulators.<\/li>\n
      4. Act as osmotic potential regulators in the cytoplasm.<\/li>\n<\/ol>\n

        Question 16.
        \nList the different types of valves present in the human heart
        \nAnswer:
        \nSemilunar, tricuspid and bicuspid valves.<\/p>\n

        \"KSEEB<\/p>\n

        Question 17.
        \nWrite any four characters of skeletal muscles.
        \nAnswer:
        \nSkeletal muscle:<\/p>\n

          \n
        1. It occurs in limbs, neck, trunk, etc.<\/li>\n
        2. Each fiber contains a number of nuclei just below sarcolemma.<\/li>\n
        3. Muscle fibers are unbranched and run parallel.<\/li>\n
        4. Cross bands are distinct.<\/li>\n
        5. It is voluntary in function.<\/li>\n
        6. They suffer fatigue.<\/li>\n<\/ol>\n

          Question 18.
          \nWrite short notes : (a) Gout (b) Tetany.
          \nAnswer:
          \nTetany: Rapid spasms (wild contractions) in muscle due to low Ca+2<\/sup> in body fluids.
          \nGout: Inflammation of joints due to accumulation of uric acid crystals.<\/p>\n

          PART-C<\/span><\/p>\n

          Answer any FIVE of the following questions in 40-80 words each, wherever applicable: (5 \u00d7 3 = 15)<\/span><\/p>\n

          Question 19.
          \nWho proposed the five-kingdom classification? Write the names of five kingdoms.
          \nAnswer:
          \nR.H. Whittaker.<\/p>\n

            \n
          1. Kingdom monera<\/li>\n
          2. Kingdom Protista<\/li>\n
          3. Kingdom Mycota<\/li>\n
          4. Kingdom Animalia<\/li>\n
          5. Kingdom Plantae.<\/li>\n<\/ol>\n

            Question 20.
            \nDefine the following:
            \n(a) Hypogynous flower
            \n(b) Phyllotaxy
            \n(c) Venation
            \nAnswer:
            \nHypogynous flower: A flower possessing a superior ovary.
            \nPhyllotaxy: The mode of arrangement of leaves on the stem axis is known as phyllotaxy.
            \nVenation: The mode of arrangement of veins and veinlets is called venation.<\/p>\n

            Question 21.
            \nExplain the structure of Stomata.
            \nAnswer:
            \n\"1st<\/p>\n

            Question 22.
            \nWhat are chromosomes? Classify the chromosomes based on the position of the centromere.
            \nAnswer:
            \nChromosomes: Chr\u00f3mosomes are the thread-like colored bodies that are in the intranuclear position which act as the vehicles of heredity and variations.<\/p>\n

            They are self-replicating and exhibit cyclic changes in size and shape. They are visible during cell division: Waldeyer described them in 1888.<\/p>\n

            Chromosomes are the self-reproducing components of the nucleus with DNA, which become visible during cell division. They exhibit a cyclic change in size & shape.<\/p>\n

            1. Chromosom size: The size \u2018of the chromosomes measured a the metaphase of mitosis. It is constant for a particular species. Its length varies from 0.2 to 5.2. Diameter 0.2 to 2i. Chromosomes of plants are larger than that of animals. Monocots have very large ones. The more the number of chromosomes per nu\u00e7ieus, the smaller is the size, the lesser the number bigger in size, the Example for large chromosomes. Oocytes of vertebrates – Lampbrush chromosomes, Insects – Salivary gland or polytene.<\/p>\n

            2. Chromosome shape: Shape changes with that of the stage of cell division. In interphase, it is chromatin & thin thread-like, but long and slender in prophase.<\/p>\n

            Chromomeres: The bead-like swelling of prophase chromosomes is called chromomeres. They become thick during metaphase.
            \n\"1st
            \nTypes of Chromosomes:
            \nI. Classification of chromosomes based on the number of centromeres:
            \n(a) Acentric chromosome: It is a chromosome without centromere.
            \n(b) Monocentric chromosome: Here there is one centromere to hold the chromatids together.
            \n(c) Biceiitric chromosome: It is the presence of two centromeres in a chromosome.
            \n(d) Polycentric chromosome: It is more than three centromeres in a chromosome.<\/p>\n

            II. Classification of chromosomes based on the position of centromere:
            \n(a) Metacentrie type: Here the centromere is exactly at the center of two chromatids. It looks V-shaped during anaphase.
            \n(b) Sub metacentric type: Here the \u2018centromere is eccentric iii positions so that one of the chromatids is long and the other is shorter. It looks L – shaped during anaphase.
            \n(c) Acrocentric type: Here the centromere is almost towards one end of the chromatid to form a very long arm and another very short arm. It looks hook-shaped during anaphase.
            \n(d) Telocentric type: Here the centromere is towards one end of the chromatid such that one chromatid is only present. It looks rod-shaped during anaphase.
            \n\"1st
            \nIII. Classification of chromosomes based on their functions:
            \n(a) Autosomes[AA]: They are also called somatic chromosomes that control body characteristics.
            \n(b) Allosomes X or VI: They are also called sex chromosomes that determine the gender of an individual.<\/p>\n

            Functions of chromosomes:<\/p>\n

              \n
            1. Chromosomes are very important in the higher animals for the phenomenon of sex determination.<\/li>\n
            2. Chromosomes play an active role in the metabolic process of a cell.<\/li>\n
            3. They carry the heredity information from parents to offspring \u00a1n the form of genes.<\/li>\n<\/ol>\n

              \"KSEEB<\/p>\n

              Question 23.
              \nWrite the schematic representation of the nitrogen cycle
              \nAnswer:
              \nNitrogen Cycle:
              \n1. Nitrogen is a limiting nutrient for both natural, and agricultural ecosystems.<\/p>\n

              2. It exists as two nitrogen atoms held together by strong triple covalent bonds (N = N).<\/p>\n

              3. The nitrogen cycle involves the following steps:<\/p>\n

                \n
              1. Nitrogen fixation<\/li>\n
              2. Ammonification<\/li>\n
              3. Nitrification and<\/li>\n
              4. Denitrification.<\/li>\n<\/ol>\n

                1. Nitrogen Fixation:<\/p>\n

                  \n
                • The process of conversion of nitrogen into ammonia and\/or other nitrogen compounds is known as nitrogen fixation.<\/li>\n
                • In nature, lighting and ultraviolet radiation provide energy, to convert nitrogen into nitrogen compounds like N2<\/sub>O, NO, and NO2<\/sub>.<\/li>\n
                • The atmosphere also gets some amount of nitrogen oxides from forest fires, automobile exhausts, industrial combustion, and power generating stations.<\/li>\n<\/ul>\n

                  2. Ammonification:<\/p>\n

                    \n
                  • The process by which organic nitrogenous compounds arc decomposed to produce ammonia is known as ammonification.<\/li>\n
                  • Some ammonia volatilizes and re-enters the atmosphere.<\/li>\n
                  • Most of the ammonia is converted into nitrites and nitrates.<\/li>\n<\/ul>\n

                    \"1st
                    \n3. Nitrification:<\/p>\n

                      \n
                    • Nitrification is the process of converting ammonia first into nitrite, and then into nitrate.
                      \n2NH + 3O2<\/sub> \u2192 2NO2<\/sub> + 2H+<\/sup> + 2H2<\/sub>O
                      \n2NO2<\/sub> + O2<\/sub> \u2192 2NO3<\/sub><\/li>\n
                    • These processes are carried out by soil bacteria that are chemoautotrophs.<\/li>\n
                    • Ammonia is oxidized into nitrite by Nitrosomonas and Nitrococcus.<\/li>\n
                    • Nitrite is oxidized to nitrate by Nitrobacter,<\/li>\n
                    • The nitrates are absorbed by the plants. and reduced to nitrites.<\/li>\n
                    • The nitrites are transported to the leaves and reduced to ammonia, which forms the amino group of amino acids.<\/li>\n<\/ul>\n

                      4. Denitnfication :<\/p>\n

                        \n
                      • It is the process of conversion or reduction of nitrates into free nitrogen.<\/li>\n
                      • It is carried out by bacteria like Pseudomonas and Thiobacillus.<\/li>\n<\/ul>\n

                        Question 24.
                        \nBriefly explain any two disorders of the digestive system.
                        \nAnswer:
                        \nJaundice [Icterus]:
                        \nIt is the most common digestive disorder. Jaundice relates to the yellow appearance of skin, urine, nails, and cornea of the eye due to an increased Bilirubin pigment (Bile pigment).<\/p>\n

                        Jaundice is of three types:
                        \n1. Haemolytic Jaundice or Neonatal Jaundice or Pre hepatic Jaundice: It is commonly found in newly born babies up to one week of age. it is due to excessive hemolysis (Destruction of RBCs).<\/p>\n

                        2. Infective or Hepatocellular Jaundice: It is due to the infection of the hepatitis virus of the liver. So, the liver becomes unable to process Bilirubin. It results in a heavy accumulation of Bilirubin which leads to Hepatocellular Jaundice.<\/p>\n

                        3. Obstructive Jaundice or Extra Hepatic jaundice: It occurs due to the obstruction in the Bile duct. The obstruction of the Bile duct is due to gallstone formation. The bile duct \u00a1s thus blocked, and bile juice cannot enter into the duodenum.<\/p>\n

                        Causes:<\/p>\n

                          \n
                        1. Liver damage due to viral infection, and consumption of alcohol.<\/li>\n
                        2. Increased Bilirubin pigment in the body.<\/li>\n
                        3. Excessive hemolysis.<\/li>\n
                        4. Blockage of the bile duct due to gallstone.<\/li>\n
                        5. Presence of tumors in the bile duct.<\/li>\n<\/ol>\n

                          Effects:<\/p>\n

                            \n
                          1. Yellow coloration of the skin, eyes, and urine.<\/li>\n
                          2. Fever, loss of appetite, nausea, vomiting, and headache.<\/li>\n
                          3. Infective jaundice leads to bleeding, and shrinkage of the liver [Cirrhosis]<\/li>\n
                          4. Unconsciousness and finally it may lead to death.<\/li>\n<\/ol>\n

                            Prevention:
                            \nIt can be prevented by avoiding the consumption of alcohol and also by avoiding the consumption
                            \nof contaminated food and water.<\/p>\n

                            Treatment :<\/p>\n

                              \n
                            1. Vaccines and anti-viral drugs are used against infective jaundice.<\/li>\n
                            2. Obstructive jaundice can be treated by surgery.<\/li>\n<\/ol>\n

                              Question 25.
                              \nShow the diagrammatic representation of the exchange of gases between alveoli and blood.
                              \nAnswer:
                              \n\"1st<\/p>\n

                              Question 26.
                              \nDiscuss briefly the functions on PCT, Henle’s loop, and DCT.
                              \nAnswer:
                              \nProximal convoluted tubule (PCT) :
                              \nIt is a highly coiled twisted tube. his lined by a brush bordered cuboidal epithelial cells. Selective reabsorption of essential substances takes place in PCT during urine formation.<\/p>\n

                              Distal convoluted tubule (DCT) :
                              \nThe ascending limb of Henle\u2019s loop is continued with DCT. It is lined by cuboidal epithelium.<\/p>\n

                              It is less coiled and broader than PCE Active secretion of certain ions and water from the blood takes place in this region. Collecting duct: It is a straight tube lined with columnar epithelium.<\/p>\n

                              Several collecting ducts open into the larger tubule which in turn opens into the pelvis of the Kidney. It also reabsorbs water and Na+ ions from the urine.<\/p>\n

                              Part-D (Section – I).<\/span><\/p>\n

                              I. Answer any FOUR of the following questions in 200-250 words each. (4 \u00d7 5 = 20)<\/span><\/p>\n

                              Question 27.
                              \nAnswer the following.
                              \n(a) State the law of limiting factors
                              \nAnswer:
                              \nBlackman’s Law of Limiting Factors:
                              \nThe law states that \u201cWhen a process is conditioned to its rapidity by the number of separate factors the role of the process is limited by the pace of the slowest factor\u201d.<\/p>\n

                              (b) Discuss the various factors affecting photosynthesis.
                              \nAnswer:
                              \nFactors affecting photosynthesis:
                              \nThe following factors influence photosynthesis:
                              \n1. Light: Sunlight \u00a1s used as a primary source of energy. Its three aspects affecting the process are:
                              \n(a) Light Intensity: Optimum light intensity for photosynthesis is 2000-2500 foot candles\/ Higher light intensity bleaches chlorophyll and is called solarisation.
                              \n(b) Light Quality: Photosynthetic rate is maximum in red light, next maximum in blue light, and least in green light.
                              \n(c) Duration: Phot\u00f3synthetic rate is more efficient in intermittent light than in continuous light supply.<\/p>\n

                              2. CO2<\/sub>: Used as a raw material in photosynthesis. Its concentration in air is 0.03%. Its increase up to 0.5% increases the rate of the process but above 0.5% inhibits photosynthesis.<\/p>\n

                              3.O2<\/sub>: Liberated as a by-product in photosynthesis. its increase above the normal 21% in air, decreases the rate of the process. It is called the Warburg effect.<\/p>\n

                              4. Temperature: It affects photosynthesis through its influence on the enzyme-controlled dark reaction. The optimum temperature is 18 – 400C for photosynthesis.<\/p>\n

                              5. Water: Used as a raw material in photosynthesis. In the dehydrated state of cells, photosynthesis is inhibited.<\/p>\n

                              Question 28.
                              \nWrite the schematic representation of glycolysis.
                              \nAnswer:
                              \nIt occurs in the c\u00fdtoplasm of the cell.
                              \nIt is an enzymatic reaction, thus temperature sensitive.
                              \nIt is a common reaction for both aerobic and anaerobic respiration.
                              \n\"1st<\/p>\n

                              \"KSEEB<\/p>\n

                              Question 29.
                              \nDraw a neat labeled diagram of the digestive system of cockroaches.
                              \nAnswer:
                              \n\"1st<\/p>\n

                              Question 30.
                              \nWhat are auxins? List any four applications of auxins.
                              \nAnswer:
                              \nAuxins:<\/p>\n

                                \n
                              • Auxins were the first hormones to be discovered in plants.<\/li>\n
                              • F.W. Went confirmed and isolated the auxins from coleoptiles of Avena saliva.<\/li>\n
                              • Chemically it is called indole-3-Acetic Acid and is derived from amino acid tryptophan.<\/li>\n
                              • Auxins can stimulate cell division, cell elongation, and cell maturation.<\/li>\n
                              • It promotes Apical dominance.<\/li>\n
                              • It initiates Root formation.<\/li>\n
                              • Can promote parthenocarpy.<\/li>\n
                              • Prevent premature fall of flowers, buds, and leaves,<\/li>\n
                              • 2, 4D, and 2, 4, 5T are used as selective weedicides.<\/li>\n
                              • Promote phototrophic and hydrotropic movements.<\/li>\n
                              • Promote xylem differentiation.<\/li>\n<\/ul>\n

                                Question 31.
                                \nExplain apoplastic and symplastic pathways of water movement in roots.
                                \nAnswer:
                                \nPlants absorb water by the root hairs in two distinct pathways namely, the apoplast pathway, and symplast pathway.<\/p>\n

                                In the apoplast pathway, the movement of water occurs exclusively through the intercellular spaces and the walls of the cells. This can take place only up to the endodermis because the suberised Casparian strip will block the further movement of water.<\/p>\n

                                In the symplast pathway, the movement of water takes place through the interconnected protoplasts through cytoplasm and plasmodesmata connections. This is the most accepted pathway.<\/p>\n

                                Structure of not hair:
                                \nRoot hairs are unicellular and arise from some of the epiblema cells. These cells enclose a large vacuole surrounded by thin cytoplasm which extends into root hair. There is a single nucleus in the cytoplasm at the tip of the root hair. The root hair is covered by a thin, and permeable cell wall made up of cellulose and Pectin.<\/p>\n

                                  \n
                                • The total amount of water present in the soil is called hoard.<\/li>\n
                                • The water available to the plants for absorption is called Chard.<\/li>\n
                                • Soil water that can not be absorbed by the plait is Echard.<\/li>\n
                                • The path of absorption of water \u00a1n roots is as follows:<\/li>\n<\/ul>\n

                                  Root hairs \u2192 Epiblema \u2192 Cortex \u2192 Endodermis (Passage cells) \u2192 Pericycle \u2192 Xylem
                                  \n\"1st
                                  \nPathway of water movement in the root<\/p>\n

                                  Question 32.
                                  \nDraw a neat labeled diagram of a neuron.
                                  \nAnswer:
                                  \n\"1st<\/p>\n

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

                                  II. Answer any THREE of the following questions in 200-250 words each, wherever applicable. (5 \u00d7 3 = 15)<\/span><\/p>\n

                                  Question 33.
                                  \nDiscuss the uses of algae.
                                  \nAnswer:<\/p>\n

                                    \n
                                  1. Brown algae like sargassum, laminaria, ficus are good sources of agar. It is used in the preparation of nutrient agar, a microbial growth medium.<\/li>\n
                                  2. Algin extracted from brown algae is used in the preparation of Ice creams, jellies, and chocolates.<\/li>\n
                                  3. Some algae like Ulva, Dictyota, and sargassum are used as food, as they are rich in mineral ions.<\/li>\n
                                  4. Algae are used as fodder.<\/li>\n
                                  5. Some algae are used as biofertilizers.<\/li>\n<\/ol>\n

                                    Question 34.
                                    \nEnumerate salient characters of class Mammalia.
                                    \nAnswer:
                                    \nClass Mammalia:<\/p>\n

                                      \n
                                    1. Class Mammalia includes warm-blooded and highly organized animals possessing mammary (milk) glands for suckling their young ones. They live almost in all the environments of the world and undergo secondary adaptation to suit their habitats. They are also known as hair quadrupeds.<\/li>\n
                                    2. Mammals are all homoeothermic (warm-blooded) animals.<\/li>\n
                                    3. The body shape varies, and it is covered by hairs.<\/li>\n
                                    4. The body is divisible into the head, neck, trunk, and tail.<\/li>\n
                                    5. Skin is glandular and includes sebaceous, and sweat glands in both the sexes, mammary glands in the females.<\/li>\n
                                    6. The Head region possesses a pair of eyes protected by eyelids and eyelashes, a pair of external ears or pinnae, and a pair of external nares.<\/li>\n
                                    7. They possess two pairs of pentadactyl legs, which are variously modified to perform different functions [like walking, running, climbing, swimming, burrowing, and flying]. Digits bear horny claws, nails, or hoofs.<\/li>\n
                                    8. Teeth are placed in sockets [Thecodont]. Teeth are heterodont [different types of teeth i.e, all are not of the same morphology], and diphyodont [i.e, 2 sets of teeth milk teeth, and permanent teeth].<\/li>\n
                                    9. There is well-developed voice apparatus, the larynx.<\/li>\n
                                    10. There is a muscular diaphragm separating the thorax and abdomen.<\/li>\n
                                    11. Respiration is by lungs.<\/li>\n<\/ol>\n

                                      \"KSEEB<\/p>\n

                                      Question 35.
                                      \nExplain the structure of mitochondria with a neat labeled diagram.
                                      \nAnswer:
                                      \n\"1st
                                      \nSection through mitochondrion (diagrammatic)
                                      \nThe elementary particles have been shown only on one crista.<\/p>\n

                                      It is present in eukaryotes except for mammalian RBC, and absent in prokaryotes. Its shape is oval, or sausage. Its number per cell depends on the metabolic state of the cell.<\/p>\n

                                      Structure: The mitochondria are bounded by two lipoprotein unit membranes namely the outer membrane and inner membrane. In between, they lie per mitochondrial matrix containing water, minerals, and enzymes.<\/p>\n

                                      The outer membrane is smooth and unfolded while the inner membrane is folded and it produces an inward finger-like process called Castle. Along the inner surface of the inner membrane, there are numerous tiny tadpole-like structures called elementary particles or F particles, Racker\u2019s particles, or exosomes. F1 particle contains basal piece. stalk and head. Sites of ATPase are between adjacent elementary particles.<\/p>\n

                                      The inner membrane contains an electron transport system. it is made up of a chain of co-enzymes in the order of NAD, FAD, cytochrome B, cyt C, cyt A, cyt A3. The inner space of mitochondria is filled with a dense fluid called mitochondria matrix containing water, proteins, lipids, all enzymes of Kreb\u2019s cycle, circular DNA, and 80s ribosomes.<\/p>\n

                                      Functions:<\/p>\n

                                        \n
                                      1. Mitochondria are the centers of aerobic respiration.<\/li>\n
                                      2. They are the sites of synthesis and storage of energy as ATP. Hence called the powerhouse of the cell.<\/li>\n
                                      3. As they have circular DNA & ribosomes, they synthesize a few proteins for their own requirement. Hence they are called \u2018Semi-autonomous cell organelles\u2019.<\/li>\n<\/ol>\n

                                        Question 36.
                                        \nDescribe the various stages of the I prophase of I meiosis.
                                        \nAnswer:
                                        \nProphase I: It lasts for quite a long period and is studied under five substages.<\/p>\n

                                          \n
                                        1. Leptotene<\/li>\n
                                        2. Zygotene<\/li>\n
                                        3. Pachytene<\/li>\n
                                        4. Diplotene<\/li>\n
                                        5. Diakinesis.<\/li>\n<\/ol>\n

                                          1. Leptotene: (Gr leptons slender; one – thread)
                                          \nThe chromosomes are thin, long, and uncoiled. Each is a double chromosome consisting of two chromatids. These chromatids are held firmly.
                                          \nEach chromosome appears as a string of beads, the beads are the chromomeres.<\/p>\n

                                          2. Zygotene: (Gr: Zygon-inale; tene- thread)
                                          \nDuring this stage, the pairing of homologous chromosomes (half of the maternal and half of them paternal). This pairing is called synapsis. The pairs so formed are called bivalents.<\/p>\n

                                          Each bivalent consists of four chromatids and is therefore called a tetrad. The two chromatids of the same chromosomes are called sister chromatids and the belonging to two different chromosomes of a homologous pair are termed non-sister chromatids.<\/p>\n

                                          3. Pachytene: (Gr: Pachus – thick tene – thread) .
                                          \nCrossing over takes place by breakage and reunion of chromatid segments. After crossing over, the two chromatids of a chromosome become dissimilar.<\/p>\n

                                          The points of interchange are X-shaped and are called chiasmata. (sing chiasma)<\/p>\n

                                          4. Diplotene: (Gr: Diplo – double; tene – thread)<\/p>\n

                                            \n
                                          • Repulsion between homologous chromosomes begins.<\/li>\n
                                          • Each tetrad now appears in different shapes i.e, X-shaped, \u20188\u2019 shaped, or \u2018O\u2019 shaped.<\/li>\n
                                          • Repulsion results in the criminalization of chiasmata (sliding of chiasmata towards the ends of chromosomes.<\/li>\n<\/ul>\n

                                            5. Diakinesis: (Gr: dia-cross; kinesis- movement).<\/p>\n

                                              \n
                                            • The nucleolus breaks down and disappears.<\/li>\n
                                            • Spindle fibers appear.<\/li>\n
                                            • The nuclear membrane breaks down.<\/li>\n
                                            • Chromosomes are released into the cytoplasm.<\/li>\n<\/ul>\n

                                              \"KSEEB<\/p>\n

                                              Question 37.
                                              \nDiscuss the role of pancreatic hormones in the regulation of blood glucose levels.
                                              \nAnswer:
                                              \nPancreas:
                                              \nThe pancreas is both an exocrine and an endocrine gland. For its endocrine function, it has islets of Langerhans. These islets have \u03b2 (beta) or B cells, \u03b1 (alpha) or A cells, and (delta) or D cells. The B cells secrete insulin and A cells secrete glucagon. Both are proteinaceous hormones regulating blood glucose levels.<\/p>\n

                                              The D cells secrete a hormone called somatostatin. It inhibits the digestion and absorption of nutrients. It also inhibits the secretion of insulin and glucagon.<\/p>\n

                                              1. Glucagon:<\/p>\n

                                                \n
                                              • It is a peptide hormone.<\/li>\n
                                              • It is a hyperglycemic hormone, i.e., it increases the level of glucose.<\/li>\n
                                              • It acts on the liver cells and hepatocytes in the blood.<\/li>\n
                                              • It stimulates glycogenolysis and increases the level of glucose in the blood.<\/li>\n
                                              • It stimulates gluconeogenesis and the synthesis of glucose from amino acids.<\/li>\n<\/ul>\n

                                                2. Insulin:<\/p>\n

                                                  \n
                                                • It is a peptide hormone.<\/li>\n
                                                • It is a hypoglycemic hormone, i.e., it reduces the level of glucose in the blood by stimulating the uptake and utilisation of glucose by tissue cells.<\/li>\n
                                                • It acts on the hepatocytes and stimulates the conversion of glucose into fats.<\/li>\n
                                                • It also acts on adipocytes and stimulates the conversion of glucose into fats.<\/li>\n
                                                • Deficiency of insulin causes hyperglycemia and prolonged hyperglycemia results in diabetes mellitus<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

                                                  Students can Download 1st PUC Biology Previous Year Question Paper March 2014 (South), Karnataka 1st PUC Biology Model Question Papers with Answers helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations. Karnataka 1st PUC Biology Previous Year Question Paper March 2014 (South) Time: 3.15 Hours Max Marks: …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/90127"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=90127"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/90127\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=90127"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=90127"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=90127"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}