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Samacheer Kalvi Class 11 Botany Practice Question Papers

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Brain Grain · braingrain.in
Botany — Practice Paper · Set 1
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15

Choose the correct answer. (Answer all questions.)

1.Plants with incomplete flowers either a petalous or with undifferentiated calyx and corolla are placed under the sub class a) Heterornerae b) Monochlarnydeae c) Bicarpellatae d) Monocotyledonae[1]
2.Which wood is also known as Non-porous a) Softwood b) Heartwood c) Hardwood d) Sapwood[1]
3.Phytochrome is a) Reddish phytohormone b) Bluish biliprotein pigment c) Photoreceptor of apical bud d) Unstable pigment molecule[1]
4.Both viruses and bacteria contain a. Plasma membrane b. Protein wat c. Peptidoglycan d. Nucleic acids[1]
5.Mad cow disease is caused by …………….(a) viroids(b) virusoids(c) prions(d) viruses[1]
6.The organelle made up of nine triplet peripheral fibrils are known as a) Microbodies b) Tululin c) Centrosome d) Centroles[1]
7.What type of transpiration is possible in the xerophyte Opuntia?(a) Stomatal(b) Lenticular(c) Cuticular(d) All the above[1]
8.Stomata of a plant open due to a) Influx of K + b) Effrilx of K + c) Influx of Cl – d) Influx of OH –[1]
9.Which of the following plant material is an efficient water imbibant? a) Lignin b) Pectin c) Cellulose d) Agar[1]
10.Which of the following process is called reverse of Glycolysis? a) CO 2 reduction b) RUBP carboxylation c) RUBP regeneration d) ATP synthesis[1]
11.Which of the following represent gametophytic generation in Pteridophytes? a. Prothallus b. Thallus c. Cone d. Rhizophore[1]
12.(i) Library of British Museum – A. Revision (ii) Malvaceae of India by T.K. Paul – B. Catalogue (iii) Family of Lentibulariaceae by M.K. Janarthanam & Henry – C. Botanical Garden Lucknow (iv) 500 species of rose hybrids – D. Monograph[1]
13.Which chlorophyll molecule does not have a phytol tail? a) Chl – a b) Chl – b c) Chl – c d) Chl – d[1]
14.Parvo viruses have …………….(a) ssDNA(b) dsDNA(c) ssRNA(d) dsRNA[1]
15.Most of the neurons in the brain are in …………… stage.(a) G 1(b) S(c) G 2(d) G 0[1]
Part II — Short Answer Questions 14 × 2 = 28

Answer briefly. (Answer all questions.)

16.Commercial cork is obtained from a) Oak b) Silver oak c) Pine d) Ficus[2]
17.Find out the True and False statements from the following and on that basis find the correct answer: (i) Documents of all plant species in a given geographical area is known as – Monograph (ii) These are often descriptive & poetic references to plants – Vernacular name (iii) A complete global account of a taxon of any rank – Flora (iv) Tools of Identification implemented by Computer – Polyclave key[2]
18.The given diagram is spadix inflorescence[2]
19.When respiratory inhibitors like KCN, chloroform are applied: (a) there is a decrease in the rate of respiration and an increase in the rate of absorption of water. (b) there is an increase in the rate of respiration and a decrease in the rate of absorption of water. (c) there is a decrease in the rate of respiration and also a decrease in the rate of absorption of water. (d) there is an increase in the rate of respiration and also in the rate of absorption of water.[2]
20.Identify the diagram.[2]
21.Mention the internal factors, that affect the growth of plants.[2]
22.Define Growth.[2]
23.Why do you call Abscisic acid (ABA) as stress hormone?[2]
24.Find out the aquatic bryophytes of the following. a. Riella b. Ricciocarpus c. Riccia d. Bryopteris (i) a&c (ii) b&c (iii) c&d (iv) a&b[2]
25.Br, Ebrl, O7 p3+3 A(3) Go – is a. This F.D of male flower of musa b. The F.D of crotalaria juncea c. The F.D. of male flower of phyllanthus amaras d. The F.D of male flower of cocos nucifera[2]
26.Botanical Name Common Name (I) Glycirrhiza glabra A. Thanneer Muttan (II) Withania somnifera B. Athimaduram (III) Asperagus racemosus C. Senkandal (IV) Gloriosa superba D. Amukkara[2]
27.Identify true statement regarding light reaction of photosynthesis? (a) Splitting of water molecule is associate with PS I. (b) PS I and PS II involved in the formation of NDPH + H +. (c) The reaction center of PS I is Chlorophyll a with absorption peak at 680 nm. (d) The reaction center of PS II is Chlorophyll a with absorption peak at 700 nm.[2]
28.I) Phloem fibres and phloem parenchyma, are absence in primary phloem of monocot stem. II) Phloem fibres are also known as Libriform fibres. Ill Sieve cells are main food conducting elements of Angiosperms IV) Phloem fibres are absent in primary phloem of Dicot stem[2]
29.Removal of a ring of wood tissue outside the vascular cambium from the tree trunk kills it because a) Water cannot move up b) Food does not travel down and root become starved c) Shoot apex become starved d) Annual rings are not produced[2]
Part III — Long Answer Questions 10 × 5 = 50

Answer in detail. (Answer all questions.)

30.Give an account of botanical description of Allium cepa.[5]
31.What are the practical applications of Vernalization?[5]
32.Differentiate floating respiration and protoplasmic respiration.[5]
33.What is meant by kranz Anatomy? What is its importance.[5]
34.What are the conditions for the occurrence of Non-cyclic photophosphorylation?[5]
35.A timer merchant bought 2 logs of wood from, a forest & named them A & B, The log A was 50 year old & B was 20 years old. Which log of wood will last longer for the merchant? Why?[5]
36.Write the Industrial uses of alcoholic fermentation.[5]
37.How will you calculate net products of one sucrose molecule upon complete oxidation during aerobic respiration as per recent view?[5]
38.How phosphorylase enzyme open the stomata in starch sugar interconversion theory?[5]
39.Write an essay on the role of ethylene on plant physiology and agriculture.[5]
🔑 Show Answer Key — Set 1
  1. 1. b) Monochlamvdeae
  2. 2. a. Softwood
  3. 3. b) Bluish biliprotein pigment
  4. 4. d. Nucleic acids
  5. 5. (c) prions
  6. 6. d) Centroles
  7. 7. (b) Lenticular
  8. 8. a) Influx of K +
  9. 9. d. Agar
  10. 10. a) CO 2 reduction
  11. 11. a. Prothallus
  12. 12. a) B A D C
  13. 13. (c) Chl – c
  14. 14. (a) ssDNA
  15. 15. (d) G 0
  16. 16. The correct answer is a) Oak. Commercial cork is obtained from the bark of the oak tree, specifically from Quercus suber, commonly known as the cork oak. The cork tissue, which is the outer protective layer of the bark produced by the phellogen, is harvested from these trees and used commercially for various purposes including bottle stoppers, insulation materials, and other products. The other options like silver oak, pine, and Ficus do not yield commercially viable cork.
  17. 17. Let's evaluate each statement for its truthfulness. (i) Documents of all plant species in a given geographical area is known as – Monograph. This statement is False. A document of all plant species in a given geographical area is known as a Flora, not a Monograph. A Monograph provides a comprehensive global account of a single taxon (e.g., a genus or family). (ii) These are often descriptive & poetic references to plants – Vernacular name. This statement is True. Vernacular names, or common names, are often locally specific, descriptive, and can sometimes have poetic or cultural significance. (iii) A complete global account of a taxon of any rank – Flora. This statement is False. As mentioned, a Flora covers a geographical area. A complete global account of a taxon of any rank is a Monograph. (iv) Tools of Identification implemented by Computer – Polyclave key. This statement is True. Polyclave keys, also known as multi-access keys, are identification tools that allow users to select multiple characters in any order, often implemented through computer programs or digital platforms, making identification more flexible and efficient. Therefore, the correct sequence of True and False statements is False, True, False, True, which corresponds to option b).
  18. 18. The given diagram illustrates a spadix inflorescence. In this type of inflorescence, the A represents the central axis, which is typically thick, fleshy, and unbranched. The B indicates the female flowers, which are usually located towards the base of the spadix. The C points to the male flowers, which are generally situated above the female flowers on the central axis. This arrangement is characteristic of plants like Araceae family members, where the spadix is often enclosed by a large, leaf-like bract called a spathe.
  19. 19. (c) there is a decrease in the rate of respiration and also a decrease in the rate of absorption of water. Respiratory inhibitors such as potassium cyanide and chloroform block the electron transport chain and inhibit aerobic respiration, leading to a significant decrease in the production of ATP. Since the absorption of water and mineral ions by root cells is an active transport process that requires energy in the form of ATP, the inhibition of respiration results in decreased availability of ATP. This causes a corresponding decrease in the rate of water absorption by the roots. Therefore, when respiratory inhibitors are applied, both respiration and water absorption rates decrease simultaneously.
  20. 20. The diagram illustrates root nodules of a leguminous plant. These are specialized structures formed on the roots of legumes as a result of a symbiotic interaction with nitrogen-fixing bacteria, predominantly Rhizobium species. When Rhizobium bacteria infect the root hairs, they induce the formation of these nodules. Inside the nodules, the bacteria differentiate into bacteroids and fix atmospheric nitrogen into ammonia, which is then assimilated by the plant. This process is crucial for the plant's nitrogen supply, especially in nitrogen-deficient soils. The plant, in turn, provides the bacteria with carbohydrates and a low-oxygen environment, maintained by a pigment called leghemoglobin, which is essential for the nitrogenase enzyme's activity.
  21. 21. Genes are intracellular factors for growth. Phytohormones are intracellular factors for growth, eg: auxin, gibberellin, cytokinin. C/N ratio.
  22. 22. Growth is an intrinsic property of all living organisms through which they increase in cell number and cell mass. It is an irreversible increase in size and dry weight of an organism resulting from the synthesis of new protoplasm and accumulation of biomass. Growth involves cell division and cell elongation, leading to an increase in the overall dimensions and complexity of the organism.
  23. 23. Abscisic acid (ABA) is called a stress hormone because it plays a crucial role in protecting plants from water stress and other environmental stresses. When plants experience water stress or drought conditions, ABA levels increase, which inhibits shoot growth and promotes the growth of the root system. By reducing shoot growth, ABA minimizes water loss through transpiration, while promoting root growth helps the plant access water from deeper soil layers. This redistribution of growth resources allows the plant to survive under water-limited conditions. Additionally, ABA regulates stomatal closure, reducing water loss and helping the plant cope with drought stress. These protective mechanisms make ABA essential for plant survival under adverse environmental conditions, justifying its designation as a stress hormone.
  24. 24. (iv) a&b
  25. 25. The floral diagram (F.D.) represented by Br, Ebrl, O7 p3+3 A(3) Go is the F.D. of the male flower of Phyllanthus amarus. This formula indicates the presence of bracts (Br) and bracteoles (Ebrl). The perianth (P) consists of two whorls of three tepals each (3+3), which are free. The androecium (A) has three stamens, which are free (3). The gynoecium (G) is superior (o) and has three carpels, which are fused (3), but in a male flower, the gynoecium is represented as rudimentary or absent, hence the 'o' indicating a superior ovary that is non-functional or absent in male flowers.
  26. 26. The correct matching of Botanical Name to Common Name is as follows: (I) Glycirrhiza glabra is commonly known as Athimaduram (B). (II) Withania somnifera is commonly known as Amukkara (D). (III) Asperagus racemosus is commonly known as Thanneer Muttan (A). (IV) Gloriosa superba is commonly known as Senkandal (C). Therefore, the correct sequence is B D A C. Glycirrhiza glabra is widely recognized as licorice, and Athimaduram is its common name in many Indian languages, valued for its medicinal properties. Withania somnifera, or Ashwagandha, is also known as Amukkara. Asparagus racemosus is commonly called Shatavari or Thanneer Muttan, and Gloriosa superba is a striking flowering plant often referred to as Glory Lily or Senkandal.
  27. 27. (b) PS I and PS II are both involved in the formation of NADPH + H+. Photosystem II (PS II) is responsible for the initial excitation of electrons and the splitting of water molecules (photolysis), releasing electrons, protons, and oxygen. These electrons are then passed through an electron transport chain. Photosystem I (PS I) receives electrons from this chain and further excites them using light energy. The energized electrons from PS I are then transferred to ferredoxin, which ultimately reduces NADP+ to NADPH + H+ with the help of the enzyme NADP+ reductase. Therefore, both photosystems are integral to the non-cyclic electron flow that culminates in the production of NADPH + H+, a crucial reducing agent for the Calvin cycle.
  28. 28. a) True – False – True – True. Phloem fibres and phloem parenchyma are indeed absent in the primary phloem of monocot stems. Phloem fibres are also known as libriform fibres, making the second statement false. Sieve cells are the main food-conducting elements in gymnosperms, while sieve tube elements are the main conducting elements in angiosperms, making the third statement false. Phloem fibres are absent in the primary phloem of dicot stems, which is true.
  29. 29. The correct answer is b) Food does not travel down and root become starved. When a ring of wood tissue outside the vascular cambium is removed from the tree trunk, this process is called girdling or ringing. The removal of this tissue destroys the phloem, which is the tissue responsible for the translocation of food (photosynthates) from the leaves downward to the roots and other non-photosynthetic parts. Without this downward movement of food, the roots become starved of nutrients and eventually die, leading to the death of the entire tree. Water movement through the xylem is not directly affected by this removal, and the shoot apex may initially survive, but the root starvation is the primary cause of death.
  30. 30. Habit – Perrennial herb with bulb Root – Fibrous adventitious root system Stem – Underground bulb Leaf – Radical leaves cylindrical fleshy with sheathing leaf bases & parallel venation Inflorescence – scafrigerous, pedicels of equal length arising from apex of peduncle Flower – Small white Actinomorphic, Bracteate, eBracteolate Bisexual Complete Monochiamydeous. Trimerous – hypogynous Flowers – Protandrous Perianth – 6 Tetals in 2 whorls of 3 each syntepalous Valvate acstivatíon Androecium – 6 stamens in a whorls of 3 each epipelatous apostamenous Anther – Dithecous basifixed, introse and longitudinal dehiscence Gynoecium Ovary – Superior, tricarpellary trilocular 2 ovules in each locule on axile placentation Style – simple, slender Sligma – simple Fruit – loculicidal capsule.
  31. 31. It shortens the vegetative period and induces the plant to flower earlier. It increases the cold resistance of the plants. It increases the resistance of plants to fungal disease. Plant breeding can be accelerated.
  32. 32. Floating respiration and protoplasmic respiration differ in their respiratory substrates and products. In floating respiration, carbohydrates, fats, or organic acids serve as the respiratory substrate, and these are oxidized to produce energy in the form of ATP without generating toxic byproducts. This is the common mode of respiration in most plant and animal cells and does not produce any harmful substances. In contrast, protoplasmic respiration uses proteins as the respiratory substrate, which is a rare mode of respiration that occurs under specific conditions such as starvation or stress. When proteins are used as respiratory substrates, the deamination process liberates toxic ammonia as a byproduct, which must be either converted to less toxic compounds like urea or excreted from the organism. This fundamental difference in substrate utilization and product formation makes protoplasmic respiration an emergency metabolic pathway used only when carbohydrates and fats are depleted.
  33. 33. Kranz anatomy is a specialized leaf anatomy characteristic of C4 plants, such as maize, sugarcane, and sorghum, which enables them to efficiently fix carbon dioxide at low concentrations and high temperatures. The term 'Kranz' is German for 'wreath' or 'halo,' referring to the distinctive arrangement of cells around the vascular bundles. In plants exhibiting Kranz anatomy, the vascular bundles are surrounded by two concentric rings of cells. The inner ring consists of large, thick-walled bundle sheath cells that are rich in chloroplasts and often contain starch grains. These bundle sheath cells are typically large and have few, if any, intercellular spaces. The outer ring is composed of mesophyll cells, which are also chloroplast-rich but are arranged more loosely and have smaller chloroplasts compared to the bundle sheath cells. This anatomical uniqueness, where the bundle sheath cells have large chloroplasts while the surrounding spongy mesophyll tissue has fewer or smaller chloroplasts, is crucial for the C4 pathway. The bundle sheath chloroplasts often lack grana (agranal chloroplasts) or have reduced grana, and they are the site of the Calvin cycle, while the mesophyll cells are where the initial CO2 fixation occurs. This spatial separation of photosynthetic processes in Kranz anatomy helps to concentrate CO2 around RuBisCO in the bundle sheath cells, minimizing photorespiration and enhancing the efficiency of CO2 fixation, especially in hot and dry environments, making C4 plants more productive than C3 plants under such conditions.
  34. 34. Non-Cyclic Photo Phosphorylation occurs, when. There is the availability of NADP + for reduction. Two molecules of water go back to the so. When there is the splitting of water molecules. When both PSI and PS II are activated.
  35. 35. In wood, the older it is, the stronger it becomes. Log A – Which was 50 years old is stronger and it will last longer. In a tree the central part of the wood will be darker in colour, dead in nature known as Heartwood or Duramen, and the outer sad wood is lighter in colour, living and conducting water. In the central Heartwood the conduction is blocked by the formation of tyloses from the nearby parenchyma cells, and dead. In the fully developed tyloses, starch crystals, resins, gums, oils tannins and coloured substances are found and it becomes very hard and durable. It is more resistant to the attack of microbes and insects like termites. Older woods have more heartwood than sapwood. Here log ‘A’ is older, has more heartwood and it is stronger and will last longer.
  36. 36. In bakeries, it is used for preparing bread, cakes, biscuits. In beverage industries for preparing wine and alcoholic drinks. In producing vinegar and in tanning, curing of leather. Ethanol is used to make gasohol (a fuel that is used for cars in Brazil).
  37. 37. When the cost of transport of ATPs from the matrix into the cytosol is considered, the number will be 2.5 ATPs for each NADH + H + and 1.5 ATPs for each FADH 2 oxidized during the electron transport system. Therefore, in plant cells net yield of 30 ATP molecules for complete aerobic oxidation of one molecule of glucose. But in those animal cells (showing malate shuttle mechanism) net yield will be 32 ATP molecules. Since the sucrose molecule gives, two molecules of glucose and net ATP in plant cell will be 30 × 2 = 60. In an animal cell, it will be 32 × 2 = 64. Part-II. 11th Bio Botany Guide Respiration Additional Important Questions and Answers I. Choose The Correct Answer
  38. 38. The discovery of the enzyme phosphorylase in guard cells by Hanes in 1940 provided strong support for the starch-sugar interconversion theory regarding stomatal movement. This theory explains how the interconversion of starch and sugar, influenced by pH changes, leads to the opening and closing of stomata. During the day, photosynthesis occurs in the guard cells, consuming carbon dioxide and leading to an increase in the pH of the guard cell sap. This higher pH activates the enzyme phosphorylase, which then hydrolyses starch into sugar (specifically glucose-1-phosphate, which is then converted to glucose and then sucrose). The accumulation of sugars increases the solute concentration inside the guard cells, lowering their water potential. Consequently, water moves from the adjacent subsidiary cells into the guard cells by osmosis, causing the guard cells to become turgid and bow outwards, leading to the opening of the stomata. Conversely, during the night, photosynthesis ceases, and carbon dioxide accumulates due to respiration, leading to a decrease in the pH of the guard cell sap. This lowered pH inactivates phosphorylase and activates another enzyme, leading to the conversion of sugar back into starch. The decrease in sugar concentration raises the water potential inside the guard cells, causing water to move out of the guard cells and back into the subsidiary cells. As a result, the guard cells become flaccid and collapse, leading to the closure of the stomata.
  39. 39. Almost all plant tissues produce ethylene gas in minute quantities. 1. Discovery: In 1924, Denny found that ethylene stimulates the ripening of lemons. In 1934, R. Gane found that ripe bananas contain abundant ethylene. In 1935, Cocken et al., identified ethylene as a natural plant hormone. 2. Occurrence: Maximum synthesis occurs during climacteric ripening of fruits and tissues undergoing senescence. It is formed in almost all plant parts like roots, leaves, flowers, fruits and seeds. 3. Transport in plants: Ethylene can easily diffuse inside the plant through intercellular spaces. 4. Precursor: It is a derivative of amino acid methionine, linolenic acid and fumaric acid. 5. Bioassay (Gas Chromatography): Ethylene can be measured by gas chromatography. This technique helps in the detection of exact amount of ethylene from different plant tissues like lemon and orange. 6. Physiological Effects: * Ethylene stimulates respiration and ripening in fruits. * It stimulates radial growth in sterft and roof and inhibits linear growth. * It breaks the dormancy of buds, seeds and storage organs. * It stimulates the formation of an abscission zone in leaves, flowers and fruits. This makes the leaves to shed prematurely. * Inhibition of stem elongation (shortening the internode). * In low concentration, ethylene helps in root initiation. * Growth of lateral roots and root hairs. This increases the absorption surface of the plant roots. * The growth of fruits is stimulated by ethylene in some plants. It is more marked in climacteric fruits. * Ethylene causes epinasty. 7. Agricultural role: * Ethylene normally reduces flowering in plants except in Pineapple and Mango. * It increases the number of female flowers and decreases the number of male flowers. * Ethylene spray in cucumber crops produces female flowers and increases the yield.
Brain Grain · braingrain.in
Botany — Practice Paper · Set 2
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15

Choose the correct answer. (Answer all questions.)

1.Photosynthesis is the major:(a) endothermic reaction(b) exothermic reaction(c) endergonic reaction(d) exergonic reaction[1]
2.(i) When the small pieces of golgibody pinches off from its tubules to form – A. Chioroplast (ii) Fernandez moran particles occur in – B. Golgi apparatus (iii) Zymogen granules occur in – C. Lysosome (iv) Quantosomes are present in – D. Mitochondria[1]
3.The open form of the growth occurs in:(a) leaves and flowers(b) stem and root(c) leaves and stem(d) stem and flowers[1]
4.Which one of the following is a correct statement regarding Bryophyta a. Mostly terrestrial plants so water is not essential for reproduction b. The gametophyte is dominant but the sporophyte is independent c. They have well-developed xylem and phloem tissues d. They are the simplest land inhabiting cryptogams lacking vascular tissues.[1]
5.Which series includes epigynous flowers with an inferior ovary?(a) Heteromerae(b) Disaflorea(c) Inferae(d) Thalanifloreae[1]
6.The no of quanta of light required for the release of one oxygen molecule a) 18 quanta b) 8 quanta c) 81 quanta d) 19 quanta[1]
7.The most basic amino acid is a. Arginine b. Histidene c. Glycine d. Glutamine[1]
8.An example of feed back inhibition is a. cyanide action on cytochrome b. Sulpha drug on folic acid c. Allosteric inhibition of hexokinase by glucose- 6- phosphate d. The inhibition of succinic dehydrogenase by malonate[1]
9.Which of the following helps in the Ascent of sap? a) Root pressure b) Transpiration c) Capillarity d) All the above[1]
10.Which of the plant group has gametophyte as a dominant phase ? a. Pteridophytes b. Bryophytes c. Gymnosperm d. Angiosperm[1]
11.Cytokinins inducing cell division was first demonstrated by:(a) Haberlandt(b) Charles Darwin(c) Clarke(d) Hubert[1]
12.In mature sieve tubes, the pores in the sieve plates are blocked by a substance called a) gum & nesins b) Callose c) Callus d) Pectinose[1]
13.Which of the statement is not correct?(a) Meristematic cells are self-perpetuating(b) Meristematic cells are the most actively dividing cells(c) Meristematic cells have large vacuoles(d) Meristematic cells have dense cytoplasm with a prominent nucleus[1]
14.Look at the picture and find out the correct answer a. The Asexual reproduction in Ultrix by the formation of zoospores b. Akinetes formation in Pithophora c. Scalariform conjugation in Zygnema d. Zygospore formation in spirogyra[1]
15.The female sex organ of red algae is known as a. Archegonium b. Spermatogonium c. Carpogonium d. Oogonium[1]
Part II — Short Answer Questions 14 × 2 = 28

Answer briefly. (Answer all questions.)

16.Identify the diagram and Neatly label the parts[2]
17.Botanical Garden Major Attraction (i) Nation Botanical Garden Lucknow – Germplasm collection & exsitu conversation (ii) JNTBGRI Trivandrum (Kerala) – Bambusetum (iii) National orchidarium Yercaud – Fernery (iv) Indian Botanical Garden Kolkata – The great Banyan tree[2]
18.Why do we call Glucose and Fructose Isomers -Discuss.[2]
19.Identify the correctly matched pair a. Actinomycete – a) Late blight b. Mycoplasma – b) lumpy jaw c. Bacteria – c) crown gall d. Fungi – d) sandal spike[2]
20.Give examples for Nitrogen Fixation with out nodulation.[2]
21.Name 3 Dermatophytes[2]
22.Gemmae formation is not traced in which three of the given four options a. Marchanlia b. Riella c. Ricciocarpus d. Anthoceros (i) ab & c (ii) be & d (iii) ab & d (iv) ac & d[2]
23.Identify the diagram & Label the parts.[2]
24.Find out the Correct Statements the given below. a) Scientific Names are treated as Latin regardless of their derivation b) Cryptogams include non-flowering plants c) Linnaeus system of classification is known as the Natural system of classification d) According to APG IV Monocots contain 10 orders and 37 families (I) a & b (II) b & c (III) c & d (IV) a & d[2]
25.Differentiate between Anaphase I & Anaphase II of Meiosis.[2]
26.Write the missing A and B.[2]
27.Define Aeroponics.[2]
28.I) Prickles are one type of epidermal emergences with vascular supply II) Albuniinous cells! straburger cells – in conifers are analogous to companian cells of Angiosperm but III) Piliferous layer, Epiblema are other names of Endodermis. IV) Hypodermis of Dicot stem is living, whereas the Hypodermis of Moncot stem is dead.[2]
29.The given diagram is verticillaster[2]
Part III — Long Answer Questions 10 × 5 = 50

Answer in detail. (Answer all questions.)

30.Give the historial significance of Agent Orange[5]
31.Give an account of dry indehiscent fruits.[5]
32.Compare and contrast the photosynthetic processes in C 3 and C 4 plants.[5]
33.List out various types of Phyllotaxy.[5]
34.How the leaf hooks helps the Bignonia plant?[5]
35.Draw the different types of phloem elements and add a note on sieve tubes.[5]
36.Compare between Absolute and Relative growth rates[5]
37.Given an account of the Go phase.[5]
38.The pulp of pear is stony & gritty, whereas the seed coat of Pisum sativum seed coat is bony & shiny give reasons.[5]
39.Nitrogen fixation is shown by Prokaryotes and not by Eukaryotes comment.[5]
🔑 Show Answer Key — Set 2
  1. 1. (c) endergonic reaction
  2. 2. b) C D B A
  3. 3. (b) stem and root
  4. 4. The correct statement regarding Bryophyta is option d: They are the simplest land inhabiting cryptogams lacking vascular tissues. This statement accurately describes bryophytes as they represent the most primitive group of land plants that lack true vascular tissues such as xylem and phloem. Option a is incorrect because bryophytes are mostly terrestrial but water is absolutely essential for their reproduction, as male gametes require water to reach the female structures. Option b is incorrect because although the gametophyte is dominant in bryophytes, the sporophyte is not independent but rather dependent on the gametophyte for nutrition and support. Option c is incorrect because bryophytes lack well-developed xylem and phloem tissues, which is one of their defining characteristics.
  5. 5. (c) Inferae II. Fill up the blanks in the given Tabulation
  6. 6. b) 8 quanta
  7. 7. c. GIycine
  8. 8. c. Allosteric inhibition of hexokinase by glucose-6-phosphate
  9. 9. d. All the above
  10. 10. b. Bryophytes
  11. 11. (a) Haberlandt
  12. 12. b. Callose
  13. 13. (c) Meristematic cells have large vacuoles
  14. 14. c. Scalariform conjugation in zygoma. V.
  15. 15. c. Carpogonium
  16. 16. The given diagram illustrates the structure of a Hydathode, which is a specialized pore found on the epidermis of leaves, typically at the margins or tips, responsible for guttation. Guttation is the process of exudation of xylem sap from the intact margins of leaves. The labeled parts are A, which represents the Guard cell, although hydathodes are generally characterized by open pores without functional guard cells, sometimes modified epidermal cells are referred to in this context. B points to the Epithem, which is a mass of thin-walled parenchyma cells located beneath the hydathode pore. C indicates the Tracheids, which are the terminal xylem elements that supply water to the epithem cells.
  17. 17. The wrong answer is (iii) National Orchidarium Yercaud – Fernery. The National Orchidarium at Yercaud is known for its orchid collection, not a fernery. The other statements are correct: The National Botanical Garden at Lucknow is known for germplasm collection and ex-situ conservation, JNTBGRI at Trivandrum in Kerala features a Bambusetum, and the Indian Botanical Garden at Kolkata is famous for the Great Banyan tree.
  18. 18. Glucose and fructose are classified as isomers because they possess the same molecular formula, C6H12O6, but differ in their structural arrangements. Although both contain six carbon atoms, twelve hydrogen atoms, and six oxygen atoms, the atoms are arranged differently in space. Glucose is an aldohexose with an aldehyde group at the first carbon, forming a six-membered pyranose ring in its cyclic form. Fructose is a ketohexose with a ketone group at the second carbon, forming a five-membered furanose ring in its cyclic form. This difference in structure results in different chemical and biological properties despite their identical molecular formulas. Glucose serves as the primary energy source for cells and is the main product of photosynthesis, while fructose is sweeter than glucose and is commonly found in fruits and honey. These structural differences explain why the two sugars behave differently in metabolic pathways and have distinct physiological effects.
  19. 19. The correctly matched pair is: a. Actinomycete – lumpy jaw, b. Mycoplasma – sandal spike, c. Bacteria – crown gall, d. Fungi – late blight. Lumpy jaw is a disease of cattle caused by Actinomycetes. Sandal spike disease affecting sandalwood trees is caused by Mycoplasma. Crown gall, a plant disease characterized by tumor-like growths, is caused by the bacterium Agrobacterium tumefaciens. Late blight of potato is a fungal disease caused by Phytophthora infestans.
  20. 20. Nitrogen fixation without nodulation occurs in several plant-prokaryote associations where atmospheric nitrogen is converted to ammonia without the formation of specialized root nodules. In lichens, the photosynthetic partner is associated with cyanobacteria such as Anabaena and Nostoc, which fix atmospheric nitrogen. Anthoceros, a liverwort, forms a symbiotic relationship with the cyanobacterium Nostoc, allowing nitrogen fixation to occur within the plant tissues. Azolla, an aquatic fern, harbors the cyanobacterium Anabaena azollae in specialized leaf cavities, enabling nitrogen fixation without nodule formation. Cycas, a gymnosperm, maintains associations with cyanobacteria such as Anabaena and Nostoc in specialized structures called coralloid roots. These examples demonstrate that nitrogen fixation can occur through various symbiotic relationships without the formation of the typical root nodules seen in legume-Rhizobium associations.
  21. 21. Trichophyton Tinea Microsporum Epidermophyton are some fungi causing skin problems
  22. 22. The correct answer is (ii) be & d. Gemmae formation is not traced in Riella, Ricciocarpus, and Anthoceros. Gemmae are asexual reproductive structures found in certain bryophytes, particularly in liverworts like Marchantia, where they are produced in specialized cup-like structures called gemma cups. However, not all bryophytes produce gemmae. Riella and Ricciocarpus, which are also liverworts, do not form gemmae as a means of reproduction. Anthoceros, which is a hornwort, similarly does not produce gemmae. Therefore, among the four options given, gemmae formation is absent in Riella, Ricciocarpus, and Anthoceros.
  23. 23. The diagram illustrates the structure of Tyloses. A represents a Parenchyma cell, which is the origin of the tylosis. B points to the Tyloses themselves, which are balloon-like outgrowths from the parenchyma cells that protrude into the vessel lumen. C indicates the Vessel wall, the structural boundary of the water-conducting vessel. D denotes the Vessel Lumen, which is the central cavity of the vessel that becomes partially or completely blocked by the tyloses.
  24. 24. The correct statements are (a) Scientific Names are treated as Latin regardless of their derivation, and (b) Cryptogams include non-flowering plants. Therefore, option (I) a & b is the correct answer. Scientific names are indeed latinized to ensure universality and stability in nomenclature, making them understandable across different languages and regions. Cryptogams, such as algae, fungi, bryophytes, and pteridophytes, are characterized by their hidden reproductive organs and do not produce flowers or seeds, hence they are non-flowering plants. Linnaeus's system is primarily an artificial system, not a natural one, as it was based mainly on a few morphological characters, particularly sexual parts. The details regarding APG IV classification for monocots are specific and require precise verification, but statements (a) and (b) are fundamentally correct in botanical taxonomy.
  25. 25. Anaphase I and Anaphase II are two distinct stages of meiosis with important differences. During Anaphase I, homologous chromosomes separate and move toward opposite poles of the cell. Each chromosome still consists of two sister chromatids joined at the centromere, so the number of chromosomes moving to each pole is half the diploid number. This separation of homologous pairs is the key event that reduces the chromosome number. In contrast, during Anaphase II, sister chromatids separate at the centromere and move toward opposite poles. At this stage, the cell is already haploid, and the separation of sister chromatids produces individual chromosomes. Therefore, the fundamental difference is that Anaphase I involves the separation of homologous chromosomes while sister chromatids remain attached, whereas Anaphase II involves the separation of sister chromatids themselves.
  26. 26. A. Ribose is the five-carbon sugar found in RNA molecules, which is a key component of nucleotides. B. Adenine is one of the nitrogenous bases that pairs with thymine in DNA and uracil in RNA, serving as a fundamental building block of nucleic acids essential for storing and transmitting genetic information in cells.
  27. 27. Aeroponics is a soilless cultivation technique in which plant roots are suspended in air rather than being immersed in a growing medium. In this system, a nutrient solution is stored in a tank and is sprayed onto the suspended roots at regular intervals using a motor-driven rotor that creates a fine mist. This mist provides the roots with both essential nutrients and oxygen, allowing plants to absorb what they need while remaining in an air environment. The aeroponics system is highly efficient in water and nutrient use, as the mist is applied directly to the roots and excess solution drains back into the tank for recirculation. This technique is particularly useful for research purposes and commercial cultivation, and it allows for precise control over the nutrient environment and excellent aeration of the root system.
  28. 28. d) False – True – False – True. Prickles are epidermal emergences that lack vascular supply, unlike spines which are modified leaves with vascular tissue, making the first statement false. Albuminous cells (Strasburger cells) in conifers are indeed analogous to companion cells in angiosperms, making the second statement true. The piliferous layer and epiblema are other names for the root epidermis, not the endodermis, making the third statement false. The hypodermis of dicot stems is typically composed of living parenchyma or collenchyma, while in monocot stems it is often sclerenchymatous and dead, making the fourth statement true.
  29. 29. The given diagram represents a verticillaster inflorescence. In this type of inflorescence, the A denotes the central axis. The B points to the monochasial scorpioid lateral branches, which arise in the axils of opposite leaves and form dense clusters of flowers at each node. The C indicates the older flowers, which are typically located towards the base of these lateral branches, as the flowering proceeds acropetally within each cyme but appears whorled due to the condensed internodes. This type of inflorescence is characteristic of plants belonging to the Lamiaceae family, such as mint.
  30. 30. Mixture of two phenoxy herbicides – 2.4. D and 2.4.5 T together known as Agent orange. This Agent orange, was used by USA in Vietnam war as chemical warfare weapon to defoliate forests in Vietnam.
  31. 31. Dry indehiscent fruits are fruits that do not open or split to release their seeds at maturity. They have a hard, protective pericarp that remains intact. Achene is a monocarpellary superior ovary fruit from an apocarpous flower where the pericarp is free from the seed coat, found in Clematis and strawberry. Cypsela is a bicarpellary inferior ovary syncarpous fruit with reduced scales and hairy or feathery calyx lobes forming a pappus, found in Tridax and Helianthus. Caryopsis is a monocarpellary superior ovary fruit where the fruit wall is inseparably fused with the seed coat, found in Oryza and Triticum. Nut is a multicarpellary syncarpous superior ovary fruit with a hard, woody, or bony pericarp, found in Anacardium. Samara is a monocarpellary superior ovary fruit where the pericarp develops into a thin, wing-like structure that aids in wind dispersal, found in Pterocarpus. Utricle is a bicarpellary unilocular syncarpous superior ovary fruit where the pericarp loosely encloses the seed without being fused to it, found in Chenopodium. Each fruit type has specific characteristics related to the nature of the ovary and the development of the pericarp, which are important for plant identification and understanding seed dispersal mechanisms.
  32. 32. Contrast the photosynthetic processes in C 3 and C 4 plants: C 3 Plants: * CO 2 fixation takes place in mesophyll cells only. * CO 2 acceptor is RUBP only. * First product is 3C – PGA. * Kranz anatomy is not present. * Granum is present in mesophyll cells. * Normal Chloroplast. * Optimum temperature 20° to 25° C. * Fixation of CO 2 at 50 ppm. * Less efficient due to higher photorespiration. * RUBP carboxylase enzyme used for fixation. * 18 ATPs used to synthesize one glucose. * Efficient at low CO 2. * eg: Paddy, Wheat, Potato and so on. C 4 Plants: * CO 2 fixation takes place mesophyll and bundle sheath. * PEP in mesophyll and RUBP in bundle sheath cells. * First product is 4C – OAA. * Kranz anatomy is present. * Granum present in mesophyll cells and absent in bundle sheath. * Dimorphic chloroplast. * Optimum temperature 30° to 45° C. * Fixation of CO 2 even less than 10 ppm. * More efficient due to less photorespiration. * PEP carboxylase and RUBP carboxylase used. * 30 ATPs to produce one glucose. * Efficient at higher CO 2. * eg: Sugar cane, Maize, Sorghum, Amaranthus and so on.
  33. 33. Phyllotaxy refers to the arrangement of leaves on the stem. There are several distinct types of phyllotaxy observed in plants. In alternate spiral phyllotaxy, only one leaf is present at each node, and successive leaves are arranged in a spiral manner around the stem, as seen in Hibiscus. Alternate bifarous phyllotaxy shows leaves arranged in two rows that alternate with each other, exemplified by Polyalthia. Opposite superposed phyllotaxy has two leaves at each node positioned opposite to each other and in the same direction in successive nodes, as in Guava. Opposite decussate phyllotaxy displays one pair of leaves at each node positioned at right angles to the pair at the next lower node, characteristic of Calotropis. Ternate phyllotaxy involves three leaves attached at each node, as seen in Nerium. Whorled or verticillate phyllotaxy has more than three leaves arranged in a whorl at each node, exemplified by Allamanda. Additionally, leaf mosaic is a special arrangement where upper leaves have short petioles while lower leaves possess long petioles, allowing efficient light exposure, as observed in Acalypha. These various arrangements represent adaptations that maximize light exposure and reduce competition among leaves on the same plant.
  34. 34. In Bignonia unguiscati, commonly known as cat's claw or cat's nail, the terminal leaflets of the compound leaf undergo remarkable modification to form climbing organs. These terminal leaflets become transformed into three very sharp, stiff, and curved hooks that closely resemble the claws or nails of a cat. These specialized hooks serve a critical function in the plant's survival by clinging firmly to the bark of trees and other rough surfaces, thereby acting as efficient organs of support and attachment. This modification allows Bignonia to climb vertically on tree trunks and other structures without the need for twining or coiling movements. The hooks provide a secure grip that enables the plant to reach sunlight in the forest canopy while minimizing energy expenditure on stem thickening. This is an excellent example of how leaves can be modified from their typical photosynthetic function to serve specialized roles in plant support and climbing. Other examples of leaf modifications for climbing include phyllodes, which are winged leaf petioles or rachises that perform photosynthetic functions, as seen in Acacia auriculiformis and Nepenthes, where the petiole is modified to perform the function of a leaf.
  35. 35. Sieve tubes are long tubes formed by a series of cells known as sieve tube elements. Arranged one above another to form vertical sieve tube. No. of pores occur on end walls – known as sieve plate. Sieve plates may be simple or compound. Sieve elements show nacreous thickening on their lateral walls. Mature sieve tube, nucleus is absent, only lining layer of cyto plasm, a special phloem protein (slimy body) is seen in it. Mature sieve tubes pores blocked by a substance known as callose (callose plug) sieve tube function as food conducting tissue Angiosperm.
  36. 36. Absolute growth rate and relative growth rate are two different ways of measuring and expressing plant growth. Absolute growth rate refers to the total increase in growth of an organ or organism measured and compared per unit time, expressed in absolute units such as millimeters or grams per unit time. This measurement gives the actual amount of growth that has occurred. Relative growth rate, on the other hand, expresses the growth of a given system per unit time in relation to the initial size or parameter of that system. It is calculated by dividing the absolute growth by the initial size, resulting in a dimensionless ratio or percentage. Relative growth rate is particularly useful for comparing the growth rates of organisms or organs of different initial sizes, as it accounts for the starting size and provides a standardized measure of growth efficiency. While absolute growth rate indicates the actual amount of growth, relative growth rate indicates the rate of growth relative to the existing biomass.
  37. 37. The G0 phase, also known as the quiescent stage or G-zero phase, is a state that some cells enter after exiting the G1 phase of the cell cycle. Cells in G0 remain metabolically active and can perform their specialized functions, but they do not undergo proliferation or division. These cells can exist in the G0 phase for extended periods, sometimes for the entire lifespan of the organism. In the G0 phase, cells cease growth and exhibit a reduced rate of RNA and protein synthesis compared to actively dividing cells. However, the G0 phase is not necessarily permanent for all cell types. Some cells, such as mature neurons and skeletal muscle cells, remain permanently in G0 and do not re-enter the cell cycle under normal circumstances. In contrast, many other cells in animals can remain in G0 unless they receive appropriate growth factors or other extracellular signals that stimulate them to re-enter the G1 phase and resume proliferation. It is important to note that G0 cells are not dormant; they continue to carry out metabolic activities and maintain their cellular functions while remaining in a non-dividing state.
  38. 38. The pulp of pear is stony and gritty due to the presence of brachysclereids, which are short, isodiametric sclerenchyma cells distributed throughout the mesocarp tissue. These cells provide mechanical strength and create the characteristic hard, granular texture when the fruit is eaten. In contrast, the seed coat of Pisum sativum (garden pea) is bony and shiny because it contains osteosclereids, which are elongated, bone-like sclerenchyma cells that form a thick, protective layer. The osteosclereids are tightly packed and highly lignified, giving the seed coat its hard, smooth, and glossy appearance. Both types of sclerenchyma cells serve protective and supportive functions, but their different shapes, sizes, and arrangements result in the distinct textural and visual characteristics of these plant structures.
  39. 39. Nitrogen fixation is a biochemical process that is exclusively carried out by prokaryotes and not by eukaryotes, a distinction that reflects fundamental differences in their cellular machinery and enzymatic capabilities. The key reason for this limitation is that the enzyme nitrogenase, which is absolutely essential for reducing atmospheric nitrogen gas to ammonia, is present exclusively in prokaryotic organisms. Nitrogenase is a complex metalloenzyme that catalyzes the conversion of inert atmospheric nitrogen into ammonia, a form that can be utilized by living organisms. Eukaryotic organisms, including plants, fungi, and animals, lack the genetic information and cellular machinery necessary to synthesize and maintain functional nitrogenase enzymes. Prokaryotes that possess nitrogenase are called nitrogen fixers and include free-living bacteria such as Azotobacter and Clostridium, as well as symbiotic bacteria such as Rhizobium that live in association with leguminous plants. This prokaryotic monopoly on nitrogen fixation is one of the most important biochemical processes in the biosphere, as it makes atmospheric nitrogen available to all other organisms through the nitrogen cycle. The inability of eukaryotes to fix nitrogen is why they depend on prokaryotes and on the nitrogen cycle for their nitrogen nutrition.
Brain Grain · braingrain.in
Botany — Practice Paper · Set 3
Class: 11Samacheer KalviMax Marks: 93
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 15 × 1 = 15

Choose the correct answer. (Answer all questions.)

1.Bacteria that grow in high salinity condition is known as a. Methane bacterium b. Halobacterium c. Thermos aquaticus d. Agrobacterium[1]
2.The fruit is geocarpic in a) Vigna radiate b) Cablab purpuris c) Araehis hypogea d) Cicer arietinum[1]
3.The minerals placed under the list of unclassified minerals are a) Carbon. Hydrogen, & Oxygen b) Sodium. Silicon. Cobalt and selenium c) Copper, Iron, Cadmium, and selenium d) Magnesium, Sulphur, & Manganese[1]
4.The mineral required for the synthesis of IAA is a) Copper b) Magnesium c) Zinc d) Boron[1]
5.Father of Anatomy, as well as the scientist, who coined the term Meristem is a) Hofmeister b) Mettemius c) Nehemiah Grew d) Bloch[1]
6.The osmotic pressure of cell sap is maximum in a) Hydrophytes b) Halophytes c) Xerophytes d) Mesophytes[1]
7.Which one of the following is a wrong pair? a. Father of Indian Bryology- Prof. Shiv. Ram Kashyap b. Father of Indian Phycology – F.E. Fritsch c. The classification of gymnosperm – Sporn d. The father of Indian Paleobotany – Prof. Birbal Sahni[1]
8.Which one of the following is not a Ribovirus? a. Tobacco mosaic virus b. Cauliflower mosaic virus c. Human immune deficiency virus. d. Wound tumour virus d. Pilobolus[1]
9.Choose the natural Auxin of the following a) Anti Auxin b) NAA c) 2.4.D d) IndoleAcetic Acid (IAA)[1]
10.The general form of a plant is referred to as …………….(a) habitat(b) structure(c) habit(d) shape and size[1]
11.The ascent of sap is a) Upward movement of water in plants b) downward movement of water in plants c) upward and downward movement of water plants d) None of the above[1]
12.Identify the incorrect statement about the gram-positive bacteria. a. Teichoic acid absent b. A high percentage of peptidoglycan is found in the cell wall. c. Cell wall is single-layered d. Lipopolysaccharide is present in the cell wall.[1]
13.Vaccination for smallpox was discovered by …………….(a) W.M. Stanley(b) Adolf Mayer(c) Robert Koch(d) Edward Jenner[1]
14.Which of the element is involved in the synthesis of DNA and RNA:(a) calcium(b) magnesium(c) sulphuric(d) potassium[1]
15.a. Follicle – Calotropis b. Silicula – Capsella c. Loculicidal capsule – Lady’s finger d. Legume – Castor castor[1]
Part II — Short Answer Questions 14 × 2 = 28

Answer briefly. (Answer all questions.)

16.(i) Surface fibre – A. Jute (II) Soft fibre – B. Agave (III) Leaf fibre – C. Coconut (IV) Septate fibre – D. Cofton (V) Mesocarp fibre – E. Teak[2]
17.Mention the two Lateral meristems responsible for secondary growth.[2]
18.What are enzymes involved in phosphorylation and dephosphorylation reactions in EMP pathway?[2]
19.I) The bundle cap of Dicto stem is known as Hard bast. II) The bundle cap of Dicot stem is parenchymatous III) The bundle sheath of Dicot leaf is sclerenchymatous walls of Endodermis in Endodermis is known as the outermost layer of stele. IV) In Angiosperms pericycle gives rise to lateral roots[2]
20.Plant A in a nutrient medium shows whiptail disease plant B in a nutrient medium shows a little leaf disease. Identify mineral deficiency of plant A and B?[2]
21.What are the air pollutants, that affect the rate of photosynthesis?[2]
22.(i) Poly-B hydroxybutysate is a microbial plastic which is biodegradable (ii) Transfer of DNA from one bacterium to another is known as transduction (iii) Micrococcus must have oxygen to survive-known as an obligate aerobe (iv) Spirulina is rich in carbohydrates so treated as an alternative food.[2]
23.I) Sapwood – A. Softwood II) Heartwood – B. Hardwood III) Porous wood – C. Albumum IV) Nonporous wood – D. Duramen[2]
24.Name 4 common basidiomycetes[2]
25.Define cytoplasmic streaming.[2]
26.Why do some people have curly hair?[2]
27.I. Plasmid II. Heterocyst III. Glycocalyx IV. Mesosome[2]
28.Label the diagram parts correctly by choosing the right option. A B C D a Deoxyribose sugar Nitrogen base Nucleotide Phosphate b Deoxyribose sugar Phosphate Nucleotide Nitrogen base c Deoxyribose sugar Nitrogen base Nucleotide Phosphate d Deoxyribose sugar Phosphate Nitrogen base Nucleotide[2]
29.Why is it essential to do classification?[2]
Part III — Long Answer Questions 10 × 5 = 50

Answer in detail. (Answer all questions.)

30.Notes on photosystem and Reaction centre.[5]
31.Annual rings are not clear and distinct in desert trees and seashore plants – Justify.[5]
32.Give a general account of lichens[5]
33.Differentiate Haplontic and Diplontic life cycle.[5]
34.Name the 4 types of xylary fibres.[5]
35.Write down the characteristic features of DNA?[5]
36.What are the factors that affect senescence?[5]
37.What is Kranz Anatomy or what is meant by Dimorphism of Chloropiasts in C 4 plants.[5]
38.Differences between Diffuse porous wood and Ring porous wood[5]
39.Define the term diffusion.[5]
🔑 Show Answer Key — Set 3
  1. 1. b. Halobacterium
  2. 2. c) Arachis hypogea
  3. 3. b) Sodium, Silicon, Cobalt, and Selenium
  4. 4. c) Zinc
  5. 5. c. Nehemia Grew
  6. 6. b. Halophytes
  7. 7. Examining each pair: Prof. Shiv Ram Kashyap is indeed recognized as the Father of Indian Bryology, making option (a) correct. F.E. Fritsch is recognized as the Father of Indian Phycology, making option (b) correct. Sporn provided the classification of gymnosperms, making option (c) correct. Prof. Birbal Sahni is recognized as the Father of Indian Paleobotany, making option (d) correct. However, upon careful examination of the question asking for a wrong pair, option (b) stating that F.E. Fritsch was the Father of Indian Phycology is the wrong pair because while Fritsch was a prominent phycologist, he was not specifically Indian; the Father of Indian Phycology is more accurately attributed to another botanist. The answer is (b).
  8. 8. d. Wound tumour virus
  9. 9. d) Indole Acetic Acid (IAA)
  10. 10. (c) habit
  11. 11. a. upward movement of the water plants
  12. 12. a. Teichoic acid absent
  13. 13. (d) Edward Jenner
  14. 14. (b) magnesium
  15. 15. d. Legume
  16. 16. b) D – A – B – E. The correct matching is: Surface fibre (D) Cotton, Soft fibre (A) Jute, Leaf fibre (B) Agave, Septate fibre (E) Teak, and Mesocarp fibre (C) Coconut. Surface fibres are obtained from the surface of seeds, such as cotton. Soft fibres come from the stem of plants like jute. Leaf fibres are extracted from the leaves of plants such as agave. Septate fibres are found in wood and are characteristic of timber like teak. Mesocarp fibres are obtained from the middle layer of the fruit wall, as seen in coconut husk.
  17. 17. Secondary growth, which leads to an increase in the girth or diameter of the plant stem and root, is primarily brought about by the activity of two lateral meristems. These meristems are responsible for producing new cells that contribute to the secondary tissues. The two lateral meristems are the vascular cambium and the cork cambium. The vascular cambium is responsible for producing secondary xylem (wood) towards the inside and secondary phloem towards the outside, thus increasing the diameter of the vascular cylinder. The cork cambium, also known as phellogen, is responsible for forming the periderm, which includes the cork (phellem) and secondary cortex (phelloderm), replacing the epidermis as the protective outer layer of the plant in older stems and roots. This process is characteristic of dicotyledonous plants and gymnosperms.
  18. 18. In the Embden-Meyerhof-Parnas (EMP) pathway, phosphorylation and dephosphorylation reactions are catalyzed by specific enzymes. The enzymes involved in phosphorylation reactions are hexokinase, which phosphorylates glucose to glucose-6-phosphate, and phosphofructokinase, which catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate. These phosphorylation steps require energy input from ATP. The enzymes involved in dephosphorylation reactions are phosphoglycerate kinase, which catalyzes the transfer of a phosphate group from 1,3-bisphosphoglycerate to ADP, forming ATP, and pyruvate kinase, which catalyzes the transfer of a phosphate group from phosphoenolpyruvate to ADP, also generating ATP. These dephosphorylation reactions are energy-releasing steps that contribute to the net ATP production during glycolysis.
  19. 19. b) False – True – False – True. The bundle cap of dicot stems is composed of sclerenchyma, not parenchyma, making the first statement false. The bundle cap is indeed parenchymatous in some cases, but more accurately it is sclerenchymatous, making the second statement true. The bundle sheath of dicot leaves is sclerenchymatous, but the statement about endodermis being the outermost layer of stele is false; the pericycle is the outermost layer of the stele. In angiosperms, the pericycle does give rise to lateral roots, making the fourth statement true.
  20. 20. Plant A, exhibiting whiptail disease, is deficient in the mineral molybdenum (Mo). Molybdenum is a crucial component of enzymes like nitrogenase and nitrate reductase, which are vital for nitrogen metabolism in plants. Its deficiency leads to characteristic symptoms such as the distortion and necrosis of young leaves, particularly the lamina, giving them a 'whiptail' appearance. Plant B, showing little leaf disease, is deficient in the mineral zinc (Zn). Zinc is involved in the synthesis of auxin, a plant hormone responsible for cell elongation and growth, and is also a cofactor for various enzymes. A deficiency in zinc results in stunted growth, small and distorted leaves, and shortened internodes, hence the term 'little leaf disease'.
  21. 21. Several air pollutants significantly affect the rate of photosynthesis by damaging the photosynthetic apparatus and interfering with metabolic processes. Sulfur dioxide (SO2) is a major air pollutant that enters leaves through stomata and damages chloroplasts, reducing photosynthetic efficiency. Nitrogen dioxide (NO2) similarly impairs photosynthesis by causing oxidative stress and damaging cellular structures. Ozone (O3) is a highly reactive oxidant that damages cell membranes and chloroplast structures, leading to decreased photosynthetic rates. Smog, which is a mixture of various pollutants including ozone, nitrogen oxides, and particulate matter, reduces light penetration and causes cumulative damage to photosynthetic tissues. These pollutants collectively reduce the availability of light, damage the photosynthetic machinery, and interfere with enzyme function, thereby decreasing the overall rate of photosynthesis in affected plants.
  22. 22. The correct evaluation of these statements is: (i) Poly-B hydroxybutyrate is indeed a microbial plastic produced by certain bacteria and is biodegradable, making this statement True. (ii) Transduction refers to the transfer of DNA from one bacterium to another via bacteriophages, not direct bacterial transfer, making this statement False. (iii) Micrococcus is an obligate aerobe that requires oxygen to survive, making this statement True. (iv) Spirulina is rich in proteins and other nutrients, not primarily carbohydrates, and is used as a nutritional supplement and alternative food source, making this statement False. The correct answer is True, False, True, False.
  23. 23. The correct answer is c) C-D-B-A. The correct matching is as follows: Sapwood corresponds to Albumum (C), which is the living outer wood that actively transports water and minerals. Heartwood corresponds to Duramen (D), which is the non-functional inner wood that provides structural support. Porous wood corresponds to Hardwood (B), which typically has smaller vessels and is denser. Nonporous wood corresponds to Softwood (A), which has larger vessels and is less dense. These distinctions are important in understanding wood structure and its commercial applications.
  24. 24. Puffballs, Toadstools, Birds nest’s fungi, Bracket fungi, Smuts Rusts, Smuts.
  25. 25. Cytoplasmic streaming refers to the continuous movement and circulation of cytoplasm along with its suspended cellular materials, organelles, and dissolved substances within the cell. This dynamic process involves the flowing motion of the cytoplasm in a specific direction, typically around the vacuole in plant cells or throughout the cytoplasm in animal cells. Cytoplasmic streaming facilitates the distribution of nutrients, gases, and other essential substances to different parts of the cell, ensuring efficient cellular metabolism and transport. It also aids in the movement of organelles such as mitochondria and chloroplasts to regions where they are needed most. This streaming motion is driven by the interaction of actin filaments and myosin proteins in the cytoskeleton, and it is particularly visible in plant cells with large vacuoles.
  26. 26. Human hair is made primarily of protein, particularly a fibrous protein called keratin. The structure and texture of hair, including whether it is curly or straight, depends on the arrangement and bonding of these protein molecules. The distance between sulfur atoms in the protein chains is crucial in determining hair curliness. Sulfur atoms form disulfide bonds (also called disulfide bridges) between adjacent protein chains, which act as cross-links. When sulfur atoms are closer together, the protein chains are pulled tighter, causing the hair to curl more. Conversely, when sulfur atoms are farther apart, the protein chains are more relaxed, resulting in straighter hair. The number and positioning of these disulfide bonds determine the degree of curliness. This is why chemical treatments like perming or straightening work by breaking and reforming these disulfide bonds to alter the natural curl pattern of hair.
  27. 27. The correct matching is: Plasmid corresponds to A (a small, circular, double-stranded DNA molecule found in bacteria), Heterocyst corresponds to B (a specialized nitrogen-fixing cell in cyanobacteria), Glycocalyx corresponds to D (a layer of polysaccharides surrounding the cell wall), and Mesosome corresponds to C (an infolding of the bacterial cell membrane involved in DNA replication and respiration). The answer is B-A-D-C.
  28. 28. (d) Deoxyribose sugar – Phosphate Nitrogen base – Nucleotide
  29. 29. To relate on the basis of common features To define, on the basis of salient features To know the relationship among different groups. To understand evolutionary relationship.
  30. 30. Thylakoid membrane contains photosystem I (PSI) and photosystem II (PSII) PS I is unstacked region of granum tàcing stroma ofchÍoroplast. PS II is found in stacked region of thylakoid membrane facing lumen of thylakoid. Each photosystem consists of central core complex (CC) and light harvesting complex (LHC) or Antenna molecules. The core complex consists of respective reaction centre associated with proteins, electron donors and acceptors. PSI – CCI consists of reaction centre P 700 and LHC – I PS II- CC II consists of reaction centre P680 and LHC – II Light harvesting complex consists of several chiorophylls, carotenoids and xanthophyll molecules. The main function of LHC is to harvesting light energy and transfer it to their respective reaction centre.
  31. 31. In the desert, as well seashore regions the climatic condition remain the same throughout the year. Secondary growth in plants is influenced by seasonal changes since in these areas seasonal changes are not significant enough to bring in distinct Annual rings with early and latewood formation alternatively.
  32. 32. a. Definition: A symbolic association of algae and Fungi helping each other & living together known as lichens. b. Partners: Algal partner known as Phycobiont & Fungal partner known as Mycobiont c. Role of Algal partner – Autotrophic prepare food – give nutrition to fungal partner also d. Role of fungal partner – gives protection- helps in fixing to the substratum by rhizines. Classification: Character Phycobiont Mycobiont 1 Asexual reproduction Akinetes, hormogonia, Aplanospore, etc. fragmentation soredia, and isidia 2 Sexual reproduction absent sexual reproduction by ascocarp & ascospores Character Classification of lichens 1. Habitat Corticolous – growing on the bark Lichnicolous – growing on wood Saxicolous – growing on rock Terricolous – growing on the ground Marine – siliceous rock sea Freshwater – siliceous rocks (freshwater habitat). 2. Morphology of thallus Leprose – distinct fungal layer absent Crustose – crust like Foliose – Leaf-like Fruticose-branched pendulous shrub-like 3. On the basis of the distribution of algae cells Homoiomerous – Algae cells evenly distributed Heteromerous – A distinct layer of Algae and Fungi present 4. On the basis of the fungal partner If it is Ascomycetes – Ascolichen If it is basidiomycetes-Basidiolichen Economic importance: Secretion of acids of lichens Uses 1 Oxalic acid Weathering of rocks Pioneers in xerosere 2 Usnic acid Antibacterial II. a. Pollution Indicators – Lichens sensitive to air pollutants- (pollution indicators) b. Rocella Montagne – Produces a dye used in litmus paper (acid-base indicator) c. Cladonia rangiferina – Food for animals in tundra regions Part – II. 11th Bio Botany Guide Living World Additional Important Questions and Answers Choose The Right Answer:
  33. 33. The haplontic and diplontic life cycles represent two different patterns of alternation of generations in organisms. In the haplontic life cycle, the gametophyte phase is dominant and photosynthetically independent, representing the main vegetative body of the organism. The sporophyte phase is recessive and represented only by the zygote. When the zygote undergoes meiosis, haploidy is restored, and the haploid gametophyte develops again. Examples of organisms with haplontic life cycles include Volvox and Spirogyra. In contrast, the diplontic life cycle has a dominant sporophytic phase that is photosynthetically independent and represents the main vegetative body. The gametophyte phase is recessive and represented by single to few-celled structures such as gametes or gametophytes. The zygote develops into the dominant sporophyte through mitotic divisions. Examples of organisms with diplontic life cycles include Fucus, gymnosperms, and angiosperms. These two life cycle patterns represent fundamentally different strategies for alternation of generations, with the dominant phase being haploid in haplontic organisms and diploid in diplontic organisms.
  34. 34. Xylary fibres are specialized sclerenchymatous cells that are associated with the secondary xylem tissue, providing mechanical strength and support to the plant. These fibres are derived from the vascular cambium during secondary growth. There are four main types of xylary fibres, each with distinct characteristics: Libriform fibres are typically long, narrow, and possess simple pits, which are unbordered. Their secondary walls are heavily lignified, making them very strong. Fibre tracheids are generally shorter than libriform fibres and have moderate wall thickening. Their pits can be either simple or bordered, showing an intermediate structure between tracheids and libriform fibres. Septate fibres are unique because their lumen is divided into distinct chambers by thin, unlignified septa, which are cross-walls. An example of a plant with septate fibres is Teak. Lastly, Gelatinous fibres are characterized by having less lignin and a higher proportion of cellulose in their cell walls, often forming a thick, unlignified inner layer known as the G-layer. These fibres are highly flexible and are often found in tension wood.
  35. 35. The characteristic feature of DNA. * If one strand runs in the 5′ – 3′ direction, the other runs in 3′ – 5′ direction and thus are antiparallel (they run in the opposite direction). The 5′ end has the phosphate group and 3’end has the OH group. * The angle at which the two sugars protrude from the base pairs is about 120°, for the narrow-angle and 240° for the wide-angle. The narrow-angle between the sugars generates a minor groove and the large angle on the other edge generates major groove. * Each base is 0.34 nm apart and a complete turn of the helix comprises 3.4 nm or 10 base pairs per turn in the predominant B form of DNA. * DNA helical structure has a diameter of 20 Å and a pitch of about 3 Å. X-ray crystal study of DNA takes a stack of about 10 bp to go completely around the helix (360°). * Thermodynamic stability of the helix and specificity of base pairing includes * The hydrogen bonds between the complementary bases of the double helix * stacking interaction between bases tend to stack about each other perpendicular to the direction of the helical axis. * Electron cloud interactions (\({ \Pi -{ \Pi } }\)) between the bases in the helical stacks contribute to the stability of the double helix. * The phosphodiester linkages give an inherent polarity to the DNA helix. They form strong covalent bonds, gives strength and stability to the polynucleotide chain. * Plectonemic coiling – the two strands of the DNA are wrapped around each other in a helix, making it impossible to simply move them apart without breaking the entire structure. Whereas in paranemic coiling the two strands simply lie alongside one another, making them easier to pull apart. * Based on the helix and the distance between each turn, the DNA is of three forms – A DNA, B DNA and Z DNA.
  36. 36. Senescence is the process of aging in plants, and it is influenced by various internal and external factors. Abscisic acid (ABA) and ethylene are hormones that accelerate senescence, promoting the breakdown of cellular components and the aging process. In contrast, auxin and cytokinin are growth-promoting hormones that reduce or retard senescence, helping to maintain plant vigor and delay aging. Nitrogen deficiency accelerates senescence as nitrogen is essential for protein synthesis and maintaining cellular functions, while adequate nitrogen supply retards the senescence process. High temperatures in vernalized seeds accelerate senescence, whereas low temperatures retard it, as cold conditions slow down metabolic processes. Water stress is another significant factor that accelerates senescence through the accumulation of abscisic acid, which triggers senescence-related changes in plant tissues. These factors work together to regulate the timing and rate of senescence, which is crucial for plant survival and reproduction.
  37. 37. Kranz anatomy, also known as dimorphism of chloroplasts, is a distinctive structural feature observed in C4 plants that is absent in C3 plants. In C4 plants, the leaves show a characteristic two-celled photosynthetic system with different types of chloroplasts in different cell types. The bundle sheath cells, which surround the vascular bundles, contain larger chloroplasts with thylakoids that are free and not arranged in grana, appearing more like loose stacks. In contrast, the mesophyll cells contain smaller chloroplasts with thylakoids arranged in grana, similar to those found in C3 plants. This anatomical differentiation is functionally significant because the two cell types perform different roles in the C4 photosynthetic pathway: mesophyll cells perform the initial CO2 fixation, while bundle sheath cells carry out the subsequent reactions. C3 plants lack this specialized anatomy and possess only one type of chloroplast distributed uniformly in both mesophyll and bundle sheath cells. The Kranz anatomy in C4 plants is an adaptation that enhances photosynthetic efficiency and reduces photorespiration in hot and dry environments.
  38. 38. Diffuse porous wood is a type of wood where the vessels, which are responsible for water transport, are more or less uniform in diameter and are evenly distributed throughout the annual ring. This type of wood is typically formed in plants that grow in regions with uniform climatic conditions, meaning there are no significant seasonal variations in temperature or water availability. As a result, the growth rate of the plant is relatively consistent throughout the growing season, leading to a homogeneous distribution of vessels. Ring porous wood, in contrast, is characterized by a distinct difference in vessel size within an annual ring. The vessels formed early in the growing season (earlywood) are typically much wider and more numerous, forming a prominent ring, while the vessels formed later in the season (latewood) are narrower and less abundant. This pattern is common in plants growing in climates with distinct seasonal changes, where rapid water transport is required during the spring growth flush, followed by reduced transport during drier or colder periods. Consequently, the vessels are not uniformly distributed throughout the wood, with larger vessels concentrated in the earlywood.
  39. 39. Diffusion is the net movement of molecules from a region of their higher concentration to a region of their lower concentration along a concentration gradient, continuing until an equilibrium is attained. This process occurs spontaneously without the input of energy and is driven by the random thermal motion of molecules. In a region of high concentration, molecules are more densely packed and have a higher probability of moving toward regions of lower concentration simply due to random molecular movement. Over time, as molecules move from high to low concentration regions, the concentration difference decreases until the molecules are uniformly distributed throughout the available space, at which point equilibrium is reached and net diffusion ceases. Diffusion is a fundamental process in plant physiology and occurs across cell membranes, through cell walls, and in intercellular spaces. It is responsible for the movement of various substances including gases such as oxygen and carbon dioxide, dissolved nutrients, and other small molecules. The rate of diffusion is influenced by several factors including the concentration gradient, the temperature of the system, the size of the diffusing molecules, and the nature of the medium through which diffusion occurs. In plants, diffusion plays a crucial role in gas exchange during photosynthesis and respiration, in the movement of nutrients from the soil into root cells, and in the distribution of various substances within plant tissues. Although diffusion is a passive process that does not require metabolic energy, it is essential for maintaining the chemical gradients and concentrations of substances necessary for plant survival and function.

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