Tag: chemical coordination in plants
Questions Related to chemical coordination in plants
The hormone present in higher concentration in fruits and seeds is
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Auxin
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Gibberellin
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Cytokinin
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Ethylene
Auxin promotes stem elongation. It is present in high concentration in apical meristem. Gibberellin controls shoot elongation, seed germination and delay the senescence in leaves and fruit. Cytokinin promotes cell growth and division. It is present in higher concentration in developing areas such as young fruits and seeds. Ethylene helps in fruit ripening, senescence and abscission.
Choose the right from the following.
i. In light, hormone auxin, helps the cells to grow longer in plants .
ii. Plant hormone gibberellins helps in growth of a stem.
iii. Cytokinins inhibits cell division.
iv. Abscisic acid promote growth in plants.
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Option i and iii are correct.
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Option ii and iv are correct.
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Option i and ii are correct.
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Option i and iv are correct.
Plants have certain chemical substances in them that transmit messages for maintaining different functions of the body.
The plant hormone that promote cell division
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Abscisic acid
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Auxins
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Gibberellins
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Cytokinins
Abscisic acid is a plant growth hormone involved in seed dormancy and responses of plants to stress. This makes option A incorrect. Auxins promote the formation of lateral and adventitious roots, regulate the flower bud development and induce vascular differentiation. This makes option B incorrect. Gibberellins are responsible for stem elongation, breaking seed dormancy, mobilization of endosperm reserves as well as regulate sex determination, flower initiation and fruit set. This makes option C incorrect. Cytokinins are the plant growth hormones that regulate the cell division in root and shoot of the plant both in vivo and in vitro. They do so by regulating the controls that govern the transition of the cell from one stage of the cell cycle to the next one. This makes option D correct.
The growth regulator that retards ageing of plant organs is
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Auxin
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Gibberellin
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Cytokinin
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Abscisic acid
Cytokinin is the plant growth regulator which promotes cell division. The hormone retards the process of ageing which is known as senescence. There is stimulation for the production of chlorophyll and the fruits and leaves are prevented from falling. There is breaking of the bud dormancy which allows reproductive growth in the plants.
The growth regulator that retards ageing of plant organs is
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Auxin
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Gibberellin
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Cytokinin
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Abscisic acid
Cytokinins delay destruction of chlorophyll and proteins and thereby delaying the leaf senescence/ageing. Thus, option C is correct .
Which one of the following is primarily concerned with cell division ?
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GA$ _3$
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IAA
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Cytokinin
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NAA
Cytokinins are the plant growth hormones that regulate the cell division in root and shoot of the plant both in vivo and in vitro. They do so by regulating the controls that govern the transition of the cell from one stage of the cell cycle to the next one. Thus, option C is correct
Chemically, cytokinins are related to
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Carotenoid
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Terpenes
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Aminopurines
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Indole
Cytokinins are the growth substances which act primarily on cell division and have little or no effect on extension growth. Cytokinins are derivatives of purine base, adenine, bearing furfuryl substituent. Thus option C is the correct answer.
The growth regulator that retards ageing of plant organs is called as
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Auxin
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Gibberellin
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Cytokinin
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Abscisic acid
Cytokinins have a striking quality to retard senescence (i.e., process of ageing) in plants. External application of cytokinins delay the rate of chlorophyll disappearance and protein degradation which usually accompanies the process of senescence in leaves.
Induction of cell division and delay in senescence is done by
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Cytokinins
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Auxins
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Gibberellic acid
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CoA
Cytokinins stimulate cell division, even in non-meristematic cells, in presence of auxin. They are most abundant in the growing tissues which are active site of cell division, for example: root, embryos, fruits etc. Cytokinins delay senescence of leaves via their effect on translocation of metabolites and by reducing breakdown of proteins and chlorophyll (the Richmond-Lang effect). Option A is correct. Cytokinins treated leaves withdraw their nutrients from adjacent leaves and maintain their viability. Option C is incorrect as gibberellins (GA) cause cell elongation. Treatment with gibberellins causes bolting (stem elongation) and reverses dwarfism by increasing the intermodal length. Exogenous application of gibberellins prevents senescence in leaves and fruits. Auxin serves as inhibitor of leaf senescence by inhibiting synthesis of abscission layer at the base of petiole or pedicel which in turn causes leaf shedding. Option B is incorrect as auxin is the hormone of cell division and cell expansion both. CoA is a coenzyme which is involved in many metabolic activities like synthesis and oxidation of fatty acid. This makes option D incorrect as CoA is not a plant growth hormone
Which of the following hormone induces cell division?
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Auxin
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Gibberellin
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Cytokinin
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Trypsin
Cytokinins stimulate cell division, even in non-meristematic cells, in presence of auxin. They are most abundant in the growing tissues which are active site of cell division, for example: root, embryos, fruits etc. This makes option C correct. Option A is incorrect as auxins are the growth hormones that cause cell division as well as cell expansion, thereby causing growth while cytokinins are not involved in cell expansion but only in cell division. Option B is incorrect as gibberellins cause cell elongation. Treatment with gibberellins causes bolting (stem elongation) and reverses dwarfism by increasing the intermodal length. Trypsin is a globular protein with 24kD and one polypeptide chain of 220 residues and serves as proteolytic enzyme (protein digesting enzyme). Option D is incorrect.