TEST BORRADO, QUIZÁS LE INTERESE: fisioveg
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fisioveg Descripción: tema 9 al 11 Autor:
Fecha de Creación: 14/05/2024 Categoría: Otros Número Preguntas: 20 |
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What does determine where the next leaf primordium will be initiated in the shoot apical meristem? Leaf primordia appear randomly as a consequence of spatial constraints in the shoot apical meristem. An auxin maxima generated by polar auxin transport A cytokinin maxima generated when auxin is transported away from the shoot apical meristem. A gibberellin maxima generated by selective degradation of bioactive GAs
. Auxins are essential during embryogenesis for the correct establishment of the apical-basal axis of the embryo. True or false? False, during embryogenesis, cells are in a quiescent state so there is no hormone synthesis at this moment. False, auxin concentration is very low in the developing embryo and only increases after it has reached the torpedo stage. True, polar auxin transport generates auxin maxima that will point where the cotyledons and the root apical meristem will be located in the embryo. False, the embryo axis is established where auxins are degraded and inactivated so cell division does not occur. . Gibberellins (GAs) are synthesized by the terpenoid pathway. The three stages of GA biosynthesis takes place in three different subcellular localizations: plastids, endoplasmic reticulum and nucleus. plastids, endoplasmic reticulum and cytosol. mitochondria, endoplasmic reticulum and cytosol. plastids, mitochondria and cytosol. The folding of the leaves in the dark is an example of nyctinastic movement. This movement is mediated by: Irreversible cell death of ventral and dorsal motor cells of a specialised organ called pulvinus. Changes in turgor of the dorsal and ventral cells forming an organ called pulvinus. Phosphorylation of MAP kinases in dorsal and ventral cells of the pulvinus. Sequential activation of the proteasome and degradation of specific proteins in the ventral and dorsal cells of the pulvinus. Indicate which of the following would be a good choice as a biotechnological tool for the inhibition of fruit ripening during storage. Limiting ethylene production by increasing the carbon dioxide concentration. Exogenous application of gibberellins. Exogenous application of ethylene. Limiting ethylene production by increasing the oxygen concentration. . Individual plants can alert neighbouring plants when they are attacked by pathogens. True or false? False, pathogen attack triggers an hypersensitive reaction that results in plant cell death. True, they synthesize volatile compounds, such as methyl salicylate, that diffuses in the air and is perceived by neighbouring plants. False, signals triggering pathogen resistance are only transported to other parts of the same plant via the phloem. True, they synthesize volatile compounds such as salicylic acid and jasmonic acid that can diffuse in the air and are perceived by neighbouring plants. . In Arabidopsis roots, auxin has been shown to promote the degradation of a repressor involved in gibberellin signal transduction. In this case, the relation between these two signaling pathways would be an example of: Tertiary cross-regulation between the auxin and the gibberellin signaling pathway. Independent action of two hormones (auxin and gibberellin) on the same developmental process Primary cross-regulation between the auxin and the gibberellin signaling pathway. Secondary cross-regulation between the auxin and the gibberellin signaling pathway. Complete the sentence: ____________ is a photoreceptor that is able to absorb red and far red light, contains phytochrommobilin as a chromophore and displays kinase activity when active. Pregunta 8 Resposta Phytochrome Cryptochrome A nyctinastic photoreceptor Phototropin. In order to generate transgenic plants, we modify the T-DNA region of the Ti plasmid of Agrobacterium tumefaciens. We replace those genes controlling _______1_____ and ______2_____ synthesis and introduce our gene of interest and a gene conferring _____3______ resistance. 1.abscisic acid 2. jasmonic acid 3. hormone 1. infection 2. bacterial resistance 3. stress 1. opine synthesis 2. hormone synthesis 3. antibiotic 1. antibiotic resistance 2. hormone synthesis 3. drought . Which of the following sentences is correct regarding cytokinin homeostasis. Cytokinins are inactivated by conjugation with different amino acids. Cytokinins, together with auxins, are the only hormones that are display polar transport. Isopentenyl transferase catalizes the synthesis of isopentenyl adenine, one of the bioactive cytokinins. Cytokinin oxidase degrades bioactive cytokinins irreversibly. . Which phytohormone is involved in inducing plant responses to drought stress? Auxin Cytokinins Gibberellins Abscisic acid . You have decapitated a four-week-old pea plant. Which would be the consequence of this manipulation and why? The axillary meristems located at the axils of the leaves will become active and form new branches. Decapitation has removed the source of auxin that under normal circumstances inhibits branching. Decapitation stimulates lateral root formation by promoting strigolactone synthesis. New roots will help alleviate the stress generated by removal of the shoot apical meristem. Gibberellin synthesis is stimulated and volatile molecules synthesised. Those molecules warn neighbouring plants for a potential pathogen attack. Decapitation kills the plant since the shoot apical meristem, structure that has been removed, is responsible for the formation of the whole aerial part of the plant. . Cells at the shoot apical meristem can be classified into three different regions: the central zone, the peripheral zone and the rib meristem. Indicate the correct option. Cells from the rib meristem will give rise to the leaf primordia. Cells in the central zone divide very actively in order to produce enough cells to generate all the aerial part of the plant. Cells from the rib meristem will give rise to the central stem and the vascular tissue. Cells from the peripheral zone divide actively, maintaining a stable population of stem cells. The amount of a particular bioactive hormone in a certain tissue and in a certain moment of the development will depend: only on the rate at which the hormone gets conjugated and inactivated on the relative ratio between synthesis and degradation enzymes, independently of transport. on the ratio of synthesis, degradation, inactivation through conjugation and transport. on the total concentration of the hormone since only 10% of this amount will be bioactive in a certain tissue in a particular developmental stage. . Which hormones are responsible for the control of shoot branching? Auxins, cytokinins and strigolactones. Auxins, gibberellins and strigolactones. Auxins, ethylene and abscisic acid. Auxins and polyamines. . Indicate which of the following sentences is correct regarding photo and skotomorphogenesis. Seedlings grown in light experience photomorphogenesis: the hypocotyl elongates quickly to maximize light absorbtion, cotyledons unfold and chlorophyll is actively synthesised. Seedlings grown in darkness experience skotomorphogenesis: the hypocotyl elongates, cotyledons unfold to protect the meristem and chlorophyll is actively synthesised. Seedlings grown in light experience skotomorphogenesis: hypocotyl elongation is inhibited, cotyledons unfold and chlorophyll is actively synthesised. Seedlings grown in darkness experience skotomorphogenesis: the hypocotyl elongates, cotyledons remain folded, an apical hook that protect the meristem is formed and cells do not accumulate chlorophyll. Which would be the difference between a mutant affecting the biosynthesis of a hormone and a mutant affecting the perception of the same hormone? The mutant affecting the perception of the hormone will display the mutant phenotype independently of the internal concentration of the hormone. Mutants affecting perception of hormones are always lethal since all hormones are crucial for developmental processes. The mutant affecting the biosynthesis of the hormone would never respond to exogenous application of the hormone. It is not possible to design an experiment to differentiate between those two types of mutants. . Phototropins are blue and UV-A light receptors that control stomata aperture and phototropism among others. are blue light receptors that control flowering. are red and blue light receptors that are essential for growth and development. are red light receptors that control stomata aperture and photomorphogenesis. You have isolated a mutant that shows an altered phototropic response: when illuminated with a lateral light the growth of the stem does not orientate towards the light but it continues to grow straight. Which of the following proteins it most probably the one affected by the mutation? The ethylene receptor. Gibberellin-20-oxidase, an enzyme participating in GA synthesis. An auxin carrier, involved in auxin transport. A cytokinin receptor. How do you explain the fact that the root displays positive gravitropism and the shoot negative gravitropism if in both cases this response is controlled by the same signal (auxin)? In the stem, statoliths move against the gravity and in the root they move in favour of gravity. Different tissues, shoot and root, display different sensitivity to auxin. The gravitropic response is triggered by auxin in the root but by a combination of auxin and gibberellins in the root. Auxin is transported in favor of its concentration gradient in the root and against it in the stem. . |
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