Is phytochrome a hormone?What are some of the major differences in action between phytochrome and auxin?
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Phytochrome is a chromoprotein whose state is influenced by light. It is mainly produced in darkness and exists first of all as PR (or P660; P is the abbreviation of phytochrome, R means reduced). \nPhytochrome is the photoreceptor that activates the de-etiolation (and many other) responses to red light and Phytochrome is a protein with a pigment molecule covalently bound
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a heterotroph obtains energy from food it consumes. This is opposed to an autotroph which obtains energy directly (such as a plant absorbing light energy).
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There are actually 2 types of chlorophyll, named a and b. They differ only slightly, in the composition of a sidechain (in a it is -CH3, in b it is CHO). Both of these two chlorophylls are very effective photoreceptors because they contain a network of alternating single and double bonds, and the orbitals can delocalise stabilising the structure. Such delocalised polyenes have very strong absorption bands in the visible regions of the spectrum, allowing the plant to absorb the energy from sunlight.\n\nThe different sidegroups in the 2 chlorophylls 'tune' the absorption spectrum to slightly different wavelengths, so that light that is not significantly absorbed by chlorophyll a, at, say, 460nm, will instead be captured by chlorophyll b, which absorbs strongly at that wavelength. Thus these two kinds of chlorophyll complement each other in absorbing sunlight. Plants can obtain all their energy requirements from the blue and red parts of the spectrum, however, there is still a large spectral region, between 500-600nm, where very little light is absorbed. This light is in the green region of the spectrum, and since it is reflected, this is the reason plants appear green. Chlorophyll absorbs so strongly that it can mask other less intense colours. Some of these more delicate colours (from molecules such as carotene and quercetin) are revealed when the chlorophyll molecule decays in the Autumn, and the woodlands turn red, orange, and golden brown. Chlorophyll can also be damaged when vegetation is cooked, since the central Mg atom is replaced by hydrogen ions. This affects the energy levels within the molecule, causing its absorbance spectrum to alter. Thus cooked leaves change colour - often becoming a paler, insipid yellowy green.
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Mainly plant growth is controlled by auxins, gibberellins, cytokinins, ethylene gas, abscisic acid. auxins help in growth of roots, gibberelins for shoot, cytokinins for cell elongation, cell multiplication, cell maturation, ethylene gas and abscisic acid are antagonistic and control the dropping of fruits, leaves etc
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Yes, there are. They are called Phytohormones(plant hormones). Some promote seed dormancy. (Cytokinin, Gibberelins, etc,)
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>>>if chloropyll is implanted in to an animal cell,would it\n>>>>> become auto trophic\n\nNo. \n\nAs Masyhur points out chlorphyll is just a tiny part of an incredibly complex system of pigments and enzymes needed to harvest light.  It is really akin to asking whether you could glue a carburettor to the side of a cardborad box and turn it into an airplane. \n\nA more plausible route would be to implant entire chlorplasts into an animal cell line. That has potential, but only for narrow range of animals.\n\nSee, the thing about chloroplasts is they need light to work. And the thing about most animals is that they have evolved pigments to stop light penetrating their cells. The two conditions are mutually exclsuive. You could implant or the chlorplasts you like into a human or cockroach and they won't do anyhting because they will be permanently in the dark.\n\nWith transparent animals like jellyfish or glass fish or similar you probably could achieve some level of autotrophic activity. \n\nIn the case of a highly active animal like a fish the payoff wouldn't be worth the cost. Chlorplasts require energy to build and maintain and active animals can't afford to laze around int he sun all day. That's why the ancestors of animals abandoned their chlorophyll in the first place (did you know that all animals are descended from photosyntheic organisms?)\n\nBut with slow moving animals like jellyfish it becomes more plausible. Some jellyfish already utilise symbiotic algae to harvest sunlight, so for those species the addition of inherent chlorpplasts could be a major boon.\n\n>>>>IS IT POSSIBLE \n\nNot with todays technology. However it is entirely possible we could have the technology to implant chlorplasts within our liftimes. I dont; quite see why we would bother, but still.....
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1. Plant cell are constantly differentiating in a plant, as long as it has embryonic tissure (i.e. buds). In these buds, embryonic cells are born, grow and differentitate into all sorts of plant cell types.\n2. Plants facilitate the process by bringing to these burgeoning cells all the nutrients they need in their infancy. This differentiation process is crucial because it creates all the different types of cell a plant needs to live, i.e. conducting cells, structure cells, photosynthetic cellls, root cells, etc.
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All plants have chlorophyll..........................
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just fyi i would have made this a biology question but anyway, chlorophyll a and b would be present in both leaves its not one or the other.  this sounds like homework don't you think that you should be figuring this out on your own.  i'll give you a couple hints.  you need a solute so that you can separate the pigments.  the pigments  will travel farther if the are less soluble.  Anyway thats all i'm giving you good luck.
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It is because of a plant hormone and also becasue plants are sensitive to light moisture and gravity.  shoots or stamp grow towards light and against the force if gravity.  roots grow towards moisture and in the direction of gravity.\n\nIn the shoot, hormone collects on the lower side and stimualtes the growth of the cells on this side.  therefore the shoot grows upwards and away from the force of gravity.\n\nin the root, the hormone also collects on the lower side buts slows down the growth of the the cells on this side.  therefore the roots grows downwards and towards the force of gravity.
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D is the correct answer, Light enables photosynthesis so a and c are wrong, and no reaction can increase exponentially as in B
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There are light sensitive auxins (growth hormones in plants) present in the plant tips. The side facing light causes accumulation of auxins on the opposite side thus promoting growth at that region. These auxins accumulate on the side where light is least but at the tip of the plant.Eg. when there is light on the left, auxins concentrate on the right and promote growth on the right. Since the right elongates and the left doesn't, the plant incline/bends to the left.\n\nThis is called phototropism.
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In the whole autonomic nervous system there are 3 main hormones/neurotransmitters\n\n1)Adrenaline\n2)Noradrenaline\n3)Acetylcholine\n\nAdrenaline/Noradrenaline both stimulate the same receptors (alpha and beta adrenergic) but to different extents. (Think ADRENaline = ADRENergic. Both adrenaline and noradrenaline have ADREN in their name) AcetylCHOLINE stimulates CHOLINErgic receptors\n\nAll these transmitters are found in both the sympathetic and parasympathetic branches of the autonomic system
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auxines will have a positive effect on the root growth and is especially usefull for regeneration (like you take a leaf, but it in water, add auxines, and after a while roots may appear and you have a new plant (a clone))
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Chlorophyll a and b absorb very little light in the green range but are very active in the absorption of blue and red light. \nChlorophyll b is bluish-green, and carotenoids are red, orange, and yellow. Accessory pigments are different colors than the green chlorophyll a and, therefore, extend the range of light used for photosynthesis by absorbing wavelengths missed by chlorophyll a.
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Hormonal activity is usually a negative feed back mechanism. You would think exercise would feed forward, though, as the rate would keep increasing. Not my area, though, so a functional biologist is needed here.
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Photosystems (ancient Greek: phos = light and systema = assembly) are protein complexes involved in photosynthesis. They are made of several protein subunits, as well as hundreds of cofactors, and act as large complex. In the process of photosynthesis, light is absorbed by a photosystem to begin an energy-producing reaction. The photosytems are contained within the chloroplasts in the leaves of plants. Two types of photosystems exist: photosystem I (P700) and photosystem II (P680). Each photosystem is differentiated by the wavelength of light to which it is most reactive (700 and 680 nanometers, respectively), and the type of terminal electron acceptor. Type I photosystems use ferredoxin-like iron-sulfur cluster proteins as terminal electron acceptors, while type II photosystems ultimately shuffle electrons to a quinone terminal electron acceptor.\nStructure\n\nA photosystem is made up of a reaction center pigment of chlorophyll a and numerous antenna pigments and proteins. Because chlorophyll a can only absorb light of a narrow wavelength, it works with the antenna pigments to gain energy from a larger part of the spectrum. The pigments absorb light of various wavelengths and pass along their gained energy to the reaction center chlorophyll. When the energy reaches the chlorophyll a, it releases two electrons into an electron transport chain.\n\nThough chlorophyll a normally has an optimal absorption wavelength of 660 nanometers, it associates with different proteins in each type of photosytem to slightly shift its optimal wavelength, producing two distinct photosystem types. Other proteins serve to support the structure and electron pathways in the photosystem.\n\n Relationship between Photosystems I and II\n\nHistorically photosystem I was named one since it was discovered before photosystem II but this does not represent the order of the electron flow.\n\nWhen photosystem II absorbs light, electrons in the reaction-centre chlorophyll are excited to a higher energy level and are trapped by the primary electron acceptors. To replenish the deficit of electrons, electrons are extracted from water (either through photolysis or enzymatic means) and supplied to the chlorophyll.\n\nPhotoexcited electrons travel to photosystem I through an electron transport chain set in the thylakoid membrane. This energy fall is harnessed, (the whole process termed chemiosmosis), to transport H+ ions through the membrane to provide a proton-motive force to generate ATP. If electrons only pass through once, the process is termed noncyclic photophosphorylation.\n\nWhen the electron reaches photosystem I it fills the electron deficit of the reaction-centre chlorophyll of photosystem I. The deficit is due to photo-excitation of electrons which are again trapped in an electron acceptor molecule, this time that of photosystem I.\n\nThese electrons may either go through the aforementioned electron transport chain again in which case it is termed cyclic photophosphorylation. Otherwise the electrons pass down another electron transport chain which ends at an enzyme, NADP+ reductase. Electrons and hydrogen ions are added to NADP+ to form NADPH. This reducing agent is transported to the Calvin cycle to react with glycerate 3-phosphate, along with ATP to form glyceraldehyde 3-phosphate, the basic building block from which plants can make a variety of substances.