Ib qho ntawm qhov sib txawv tseem ceeb ntawm cov nroj tsuag thiab tsiaj txhu yog qhov muaj nyob hauv cytoplasm ntawm thawj cov kab mob xws li plastids. Cov qauv, cov yam ntxwv ntawm lawv cov txheej txheem tseem ceeb, nrog rau qhov tseem ceeb ntawm chloroplasts, chromoplasts thiab leukoplasts yuav tau tham hauv kab lus no.
Chloroplast qauv
Green plastids, cov qauv uas peb yuav kawm tam sim no, muaj nyob rau hauv lub luag haujlwm organelles ntawm cov hlwb ntawm ntau dua spore thiab noob nroj tsuag. Lawv yog ob-membrane cellular organelles thiab muaj cov duab oval. Lawv tus lej hauv cytoplasm tuaj yeem sib txawv. Piv txwv li, cov hlwb ntawm columnar parenchyma ntawm nplooj nplooj ntawm cov luam yeeb muaj txog li ib txhiab chloroplasts, nyob rau hauv cov stems ntawm cov nroj tsuag ntawm cereal tsev neeg los ntawm 30 mus rau 50.
Ob daim nyias nyias uas tsim cov organoid muaj cov qauv sib txawv: sab nrauv yog du, peb txheej, zoo ib yam li daim nyias nyias ntawm cov nroj tsuag ntawm tes. Sab hauv muaj ntau cov quav hu ua lamellae. Nyob ib sab ntawm lawv yog cov hnab tiaj tus - thylakoids. Lub lamellae tsim ib lub network ntawmparallel tubules. Nruab nrab ntawm cov lamellae yog thylakoid lub cev. Lawv tau sau rau hauv pawg - cov nplej uas tuaj yeem txuas rau ib leeg. Lawv tus lej hauv ib chloroplast yog 60-150. Tag nrho cov kab noj hniav sab hauv ntawm chloroplast yog ntim nrog matrix.
Organella muaj cov cim qhia ntawm nws tus kheej: nws cov khoom siv los ntawm nws tus kheej - DNA ncig, ua tsaug rau cov chloroplasts tuaj yeem sib ntxiv. Kuj tseem muaj qhov kaw sab nrauv uas txwv cov organelle los ntawm cov txheej txheem tshwm sim hauv cytoplasm ntawm lub cell. Chloroplasts muaj lawv tus kheej ribosomes, i-RNA thiab t-RNA molecules, uas txhais tau hais tias lawv muaj peev xwm ntawm protein synthesis.
YThylakoid functions
Raws li tau hais ua ntej, cog cell plastids - chloroplasts - muaj cov hnab ntim tshwj xeeb hu ua thylakoids. Pigments tau pom nyob rau hauv lawv - chlorophylls (kev koom tes hauv photosynthesis) thiab carotenoids (ua haujlwm txhawb nqa thiab trophic). Kuj tseem muaj cov kab ke enzymatic uas muab cov kev cuam tshuam ntawm lub teeb thiab tsaus theem ntawm photosynthesis. Thylakoids ua raws li cov kav hlau txais xov: lawv tsom lub teeb quanta thiab coj lawv mus rau chlorophyll molecules.
Photosynthesis yog cov txheej txheem tseem ceeb ntawm chloroplasts
Autotrophic hlwb muaj peev xwm ntawm nws tus kheej ua ke cov organic tshuaj, tshwj xeeb yog qabzib, siv carbon dioxide thiab lub teeb lub zog. Ntsuab plastids, uas nws lub luag haujlwm peb tab tom kawm tam sim no, yog ib feem tseem ceeb ntawm phototrophs - cov kab mob ntau yam xws li:
- ntau dua cov nroj tsuag (mosses, horsetails, club mosses,ferns);
- noob (gymnosperms - ginga, conifers, ephedra thiab angiosperms lossis paj ntoo).
Photosynthesis yog ib txoj hauv kev ntawm cov tshuaj tiv thaiv redox, uas yog raws li cov txheej txheem ntawm kev hloov hluav taws xob los ntawm cov khoom pub dawb mus rau cov tebchaw uas "tau txais" lawv, lub npe hu ua.
Cov tshuaj tiv thaiv no ua rau muaj kev sib txuas ntawm cov tshuaj organic, tshwj xeeb yog cov piam thaj, thiab tso tawm cov pa oxygen molecular. Lub teeb theem ntawm photosynthesis tshwm sim ntawm thylakoid membranes nyob rau hauv qhov kev txiav txim ntawm lub teeb lub zog. Lub teeb absorbed quanta excite cov electrons ntawm magnesium atoms uas tsim cov xim ntsuab - chlorophyll.
Lub zog ntawm electrons yog siv rau kev sib txuas ntawm cov khoom siv hluav taws xob: ATP thiab NADP-H2. Lawv tau cleaved los ntawm lub xovtooj ntawm tes rau cov theem tsaus ntuj tshwm sim tshwm sim hauv chloroplast matrix. Kev sib xyaw ua ke ntawm cov tshuaj tiv thaiv hluavtaws no ua rau tsim cov molecules ntawm qabzib, amino acids, glycerol thiab fatty acids, uas yog lub tsev thiab trophic khoom ntawm tes.
Plastid yam
Ntsuab plastids, cov qauv thiab kev ua haujlwm ntawm peb tau tham ua ntej, pom muaj nyob hauv nplooj, ntsuab stems thiab tsis yog tib hom. Yog li, nyob rau hauv daim tawv nqaij ntawm cov txiv hmab txiv ntoo, nyob rau hauv lub petals ntawm flowering nroj tsuag, nyob rau hauv lub txheej npog ntawm underground tua - tubers thiab qhov muag teev, muaj lwm yam plastids. Lawv hu ua chromoplasts lossis leucoplast.
Colorless organelles (leucoplast) muaj qhov sib txawv thiab txawv ntawm chloroplasts nyob rau hauv uas lawvlub puab kab noj hniav tsis muaj nyias daim hlau - lamellae, thiab tus naj npawb ntawm thylakoids rau hauv lub matrix yog me me. Lub matrix nws tus kheej muaj deoxyribonucleic acid, protein-synthesizing organelles - ribosomes thiab proteolytic enzymes uas zom cov proteins thiab carbohydrates.
Leucoplasts kuj muaj enzymes - synthetases koom nrog hauv kev tsim cov hmoov txhuv nplej siab los ntawm cov piam thaj. Yog li ntawd, cov nroj tsuag tsis muaj xim plastids khaws cia cov as-ham: protein granules thiab starch nplej. Cov plastids, uas nws lub luag haujlwm yog txhawm rau khaws cov organic, tuaj yeem hloov mus rau hauv chromoplasts, piv txwv li, thaum lub sij hawm ripening ntawm txiv lws suav uas nyob rau theem ntawm milky ripeness.
Raws li qhov kev daws teeb meem scanning microscope, qhov sib txawv ntawm cov qauv ntawm tag nrho peb hom plastids tau pom meej meej. Qhov no, ua ntej ntawm tag nrho cov, txhawj xeeb txog chloroplasts, uas muaj cov txheej txheem nyuaj tshaj plaws cuam tshuam nrog kev ua haujlwm ntawm photosynthesis.
Chromoplasts - xim plastids
Nrog rau cov nroj tsuag ntsuab thiab tsis muaj xim, muaj peb hom organelle hu ua chromoplasts. Lawv muaj ntau yam xim: daj, ntshav, liab. Lawv cov qauv zoo ib yam li leukoplasts: lub puab daim nyias nyias muaj me me ntawm lamellae thiab ib tug me me ntawm thylakoids. Chromoplasts muaj ntau yam xim: xanthophylls, carotenes, carotenoids, uas yog cov pab pawg photosynthetic. Nws yog cov plastids uas muab cov xim ntawm cov hauv paus hniav ntawm beets, carrots, txiv hmab txiv ntoo ntoo thiab berries.
Yuav ua li cas lawv tshwm simthiab mutual transform plastids
Leucoplasts, chromoplasts, chloroplasts yog plastids (cov qauv thiab kev ua haujlwm uas peb tab tom kawm) uas muaj cov hauv paus chiv keeb. Lawv yog cov derivatives ntawm meristematic (kev kawm ntawv) cov ntaub so ntswg, los ntawm uas protoplastids yog tsim - ob-membrane sac-zoo li organelles txog li 1 micron loj. Nyob rau hauv lub teeb, lawv nyuaj rau lawv cov qauv: ib tug puab membrane uas muaj lamellae yog tsim, thiab cov xim ntsuab chlorophyll yog synthesized. Protoplastids ua chloroplasts. Leukoplasts tseem tuaj yeem hloov pauv los ntawm lub teeb lub zog rau hauv ntsuab plastids thiab tom qab ntawd mus rau hauv chromoplasts. Kev hloov pauv Plastid yog qhov tshwm sim thoob plaws hauv ntiaj teb cov nroj tsuag.
Chromatophores ua ntej ntawm chloroplasts
Prokaryotic phototrophic kab mob - cov kab mob ntsuab thiab ntshav, ua cov txheej txheem ntawm photosynthesis nrog kev pab los ntawm bacteriochlorophyll A, cov molecules uas nyob rau sab hauv outgrowths ntawm lub cytoplasmic membrane. Microbiologists suav cov kab mob chromatophores ua ntej ntawm plastids.
Qhov no tau lees paub los ntawm lawv cov qauv zoo sib xws rau chloroplasts, uas yog lub xub ntiag ntawm cov tshuaj tiv thaiv cov chaw thiab lub teeb teeb pom kev zoo, nrog rau cov txiaj ntsig dav dav ntawm photosynthesis, ua rau tsim cov organic tebchaw. Nws yuav tsum raug sau tseg tias cov nroj tsuag qis - ntsuab algae, zoo li prokaryotes, tsis muaj plastids. Qhov no yog vim qhov tseeb tias chlorophyll-muaj formations - chromatophores, tau coj lawv txoj haujlwm - photosynthesis.
How chloroplasts originated
Nrog ntau qhov kev xavkeeb kwm ntawm plastids, cia peb nyob ntawm symbiogenesis. Raws li nws cov tswv yim, plastids yog cov hlwb (chloroplasts) uas tau tshwm sim hauv Archean era los ntawm kev nkag mus ntawm cov kab mob phototrophic mus rau hauv thawj heterotrophic cell. Nws yog lawv uas tom qab ntawd coj mus rau kev tsim cov plastids ntsuab.
Nyob rau hauv kab lus no, peb kawm txog cov qauv thiab kev ua haujlwm ntawm ob-membrane organelles ntawm cov nroj tsuag: leukoplasts, chloroplasts thiab chromoplasts. Thiab kuj pom lawv qhov tseem ceeb hauv lub neej ntawm tes.
