HUJAYRAHOI PROKARIOTI

YAke az namoyandahoi hujayrahoi prokarioti bakteriyaho meboshand. Bakteriyaho dar hama joy – havo, ob, zamin, khurokvori, zeri khok, uqyonus, qullai kuhho, dar qari yakhhoi Arktiki va Antarktika, obhoi zerizaminii garm, qabati boloi atmosfera vomekhurand. Novobasta az sokhti sodda, bakteriyaho qobiliyati balandi mutobiqat dorand.

Bakteriyaho yake az shaklhoi soddai hayot buda, ba tipii mavjudoti zindai qadimi dokhil meshavand va dar ibtidoi avvali taraqqiyoti hayot dar rui zamin paydo shudaand.

Gumon meravad, ki nakhust bakteriyaho dar bahrho zindagi mekardand va mumkin az onho mikroorganizmhoi hozira paydo shudaand. Inson bo olami mikrobho faqat dar asri HVII shinosoi paydo kard, zero dar hamin davra zarrabin (linza) ikhtiro gardid va bo yorii on jismhoi ba chashm noayonro didan mumkin bud. Taraqqiyoti minbadai tekhnika dar asrhoi oyanda imkoniyat dod, ki bakteriyaho va digar organizmhoi prokariotiro hamatarafa omuzand. Agar ba khususiyati sokhti hujayrai bakteriyaho nigarem, gunogunshakli ba nazar merasad (rasmi. 5.1). Az jumla, andozai hujayrai bakteriyaho khele ham gunogun meboshand (az 1 to 10-15 mkm).

Vobasta ba shakl, onhoro hujayrahoi doirashakl, qoqi darozruya, chubchamonand, pechkhurda, spirali (rasmi 5.2) menomand.

Bakteriyaho vobasta ba namud tanho, bazeashon dar shakli tuda zindagi mekunand. Masalan, streptokkokho dar odam va hayvon bemorihoi iltihobiro ba vujud ovarda, dar shakli zanjir az chand hujayrahoi bakteriyavi tashakkul yoftaand; stafilakkokho ba rohi nafasi kudakon siroyat karda, dar shakli khushai angur inkishof meyoband.

Vobasta ba khususiyati fiziologi bakteriyaho gunogun meshavand. Onho metavonand dar holati aerobi (booksigen), anaerobi (beoksigen) va yo dar hardu holat hayot guzaronand. Manbai energiya baroi onho ravandhoi nafaskashi, turshonidan yo fotosintez mahsub meyoband. Bisyor namudi onho doroi pigmenthoi gunogun meboshand. Beshtari bakteriyaho dar organizmi hayvonot va rastaniho sukunat karda, onhoro ba bemoriho giriftor menamoyand. Vaqthoi okhir muqarrar gardid, ki baze bakteriyaho dar bakteriyahoi digar paraziti mekunand.

Bakteriyaho hasta (yadro) nadorand va akhbori irsi dar yak khromosoma joy gariftaast. Hromosomai bakteriya az yak malekulai KDN iborat buda, shakli halqaro dorad va dar sitoplazma joygir shudaast. KDN-i bakteriyaho majmuai safedahoro nadorad. Binobar in, beshtari hissachahoi irsi, yane genho, ki dar khromosomaho joygirand, dar holati faol qaror doshta, az onho payiham akhbori irsi nuskhabardor meshavad. Hujayrai bakteriyaho bo parda (membrana) ihota shudaast (rasmi 5.2), ki sitoplazmaro, az devori hujayra judo mekunad. Dar sitoplazma hissai membrana kam ast; dar on ribosomaho joy doshta, safedaro sintez mekunand.

Naqshai sokhti hujayrai prokariotho Hamai fermenthoe, ki dar rafti faoliyati bakteriyaho shirkat dorand, dar sitoplazma dar shakli diffuzi pare-

shon meboshand yo ba membranai daruni chaspidaand. Dar bisyor mikroorganizho moddahoi zakhiravi dar shakli poliangishtobho, charbho va polifosfatho dar daruni hujayra jam meoyand. In moddaho dar jarayoni mubodilai moddaho ba bakteriyaho dokhil shuda, dar mavridi nabudani energiyai beruni hayoti onhoro tamin mesozand.

Afzoishi bakteriyaho bo rohi taqsimshavi ast. Taqsimshavi badi duchand gashtani khromosomai halqagi va daroz shudani hujayra ogoz yofta, tadrijan pardai mobayni va sipas, hujayrahoi dukhtari tashakkul meyoband.

Bazan bakteriyaho bo rohi jinsi meafzoyand va dar natija omezish (kombinatsiya)-i navi genho dar khromosomai bakteriyaho ba vujud meoyand. Aksari bakteriyaho spora meofarand. Sporaho hamon vaqt paydo meshavand, ki agar zakhi-

rai moddahoi gizoi kam gardad yo dar muhiti zist miqdori mahsuli mubodila az meyor ziyod ast.

Tashakkuli spora dar shakli tanobak dar qismi sitoplazmai hujayrai modari ogoz yofta, on bo membrana ihota shudaast.

Badan spora bo pardai hujayravi ihota meshavad. Goho in parda serqabat meboshad. Hamin tavr, jarayoni faoliyati hayot dar spora qat megardad. Sporai bakteriyaho dar holati khushki khele ustuvorand.

 Dar in mavridho spora qobiliyati hayotii khudro sadho va hazorho sol nigoh doshta, garmovu sarmoro az sar meguzaronad. Ba in guftaho sporahoe, ki az qabrhoi kuhna yoft shudaand, shahodat medihand (mu-miyoi qadimai misriho, zakhirai mahsuloti khuroki dar gorho). CHunin sporaho, agar dar sharoiti musoid joy yoband, ba hujayrahoi bakteriyahoi faol mubaddal megardand.

Olimon mikroorganizmhoro az sporahoi yakhbastai 10-12 hazor sola parvarish kardaand.

Hamin tavr, hosilshavii spora dar prokariotho yake az zinahoi hayot buda, sharoiti noguvori muhiti berunaro az sar meguzaronad. Fayr az in, holati sporagi imkon medihad, ki onho ba vositai bod va omilhoi digar pahn shavand.

Savolho baroi sanjish:

1. Organoidhoi hujayraro nombar kuned.
2. Dar kadom asos hamai organizmhoi zindaro ba du guruh, yane prokariotho va eukariotho judo mekunand?
3. Kadom organizmho ba prokariotho dokhil meshavand?
4. Sokhti hujayrai bakteriyaro sharh dihed.
5. Bateriyaho chi guna afzoish meyoband?
6. Muhiti sporahosilshavii bakteriyaho dar chist?

Istilohot:

1. Mezosoma – qismi berunai membranai sitoplazma.
2. Mikoplazmaho – shakli nisbatan soddai namoyandai pro- kariotho, ki pardai hujayraro nadorand.
3. Sporahosilshavi – zinai hayoti prokariotho, ki bo nomusoidii muhit vobasta ast.
4. Sianobakteriyaho – organizmhoi prokariotii qobili fotosintez, ki dar bazei onho majmuai pigmentii ba rastanihoi darajai oli khos vujud dorad.
5. Arkheobakteriya – prokariothoe, ki khususiyathoi qadimai khudro nigoh doshtand.
6. Hromosomai halqagi – mavodi irsii hujayrahoi prokarioti, ki KDN dar shakli molekulai halqagi mavjud ast.