Wawuyilelwe Ukuphila Ngonaphakade
UMZIMBA womntu uyilwe ngokumangalisayo. Ukukhula kwawo kungummangaliso. Umbhali wamandulo wathi: “Ndenziwe ngokoyikekayo.” (INdumiso 139:14) Nangona zikwazi kakuhle ukumangalisa komzimba womntu, zimbi izazinzulu zanamhlanje ukwaluphala nokufa kuzishiya zime nematha. Ngaba nawe unjalo?
Isazinzulu ngebhayoloji saseHarvard University uSteven Austad, sabhala: “Ukwaluphala, yeyona nto sisoloko sijamelana nayo kangangokuba iyamangalisa into yokuba abantu abaninzi bengakujongi njengemfihlelo ephambili engokwebhayoloji.” Isibakala sokuba wonke ubani esaluphala, lo kaAustad wathi, “senza [ukwaluphala] kubonakale kungaxhomisi mehlo kangako.” Sekunjalo, xa ucingisisa ngako, ngaba ukwaluphala nokufa kuyinto esengqiqweni?
Kunyaka ophelileyo, kwincwadi yakhe ethi How and Why We Age, uGqr. Leonard Hayflick wakuvuma ukumangalisa kobomi bomntu nokukhula kwakhe waza wabhala: “Emva kokuba yenze imimangaliso ukususela ekukhawulweni ise ekuzalweni kwethu nasekukhuleni kwethu ngokwesini size sibe ngabantu abakhulu, indalo iyoyiswa kukwenza eyona nkqubo ibonakala ilula ukugcina loo mimangaliso iqhubeka ngonaphakade. Le ndlela yokuqiqa ishiye ii-biogerontologist [abo bafundisisa ngebhayoloji ephathelele ukwaluphala] zime nematha kangangamashumi eminyaka.”
Ngaba nawe ukwaluphala nokufa kukushiya ume nematha? Yintoni injongo yako? Lo kaHayflick wathi: “Phantse zonke izinto ezingokwebhayoloji ezenzeka ukususela ekukhawulweni ukusa ebuntwini obukhulu zibonakala zinenjongo, kodwa ukwaluphala akubonakali kunenjongo. Asicacanga isizathu sokuba ukwaluphala kufanele kubekho. Nangona siye safunda okungakumbi ngebhayoloji yokwaluphala . . . , sisamhokamhokana nemiphumo engathintelekiyo yokwaluphala okungenanjongo okwandulela ukufa.”
Ngaba kunokwenzeka bethu ukuba sasingadalelwanga ukuba saluphale size sife kodwa sasidalelwe ukuphila ngonaphakade emhlabeni?
Umnqweno Wokuphila
Ngokuqinisekileyo uyaqonda ukuba wonk’ ubani ukuthiyile ukwaluphala nokufa. Enyanisweni, abaninzi bayakoyika. Kwincwadi yakhe ethi How We Die, ugqirha wezonyango uSherwin B. Nuland wabhala: “Ngokusengqiqweni akukho namnye kuthi obonakala enako ukuyicinga ngengqondo yakhe imeko yethu yokufa, apho singayi kuba sezingqondweni ngokupheleleyo kwampengempenge apho kukhal’ ibhungane—apho kungekho nto kwaphela.” Ngaba kukho uthile omaziyo ofuna ukwaluphala, agule, aze afe?
Kanti, ukuba ukwaluphala nokufa bekungokwemvelo yaye kuyinxalenye yokubunjwa kwethu, ngaba besingenakukwamkela? Kodwa asikwamkeli. Kutheni singakwamkeli nje? Impendulo ifumaneka kwindlela esenziwa ngayo. IBhayibhile ithi: “[UThixo] ufake ubunaphakade ezingqondweni [zethu].” (INtshumayeli 3:11, Byington) Ngenxa yoku kunqwenela ikamva elihlala lihleli, abantu bebephum’ iphulo befuna izinto ekufane kuthiwe ziya kubagcina bebatsha. Bafuna ukuhlala bebatsha ngonaphakade. Oku kuphakamisa lo mbuzo, Ngaba singakwazi ukuphila ngonaphakade?
Ziyilelwe Ukuba Zizilungise
Sibhala kwiphephancwadi iNatural History, isazinzulu ngebhayoloji uAustad saveza le mbono iqhelekileyo: “Sinomkhwa wokucinga ngathi nezinye izilwanyana ngendlela esicinga ngayo ngoomatshini: ukuwohloka akunakuthintelwa.” Kodwa oku akuyonyaniso. Lo ka-Austad wathi: “Ngokusisiseko izinto eziphilayo ezingokwebhayoloji zahlukile koomatshini. Ziyazilungisa: ziphilisa amanxeba, zimilisa amathambo, ziphelisa izigulo.”
Ngaloo ndlela, nanku umbuzo obangel’ umdla, Kutheni sisaluphala nje? Njengoko oka-Austad wabuzayo: “Ngoko, kutheni [izinto eziphilayo ezingokwebhayoloji] ziwohloka njengoomatshini?” Ekubeni izicwili zomzimba zizilungisa ngokwazo, ngaba bezingena kwenza oko ngonaphakade?
Kwiphephancwadi iDiscover, isazinzulu ngebhayoloji esikholelwa kwindaleko uJared Diamond saxubusha ngamandla amangalisayo okukwazi ukuzilungisa kwezinto eziphilayo. Wabhala: “Owona mzekelo ubonakala kakuhle wokulungiswa komonakalo emizimbeni yethu kukuphiliswa kwamanxeba, apho kuthi kulungiswe umonakalo kwisikhumba sethu. Kwizilwanyana kwenzeka izinto ezinkulu kunezo zenzeka kuthi: imisila yamacilikishe eqhawukileyo iphinda ikhule, i-starfish noononkala banokulungisa amalungu abo, ii-sea cucumber zinokulungisa amathumbu azo.”
Ngokuphathelele ukubuyiselwa kwamazinyo, lo kaDiamond wathi: “Ebantwini kukhula iiseti ezimbini, ezintandathu kwiindlovu ibe kookrebe akhula de bayokufa.” Wandula wachaza: “Kukho nezinto ezingabonakaliyo ezibuyiselwa ngokuthe rhoqo. Iiseli eziphakathi kwinwebu yamathumbu ethu zibuyiselwa kanye emva kweentsuku ezimbalwa, ezikwisinyi kanye emva kweenyanga ezimbini neeseli zegazi ezibomvu kanye emva kweenyanga ezine.
“Ngokuphathelele iiseli zomntu iimolekyuli zethu zeproteni ziguquguquka ngomlinganiselo owahlukileyo kwiproteni nganye; ngaloo ndlela iimolekyuli ezonakeleyo azifumbi. Ngenxa yoko ukuba uthelekisa inkangeleko yanamhlanje yomntu omthandayo naleyo yenyanga ebingaphambi kwaleyo, usenokukhangeleka ngendlela efanayo, kodwa iimolekyuli ezininzi ezibumba loo mzimba uthandekayo zahlukile.”
Iiseli zomzimba ezininzi zithatyathelwa indawo zezintsha ngamaxesha athile. Kodwa ezinye iiseli, njengeeseli zengqondo, azinakuze zithatyathelwe indawo zezinye. Noko ke, okaHayflick wachaza: “Ukuba zonke iinxalenye zeseli ziye zathatyathelwa indawo ayiseyiyo laa seli indala. Iiseli zengqondo owazalwa unazo zisenokubonakala namhlanje zingatshintshanga, kodwa enyanisweni iimolekyuli ezininzi ezazibumba ezo seli ekuzalweni kwakho . . . zisenokuba zathatyathelwa indawo ziimolekyuli ezintsha. Ngoko iiseli ezingahlulahlulekiyo zisenokungabi ziiseli owazalwa nazo ngapha koko!” Oku kungenxa yokuba izinto ezibunjwe ngazo ezo seli zathatyathelwa indawo. Ngaloo ndlela, ukuthatyathelwa indawo kwezinto zomzimba ezifunekayo kucingelwa ukuba kunokusigcina siphila ngonaphakade!
Khumbula ukuba uGqr. Hayflick wathetha “ngemimangaliso ukususela ekukhawulweni ukusa ekuzalweni kwethu.” Yiyiphi eminye yayo? Njengoko siyihlolisisa ngokufutshane, khawucinge ngoko kunokwenzeka xa kuphunyezwa oko wakubiza ngokuba “yinkqubo elula yokugcina loo mimangaliso iqhubeka ngonaphakade.”
Iseli
Umntu omdala ubunjwa ziiseli ezimalunga ne-100 lezigidi zezigidi, nganye kuzo intsonkothe ngendlela engenakuqondwa. Lizekelisa ngoku kuntsonkotha kweseli, iphephancwadi iNewsweek layifanisa nesixeko esibiyelwe ngodonga. Eli phephancwadi lathi: “Izikhululo zombane ziphehla amandla eseli. Imizi-mveliso ivelisa iiproteni, imichiza efunekayo. Izithuthi zithutha imichiza ziyisuse kwindawo ethile ziyise kwenye ngaphakathi nangaphandle kwiseli. Abalindi abangxange emideni bahlola izinto eziphumayo nezingenayo, baze babek’ iliso kwizinto ezinokuba yingozi. Imikhosi eqeqeshiweyo ezizinto ezingokwebhayoloji ihlala ilungele ukuqubisana nabahlaseli. Urhulumente oyimizila yemfuza ugcine ucwangco.”
Khawuqwalasele indlela wena—iiseli zakho ezimalunga ne-100 lezigidi zezigidi—owabakho ngayo. Waqala njengeseli enye eyenzeka xa idlozi elisuka kuyihlo lathi ladibana neqanda elisuka kunyoko. Koko kudibana, kwazotywa iiplani kwi-DNA (isishunqulelo sika-deoxyribonucleic acid) zaloo seli esandul’ ukwenziwa ukuze ivelise oko kwathi kwaba nguwe ekugqibeleni—umntu omtsha nowahluke ngokupheleleyo. Kuthiwa, imiyalelo ye-DNA, “ukuba ibinokubhalwa, ibinokuzalisa iwaka leencwadi ezinamaphepha angama-600.”
Ekuhambeni kwexesha, loo seli yokuqala iqalisa ukwahlukana, yenze iiseli ezimbini, zandule ke zibe ne, zibe sibhozo, njalo njalo. Ekugqibeleni, malunga neentsuku ezingama-270—ebudeni bexesha laxa amawaka ezigidi zeeseli eziziintlobo ezininzi ezahlukahlukeneyo ziye zakhula kunyoko ukuze zenze usana—kwazalwa WENA. Ngokungathi kunjalo iseli yokuqala yayinegumbi elikhulu leencwadi ezinemiyalelo eneenkcukacha ngendlela yokwenza wena. Kodwa okona kumangalisayo sisibakala sokuba le miyalelo intsonkothileyo yayidluliselwa kwiseli nganye elandelayo. Ewe, okumangalisayo kukuba, iseli nganye emzimbeni wakho inayo yonke laa nkcazelo yayikwelaa qanda lokuqala laliqanduselwa!
Kwakhona khawucinge ngoku. Ekubeni iseli nganye inenkcazelo yokuvelisa zonke iintlobo zeeseli, ngokomzekelo, xa kwafika ixesha lokwenza iiseli zentliziyo, yathintelwa njani imiyalelo yokwenza ezinye iiseli? Kuyacaca ukuba, isebenza njengomakhi onekhabhathi eneeplani ezipheleleyo zokwenza umntwana, iseli ethile yakhetha iplani yokwenza iiseli zentliziyo kwifayile yayo esekhabhathini. Enye iseli yakhetha iplani eyahlukileyo enemiyalelo yokuveza iiseli zemithambo-luvo, kanti enye yathabatha iplani yokwenza iiseli zesibindi, njalo njalo. Ngokuqinisekileyo, obu buchule beseli bungekabi nakuchazwa bokukhetha imiyalelo efunekayo ukuze ivelise uhlobo oluthile lweseli ize kwangaxeshanye, ithintele yonke eminye imiyalelo ngomnye “wemimangaliso emininzi esusela ekukhawulweni ise ekuzalweni kwethu.”
Kanti, akuphelelanga apho. Ngokomzekelo, iiseli zentliziyo zifuna ukuvuselelwa ukuze zirhwaqele ngexesha elifanelekileyo. Ngaloo ndlela, entliziyweni kwakhiwa inkqubo entsonkothileyo yokukhupha amandla ombane ukwenzela ukuba intliziyo ibethe ngesantya esifanelekileyo ukuxhasa umzimba kumsebenzi owenzayo. Lo ngummangaliso wokwenene! Akumangalisi ukuba oogqirha baye bathi ngentliziyo: “Inobuchule ngaphezu kwawo nawuphi na umatshini oyilwe ngumntu.”
Ubuchopho
Okona kumangalisa kakhulu kukukhula kobuchopho—eyona ndawo iyimfihlelo kummangaliso womntu. Kwiiveki ezintathu emva kokukhawula, iiseli zobuchopho ziyaqalisa ukwakheka. Ekugqibeleni, malunga ne-100 000 ezigidi zeeseli zemithambo-luvo, ezibizwa ngokuba ziineurons—ezininzi njengeenkwenkwezi kumnyele oyiMilky Way—zakha ubuchopho bomntu.
Iphephancwadi iTime lanikela le ngxelo: “Nganye kwezi ifumana inkcazelo esuka kwezinye ii-neurons ezisebuchotsheni ezimalunga ne-10 000, ize ithumele imiyalelo kwezinye eziliwaka.” Sithetha ngezinto ezinokudibana, isazinzulu ngemithambo-luvo uGerald Edelman sathi: “Inxalenye ethile yobuchopho engangentloko yomcinga womatshisi iqulethe malunga newaka lezigidi obuxhakaxhaka obunokudibana ngendlela enokuchazwa kuphela njengengaphaya kommandla wendalo—zilandelelana ngokwamashumi alandelwa zizigidi zoonothi.”
Oku kwenza ubuchopho bube namandla angakanani? Isazi ngeenkwenkwezi uCarl Sagan sathi ubuchopho bomntu bunokuthwala inkcazelo “enokuzalisa imiqulu ezizigidi ezingamashumi amabini, elingana nekwawona mathala makhulu ehlabathini.” Umbhali uGeorge Leonard wahlabela mgama, wenjenje: “Enyanisweni, mhlawumbi ngoku singeza nale ngcamango ekunzima ukuyikholelwa: Amandla okuyila obuchopho aphantse abe akapheli.”
Ngaloo ndlela, asifanele sothuswe ngala magqabaza alandelayo: “Ubuchopho,” ngokutsho kwesinye isazinzulu ngebhayoloji yemolekyuli uJames Watson, esafumanisa i-DNA, “buyeyona nto intsonkothileyo esisayifumeneyo kummandla wethu wendalo.” URichard Restak isazi ngezifo zemithambo-luvo, okuthiyileyo ukufaniswa kobuchopho nekhompyutha, wathi: “Ubuchopho abunakuthelekiswa nanto kangangokuba akukho ndawo kummandla wendalo owaziwayo ekunokufunyanwa kuyo into enokufaniswa nabo.”
Izazinzulu ngemithambo-luvo zithi ebudeni bokuphila kwethu, sisebenzisa isixa nje esincinane samandla ethu engqondo, malunga ne-1/10 000, okanye i-1/100 kwisi-1 ekhulwini kuphela, ngokutsho kolunye uqikelelo. Khawufan’ ucinge. Ngaba kusengqiqweni ukuba sinikwe ubuchopho obunokwenza izinto ezingummangaliso olo hlobo ukuba kwakungafanelekanga busetyenziswe ngokupheleleyo? Ngaba akukho ngqiqweni ukuba abantu, abanomdla wokufunda ngokungenasiphelo, babe ngokwenene babeyilelwe ukuphila ngonaphakade?
Ukuba oko kuyinyaniso, kutheni sisaluphala? Konakele phi? Kutheni, emva kweminyaka engama-70 okanye engama-80, sisifa, kwanokuba kubonakala ukuba imizimba yethu yayiyilelwe ukuba ihlale ngonaphakade?
[Umzobo okwiphepha 7]
(Ukuba ufuna inkcazelo ehlahlelwe kakuhle, yiya kwimpapasho)
Iseli—Iyilwe Ngokungummangaliso
Cell Membrane:
Umaleko olawula izinto ezingenayo neziphumayo kwiseli
Nucleus:
Ikwinwebu ephindwe kabini, iliziko elalathisa izinto ezenzeka kwiseli
Ribosomes:
Indawo ezidityaniswa kuyo iiamino asidi ukuze zenze iiproteni
Chromosomes:
Zine-DNA yeseli, eyenza imizila yemfuza
Nucleolus:
Indawo ezidityaniswa kuyo ii-ribosome
Endoplasmic Reticulum:
Umaleko weenwebu ezigcina okanye ezihambisa iiproteni ezenziwe ziiribosome ezithe nca kuzo (ezinye ii-ribosome zihambahamba ngokukhululekileyo kwiseli)
Mitochondria:
Izazulu ezivelisa i-ATP, iimolekyuli ezinika iseli amandla
Golgi Body:
Iqela lezingxotyana zenwebu ezisibaca eziqokelela zize zihambise iiproteni ezenziwe yiseli
Centrioles:
Zisecaleni kwe-nucleus yaye ziluncedo ekukhuleni kweseli