Waklanyelwa Ukuphila Phakade

UMZIMBA womuntu uklanywe ngendlela emangalisayo. Ukwakheka nokukhula kwawo kumane nje kuyisimangaliso. Umlobi wasendulo wababaza: “Ngenziwa ngokwesabekayo nangokumangalisayo.” (IHubo 139:14) Bekuqaphela ngokugcwele ukumangalisa komzimba womuntu, abanye ososayensi banamuhla bakuthola kudida ukuguga nokufa. Ingabe wena ukuthola kunjalo?

Isazi sezinto eziphilayo saseHarvard University uSteven Austad sabhala: “Sibhekana nokuguga njalo kangangokuthi ngiyamangala ukuthi abantu abaningi abakubheki njengemfihlakalo eyinhloko yezinto eziphilayo.” U-Austad waphawula ukuthi iqiniso lokuthi wonke umuntu uyaguga “lenza [ukuguga] kubonakale kungadidi kakhulu.” Nakuba kunjalo, lapho ucabangisisa ngempela, ingabe ukuguga nokufa kunengqondo?

Ngonyaka odlule, encwadini yakhe ethi How and Why We Age, uDkt. Leonard Hayflick waphawula ngokumangalisa kokuphila komuntu nokukhula kwakhe wayesebhala: “Ngemva kokwenza izimangaliso ezisisusa ekukhulelweni kuya ekuzalweni bese kudlulela ekuvuthweni ngokobulili nasebudaleni, imvelo yakhetha ukungaklami okwakuyobonakala kuyindlela eyisisekelo yokulondoloza lezo zimangaliso phakade. Sekungamashumi eminyaka ukuqonda lokhu kudida izazi zesayensi yokuguga.”

Ingabe nawe kuyakudida ukuguga nokufa? Kufeza yiphi injongo? UHayflick waphawula: “Cishe zonke izenzakalo zokuphila kusukela ekukhulelweni kuya ekuvuthweni zibonakala zinenjongo, kodwa ukuguga akunayo. Akuqondakali ukuthi kungani kufanele kube khona ukuguga. Nakuba siye safunda okuningi ngesayensi yokuguga . . . , sisasele nomphumela ongenakugwenywa wokuguga okungenanjongo okulandelwa ukufa.”

Kungenzeka yini ukuthi sasidalelwe ukuba singagugi bese siyafa kodwa ukuba siphile phakade emhlabeni?

Isifiso Sokuphila

Ngokuqinisekile uyaqaphela ukuthi cishe wonke umuntu uyakuzonda ukuguga nokufa. Eqinisweni, abaningi bayesaba ukubhekana nakho. Encwadini yakhe ethi How We Die, udokotela uSherwin B. Nuland wabhala: “Akekho kithi obonakala ekwazi ngokwengqondo ukubhekana nomcabango wesimo sethu sokufa, umqondo wokungazi lutho unomphela okungenanjongo—okungekho lutho noluncane kuwo.” Ukhona yini omaziyo ofuna ukuguga, agule, abese efa?

Nokho, ukuba ukuguga nokufa bekungokwemvelo futhi kuyingxenye yepulani elawulayo, besingeke yini sikwamukele? Kodwa asikwamukeli. Ngani? Impendulo itholakala endleleni esenziwa ngayo. IBhayibheli lithi: “[UNkulunkulu] ufake ngisho nobuphakade ezingqondweni [zethu].” (UmShumayeli 3:11, Byington) Ngenxa yalesi sifiso sokuba nekusasa elingenakuphela, sekuyisikhathi eside abantu befuna lokho okubizwa ngokuthi umthombo wobusha. Bafuna ukuhlala bebasha phakade. Lokhu kuphakamisa umbuzo, Kungenzeka yini siphile isikhathi eside?

Waklanyelwa Ukuba Uzivuselele

Sibhala kumagazini i-Natural History, isazi sezinto eziphilayo u-Austad saveza umbono ovamile: “Sithambekele ekucabangeni ngathi nezinye izilwane ngendlela esicabanga ngayo ngemishini: ukuguga kumane nje akunakugwenywa.” Kodwa lokhu akulona iqiniso. U-Austad wathi: “Izinto eziphilayo zihluke ngokuphelele emishinini. Ziyazivuselela: izilonda ziyaphola, amathambo ayahlangana, ukugula kuyadlula.”

Ngakho, kuphakama umbuzo othakazelisayo, Kungani siguga? Njengoba u-Austad abuza: “Kungani-ke [izinto eziphilayo] kufanele zibhekane nokuguga okufanayo nokwemishini?” Njengoba izicubu zomzimba zizivuselela, bezingenakuqhubeka yini zenza kanjalo phakade?

Kumagazini i-Discover, isazi sokuziphendukela kwemvelo kwezinto eziphilayo uJared Diamond saxoxa ngekhono elimangalisayo lokuzivuselela kwezinto eziphilayo. Sabhala: “Isibonelo esisobala kakhulu sokulawula ukulimala esisebenza emizimbeni yethu ukuphola kwezilonda, okulungisa ukulimala kwesikhumba sethu. Izilwane eziningi zingafinyelela imiphumela ephawuleka kakhulu kunathi: izibankwa zingayivuselela imisila enqamukile, ama-starfish nezinkalankala zingazivuselela izitho zomzimba, ama-sea cucumber angawavuselela amathumbu awo.”

Ngokuphathelene nokuvuselelwa kwamazinyo, uDiamond wathi: “Abantu baba namasethi amabili, izindlovu amasethi ayisithupha, kanti oshaka isibalo esingenakubalwa phakathi nesikhathi sabo sokuphila.” Khona-ke wachaza: “Ukuzivuselela njalo kwenzeka ngisho nangezinga elingabonakali emehlweni omuntu. Sivuselela amangqamuzana asemathunjini ethu njalo ngemva kwezinsuku ezimbalwa, lawo amboze isinye njalo ngemva kwezinyanga ezimbili, namangqamuzana egazi abomvu njalo ngemva kwezinyanga ezine.

“Emangqamuzaneni ethu ama-molecule amaprotheni ashintsha njalo ngezinga elivame kuyiprotheni ngayinye ngokukhethekile; kanjalo sigwema ukunqwabelana kwama-molecule alimele. Ngakho uma uqhathanisa ukubukeka kothandiweyo wakho namuhla nalokho kwangenyanga edlule, kungase kubukeke kufana, kodwa iningi lama-molecule ngamanye akha lowo mzimba wothandekayo lihlukile.”

Amangqamuzana amaningi omzimba athathelwa indawo njalo amanye amasha. Kodwa amanye amangqamuzana, njengamangqamuzana ezinzwa obuchopho, angase angavuseleleki. Nokho, uHayflick wachaza: “Uma ingqamuzana iye yavuselelwa zonke izingxenye zayo akuseyona leya ngqamuzana endala. Amangqamuzana ezinzwa owazalwa nawo angase namuhla abukeke kusengamangqamuzana afanayo, kodwa empeleni ama-molecule amaningi awakha lapho uzalwa . . . kungenzeka asevuselelwe ngama-molecule amasha. Ngakho-ke amangqamuzana angakhuli kungenzeka akuwona amangqamuzana afanayo owazalwa unawo!” Lokhu kungenxa yokuthi izakhi zamangqamuzana ziyavuselelwa. Ngakho, kucatshangwa ukuthi ukuvuselelwa kwezinto ezisemzimbeni bekungasigcina siphila phakade!

Khumbula ukuthi uDkt. Hayflick wakhuluma ‘ngezimangaliso ezisisusa ekukhulelweni kuya ekuzalweni.’ Yiziphi ezinye zalezi? Njengoba sizihlola kafushane, cabangela ithuba lokusetshenziswa kwalokho akubiza ngokuthi ‘indlela eyisisekelo yokulondoloza lezo zimangaliso phakade.’

Ingqamuzana

Umuntu omdala unamangqamuzana angaba izigidi eziyizigidi eziyikhulu, ngayinye eyinkimbinkimbi ngendlela engachazeki. Ukuze ubonise lobu bunkimbinkimbi, umagazini i-Newsweek waqhathanisa ingqamuzana nedolobha elibiyelwe. Lomagazini wathi: “Izikhungo zamandla zikhiqiza amandla engqamuzana. Amafektri akhiqiza amaprotheni, izingxenye ezibalulekile zohwebo lwamakhemikhali. Izimiso zokuthutha eziyinkimbinkimbi ziqondisa amakhemikhali athile kusuka kwenye indawo kuya kwenye ngaphakathi kwengqamuzana nangaphandle. Amasosha avimbe emgwaqweni alawula izimakethe zokukhipha nokungenisa impahla edolobheni, futhi abeke iso endaweni engaphandle ebheke izimpawu zengozi. Amabutho aqeqeshiwe ahlala emi ngomumo ukuze alwe nabahlaseli. Uhulumeni ophethe wezakhi zofuzo ugcina ukuhleleka.”

Cabangela indlela wena—amangqamuzana akho angaba izigidi eziyizigidi eziyikhulu—owavela ngayo. Waqala uyingqamuzana eyodwa eyakheka lapho isidoda sikayihlo sihlangana neqanda likanyoko. Kulokhu kuhlangana, kwadwetshwa amapulani kuyi-DNA (isifushaniso selithi deoxyribonucleic acid) aleyo ngqamuzana eyayisanda kwakhiwa ukuze kuvele lokho ekugcineni okwaba nguwe—umuntu omusha shá nohlukile. Kuthiwa uma imiyalo ekuyi-DNA “ingabhalwa phansi, ibingagcwalisa izincwadi eziyinkulungwane ezinamakhasi angu-600.”

Ngokuhamba kwesikhathi, leyo ngqamuzana yokuqala yaqala ukukhula, iba amangqamuzana amabili, kwase kuba amane, angu-8, njalonjalo. Ekugcineni, ngemva kwezinsuku ezingaba ngu-270—okuyisikhathi lapho kwase kwakheke izinkulungwane zezigidi zamangqamuzana ahlukahlukene ngaphakathi kunyoko ukuze kwakheke umntwana—WENA wazalwa. Kunjengokungathi leyo ngqamuzana yokuqala yayinekamelo elikhulu eligcwele izincwadi ezinemiyalo eningiliziwe yendlela yokukwenza. Kodwa okumangalisayo futhi iqiniso lokuthi lemiyalo eyinkimbinkimbi yadluliselwa engqamuzaneni ngayinye eyalandela. Yebo, ngokumangalisayo, ukuthi ingqamuzana ngayinye emzimbeni wakho inakho konke ukwaziswa okufanayo okwakuqukethwe iqanda lokuqala elavundiswa!

Cabangela nalokhu. Njengoba ingqamuzana ngayinye inokwaziswa kokukhiqiza zonke izinhlobo zamangqamuzana, lapho kufika isikhathi, ake sithi sokwenza amangqamuzana enhliziyo, yanqandwa kanjani imiyalo yokwenza onke amanye amangqamuzana? Kubonakala sengathi isebenza njengomakhi oneqoqo eliphelele lamapulani okwenza umntwana, ingqamuzana ethile yakhetha kuleli qoqo layo ipulani yokwenza amangqamuzana enhliziyo. Enye ingqamuzana yakhetha ipulani ehlukile enemiyalo yokukhiqiza amangqamuzana ezinzwa, kanti enye yathatha ipulani yokwenza amangqamuzana esibindi, njalonjalo. Ngokuqinisekile, leli khono elingakachazwa lengqamuzana lokukhetha imiyalo edingekayo ukuze ikhiqize uhlobo oluthile lwengqamuzana futhi ngesikhathi esifanayo inqande yonke eminye imiyalo kungesinye ‘sezimangaliso eziningi ezisisusa ekukhulelweni kuya ekuzalweni.’

Nokho, kunokuningi okwengeziwe. Ngokwesibonelo, amangqamuzana enhliziyo kudingeka ashukunyiswe ukuze afingqeke ngokuvumelana. Ngakho, enhliziyweni kwakhiwa isimiso esiyinkimbinkimbi sokuphehla amaza ezinzwa abangela inhliziyo ukuba ishaye ngendlela efanele ukuze isekele umzimba emsebenzini owenzayo. Ngempela, umklamo oyisimangaliso! Yingakho odokotela beye bathi ngenhliziyo: “Iphumelela kakhulu kunanoma iluphi uhlobo lomshini owake waklanywa umuntu.”

Ubuchopho

Isimangaliso esikhulu nakakhulu ukwakheka kobuchopho—ingxenye exaka kakhulu yesimangaliso esiwumuntu. Ngemva kwamasonto amathathu okukhulelwa, amangqamuzana obuchopho ayaqala ukwakheka. Ekugcineni, kufakwa amangqamuzana ezinzwa angaba izigidi ezingu-100 000—amaningi ngangezinkanyezi zeMilky Way—ebuchosheni bomuntu.

“Ngayinye yawo ithola ukwaziswa okuvela kwamanye amangqamuzana ezinzwa angaba ngu-10 000 ebuchosheni,” kubika umagazini i-Time, “bese ithumela imiyalezo kwamanye ayinkulungwane.” Ephawula amathuba okuhlangana angase avele, usosayensi wezinzwa uGerald Edelman wathi: “Ingxenye yobuchopho engangesihloko sothi lukamentshisi inamalunga angaba izigidi eziyinkulungwane angahlangana ngezindlela ezingachazwa kuphela ngokuthi ziyisimangaliso esikhulukazi—ngohlelo lweshumi elilandelwa izigidi zamaqanda [zero].”

Lokhu kunikeza ubuchopho liphi ikhono? Isazi sezinkanyezi uCarl Sagan sathi ubuchopho bomuntu bungagcina ukwaziswa “okungagcwalisa imiqulu engaba izigidi ezingamashumi amabili, eminingi njengetholakala emitatsheni yezincwadi emikhulu emhlabeni.” Umlobi uGeorge Leonard wanezela, ebabaza: “Eqinisweni, mhlawumbe sesingahlongoza umbono omangalisayo: Kungenzeka ikhono eliphakeme lobuchopho lokusungula izinto cishe alinamkhawulo.”

Ngakho, amazwi alandelayo akufanele asimangalise: “Ubuchopho,” kusho isazi samangqamuzana ezinto eziphilayo uJames Watson, ongomunye wabathola ukwakheka kwe-DNA, “buyinto eyinkimbinkimbi kunazo zonke esake sazithola kuyo yonke indawo yethu.” Isazi sezinzwa uRichard Restak, esingakuthandi ukuqhathaniswa kobuchopho ne-computer, sathi: “Ubungqayizivele bobuchopho bubangelwa iqiniso lokuthi ayikho neyodwa into kuyo yonke indawo eyaziwayo efana ngisho nokufana nabo.”

Ngokokunye ukulinganisela, ososayensi bezinzwa bathi phakathi nesikhathi sethu sokuphila samanje, sisebenzisa ingxenye encane kakhulu yamandla ethu obuchopho, cishe u-1/10 000, noma u-1/100 wephesenti elilodwa kuphela. Ake ucabange ngakho. Ingabe kunengqondo ukuthi sasinganikezwa ubuchopho obunamandla amangalisa kangaka ukuba babungenakusetshenziswa ngokugcwele? Ingabe akunangqondo ukuthi abantu, abanekhono lokufunda bengaphezi, eqinisweni babeklanyelwe ukuphila phakade?

Uma lokho kuyiqiniso, kungani siguga? Konakalaphi? Kungani, ngemva kweminyaka engaba ngu-70 noma engu-80, sifa, nakuba ngokusobala imizimba yethu yaklanyelwa ukuba ihlale phakade?

[Umdwebo ekhasini 7]

(Ukuze ubone ukuthi indaba ihlelwe kanjani, bheka encwadini)

Ingqamuzana—Umklamo Oyisimangaliso

Ulwelwesi Lwengqamuzana:

Isembozo esilawula okungenayo nokuphumayo engqamuzaneni

I-nucleus:

Njengoba ivalelwe esembozweni esinolwelwesi olukabili, iyisikhungo esilawula okwenziwa ingqamuzana

Ama-ribosome:

Izinto lapho ama-amino acid ehlanganiswa khona enziwe amaprotheni

Ama-chromosome:

Aqukethe i-DNA yengqamuzana, ipulani elawulayo yezakhi zofuzo

I-nucleolus:

Indawo okuhlanganiswa kuyo ama-ribosome

I-endoplasmic reticulum:

Izingcwecwe zolwelwesi ezigcina noma zithuthe amaprotheni enziwa ama-ribosome anamathele kuzo (amanye ama-ribosome antanta ngokukhululekile engqamuzaneni)

Ama-mitochondrion:

Izikhungo ezikhiqiza i-ATP, ama-molecule anikeza ingqamuzana amandla

I-golgi body:

Iqembu lezikhwama zolwelwesi eziyisicaba ezithwala futhi sisakaze amaprotheni enziwe ingqamuzana

Ama-centriole:

Ahlala eduze ne-nucleus futhi awusizo ekukhuleni kwengqamuzana