Zitsanzo za Mafunso okhudza DNA ndi Majini
Pendauluan
Mu biology ya mamolekyulu, DNA (Deoxyribonucleic Acid) ndi majini ndi mfundo zazikulu zomwe zimayambira kumvetsetsa cholowa cha makhalidwe ndi magwiridwe antchito a zamoyo. DNA ndi molekyulu yomwe imasunga chidziwitso chonse cha majini chofunikira kuti chiwongolere kapangidwe ndi ntchito ya chamoyo. Koma majini ndi magawo a DNA omwe amalemba mapuloteni kapena RNA inayake. Kumvetsetsa DNA ndi majini ndikofunikira kwa aliyense amene ali ndi chidwi ndi sayansi ya zamoyo, sayansi ya zamoyo, mankhwala, ndi zina zotero. Nkhaniyi ikambirana mafunso ena omwe amafunsidwa kawirikawiri okhudzana ndi mitu iyi, pamodzi ndi mafotokozedwe awo.
1. Funso 1: Kapangidwe ka DNA
Funso: Fotokozani kapangidwe ka DNA ka double helix ndipo tchulani zigawo zazikulu zomwe zimapanga DNA.
Kukambirana: DNA ndi wiri helix, kutanthauza kuti imakhala ndi zingwe ziwiri zozungulirana, mofanana ndi masitepe ozungulira. Kapangidwe kameneka kanaperekedwa koyamba ndi James Watson ndi Francis Crick mu 1953, omwe adapambananso Mphoto ya Nobel chifukwa cha kupeza kwawo. DNA imapangidwa ndi zigawo zitatu zazikulu: phosphate, deoxyribose shuga, ndi maziko a nayitrogeni. Maziko a nayitrogeni awa ndi adenine (A), thymine (T), cytosine (C), ndi guanine (G). Mu wiri helix, maziko awa amaphatikizana makamaka: A awiriawiri okhala ndi T kudzera m'mabondo awiri a hydrogen, ndi C awiriawiri okhala ndi G kudzera m'mabondo atatu a hydrogen. Zingwe za makwerero a DNA zimayimiridwa ndi shuga ndi phosphate, pomwe makwerero amayimiridwa ndi mabondo awiri a base.
2. Funso 2: Kubwerezabwereza kwa DNA
Funso: Kodi tanthauzo la kubwerezabwereza kwa DNA m'njira ya semiconservative ndi chiyani, ndipo n'chifukwa chiyani kuli kofunikira?
Kukambirana: Kubwerezabwereza kwa DNA mu semiconservative ndi njira yomwe molekyulu iliyonse yatsopano ya DNA imakhala ndi chingwe chimodzi choyambirira ndi chingwe chimodzi chatsopano. DNA ikabwerezabwereza, helix iwiri imasweka ngati zipu, ndipo chingwe chilichonse choyambirira chimagwira ntchito ngati chitsanzo cha kapangidwe ka chingwe chatsopano. Njirayi ndi yofunika chifukwa imatsimikizira kuti selo lililonse la mwana wamkazi limalandira chingwe chimodzi cha DNA chomwe chili chofanana ndi chingwe choyambirira, kusunga umphumphu wa chidziwitso cha majini m'mibadwo yonse. Kubwerezabwereza kwa semiconservative kumathandiza kuchepetsa zolakwika panthawi yogawa maselo ndipo ndikofunikira kuti majini akhale ndi cholowa cholondola.
3. Funso 3: Kufotokozera za majini
Funso: Kodi njira zolembera ndi kumasulira zimachitika bwanji mu kufotokozera majini?
Kukambirana: Kufotokozera za majini kumaphatikizapo magawo awiri akuluakulu: kulemba ndi kumasulira. Mu kulemba, gawo la DNA lomwe lili ndi jini inayake limagwiritsidwa ntchito ngati chitsanzo chopangira messenger RNA (mRNA). Njirayi imachitika mu selo ndipo imaphatikizapo enzyme RNA polymerase, yomwe imagwirizana ndi DNA ndikusonkhanitsa mRNA kutengera DNA base sequence. Pambuyo polemba, mRNA imachoka mu selo ndikupita ku ribosomes mu cytoplasm, komwe kumasulira kumachitika.
Pakumasulira, ma ribosome amawerenga mndandanda wa mRNA m'magulu a ma codon atatu otchedwa ma codon. Kodoni iliyonse imakhala yapadera pa amino acid inayake. Kusamutsa RNA (tRNA) kumanyamula ma amino acid ofanana kupita ku ribosome, kenako nkuwasonkhanitsa mu unyolo wa polypeptide kutengera mndandanda wa codon. Unyolo wa polypeptide ukatha, umapititsidwa patsogolo kuti ukhale puloteni yogwira ntchito yomwe imagwira ntchito yofunika kwambiri mu selo.
4. Funso 4: Kusintha kwa majini
Funso: Kodi kusintha kwa majini kumatanthauza chiyani, ndipo kusintha kwa majini kungakhudze bwanji zamoyo?
Kukambirana: Kusintha kwa majini ndi kusintha kwa maziko a DNA. Kusintha kumeneku kungachitike mwadzidzidzi panthawi yobwerezabwereza kwa DNA kapena kuyambitsidwa ndi zinthu zakunja monga kuwala ndi mankhwala osinthika. Kusintha kwa majini kungakhudze zamoyo m'njira zosiyanasiyana, kutengera mtundu ndi malo a kusinthaku.
Masinthidwe amatha kugawidwa m'magulu atatu akuluakulu:
– Kusintha kwa mfundo: kumakhudza kusintha kwa nucleotide imodzi. Izi zitha kuchitika m'njira yosinthira (kusintha maziko amodzi ndi ena), kuyika, kapena kuchotsa.
– Kusintha kwa Missense: kumapangitsa kuti amino acid imodzi ilowe m'malo mwa puloteni.
– Kusintha kwa zinthu zopanda pake: kumapanga ma codon osatha msanga, kuletsa kupanga mapuloteni msanga.
– Kusintha kwa Frameshift: komwe kumachitika chifukwa cha kuyika kapena kuchotsera komwe kumasuntha chimango chowerengera mRNA.
Zotsatira za kusintha kwa majini zimatha kusiyana. Kusintha kwina sikukhudza (kusintha kwachete), pomwe kwina kumatha kusokoneza ntchito ya mapuloteni, kuyambitsa matenda a majini, kapena, nthawi zina, kumapereka mwayi wosintha zinthu.
5. Funso 5: Kugwiritsa ntchito Biotechnology ndi Recombinant DNA
Funso: Fotokozani momwe ukadaulo wa DNA wopangidwanso ungagwiritsidwire ntchito popanga mbewu zosagonjetsedwa ndi tizilombo.
Kukambirana: Ukadaulo wa DNA wophatikizana umaphatikizapo kuphatikiza majini ochokera ku zamoyo zosiyanasiyana kuti apange zamoyo zomwe zili ndi makhalidwe atsopano komanso ofunikira. Pakukula kwa mbewu zosagonjetsedwa ndi tizilombo, majini omwe amalemba mapuloteni omwe amapha tizilombo kapena kuletsa kukula kwawo amatha kutengedwa kuchokera ku mabakiteriya ndikuyikidwa mu genome ya zomera.
Mwachitsanzo, Bacillus thuringiensis (Bt) ndi bakiteriya yomwe imapanga puloteni yomwe ndi poizoni kwa tizilombo tina. Jini yomwe imapanga puloteni ya Bt imatha kuchotsedwa ndikuyikidwa mu DNA ya zomera pogwiritsa ntchito ukadaulo wa DNA wopangidwanso. Mbewu ya Bt yomwe imachokera imapanga puloteni yakeyake ndipo imatha kudziteteza ku tizilombo popanda kufunikira mankhwala ena ophera tizilombo. Izi sizimangowonjezera zokolola za mbewu komanso zimachepetsa kuwonongeka kwa chilengedwe chifukwa chogwiritsa ntchito mankhwala ophera tizilombo.
Kutseka
Kumvetsetsa DNA ndi majini sikofunikira kwa iwo omwe amagwira ntchito mu sayansi ya zamoyo ndi zamankhwala okha, komanso kwa anthu onse, chifukwa cha kufunika kwake pa sayansi ya zamoyo ndi miyoyo yathu ya tsiku ndi tsiku. Mwa kufufuza zitsanzo za mavuto ndi zokambirana, tikukhulupirira kuti izi zikupereka chidziwitso chakuya pankhaniyi yofunika. Zikomo potsatira, ndipo tikukhulupirira kuti izi zathandiza.
