ʻAno RNA i nā ʻōnaehana genetic
ʻO ka waikawa Ribonucleic (RNA) kahi molekala koʻikoʻi i loko o ka ʻōnaehana genetic o nā mea ola āpau. ʻOiai ua kapa pinepine ʻia ʻo DNA ʻo ia ka "mālama" o ka ʻike genetic, hoʻokani ʻo RNA i kahi kuleana ikaika: kope ia, lawe, unuhi, a hoʻonohonoho pū i kēlā ʻike i hiki ke unuhi ʻia i nā hana olaola. ʻAʻole wale ka ʻokoʻa o RNA i kona kuleana akā i kona ʻano maʻalahi a ʻano like ʻole. ʻAe ke ʻano o RNA i kēia molekala e hana i nā hana he nui i ka manawa like, mai ka hoʻopili ʻana i ka hōʻike ʻana o ka gene a hiki i ka hoʻoulu ʻana i nā hopena biochemical. Kūkākūkā kēia ʻatikala i ke ʻano o RNA a me kona pilina me kāna hana i loko o ka ʻōnaehana genetic.
1. Ke hoʻomaopopo nei i ka RNA a me kāna mau ʻāpana
He polymer ka RNA i haku ʻia me nā ʻāpana hana hou i kapa ʻia ʻo nucleotides. ʻEkolu mau ʻāpana nui o kēlā me kēia RNA nucleotide: he kō ribose, he hui phosphate, a me kahi kumu nitrogenous. ʻO nā kumu nitrogenous i loko o ka RNA e komo pū me adenine (A), guanine (G), cytosine (C), a me uracil (U). ʻO nā ʻokoʻa koʻikoʻi mai ka DNA ʻo ia ka hoʻohana ʻana i ka uracil ma kahi o ka thymine a me ke ʻano o ke kō i hoʻohana ʻia (ribose i loko o ka RNA, deoxyribose i loko o ka DNA).
ʻO ke alo o kahi hui hydroxyl (-OH) ma ka ʻātoma kalapona 2' o ka ribose e hoʻolilo i ka RNA i mea pane hou a emi iki ka paʻa ma mua o ka DNA. Eia nō naʻe, he mea maikaʻi kēia "kūpaʻa ʻole" i nā pōʻaiapili olaola no ka mea ua hoʻolālā pinepine ʻia ka RNA ma ke ʻano he molekala manawa pōkole i hana koke ʻia a wāwahi koke ʻia e like me ka mea e pono ai e ke kelepona.
2. ʻAno mua: kaʻina nucleotide ma ke ʻano he code ʻike
ʻO ke ʻano mua o RNA e pili ana i ke kaʻina o nā nucleotides ma ke kaulahao RNA. Mālama kēia kaʻina i ka ʻike—ma ke ʻano he template no ka synthesis protein a ma ke ʻano he hōʻailona hoʻoponopono. I loko o ka messenger RNA (mRNA), ua hoʻonohonoho ʻia ke kaʻina nucleotide i nā codons ʻekolu-kumu i unuhi ʻia i loko o ke kaʻina amino acid o kahi protein. I nā ʻano RNA ʻē aʻe, e like me rRNA a i ʻole tRNA, hoʻoholo pū ke ʻano mua i ke kūlana o nā ʻāpana koʻikoʻi e hana ana i nā pelu hiʻona a me nā wahi hana.
ʻAʻole hana ka ʻōnaehana mua ma kahi kaʻawale. I loko o RNA, pili ka ʻike "coding" a me ka "structure": ʻaʻole wale ka moʻo kumu e hoʻoholo ai i ka leka genetic akā hoʻoholo pū kekahi i ka hiki o ka RNA ke hana i nā hui kumu kūloko e hana i nā ʻōnaehana pae kiʻekiʻe.
3. ʻAno lua: ka hoʻohui ʻana o ke kumu a me ka pelu ʻana maʻamau o ka RNA
ʻO ke ʻano lua o ka RNA ke ʻano o nā hui kumu intramolecular e hana ana i nā mea e like me nā helices, hairpins, loops, bulges, a me nā junctions. ʻO ke kumu nui o ka hui kumu ma RNA e hahai ana i ka lula hoʻopihapiha: nā hui A me U, a me nā hui G me C. Eia kekahi, hana pinepine ʻo RNA i nā hui kumu non-canonical e like me ka G-U wobble, he paʻa loa ia a he mea nui no ka hana o nā RNA he nui.
Hiki ke pelu lua no ka mea hiki i kahi kaula RNA hoʻokahi ke pelu hou a hana i nā pilina hydrogen ma waena o nā kumu hoʻohui ma nā wahi like ʻole. He mea nui kēia ʻano lua no ka mea:
1. Hoʻopaʻa i nā molekala RNA i loko o ke kaiapuni cellular ikaika.
2. Ke hoʻokumu nei i nā wahi ʻike no nā protein ʻē aʻe a i ʻole RNA.
3. Ke hoʻoponopono ʻana i nā kaʻina hana olaola, no ka laʻana ke hoʻoholo ʻana inā maʻalahi ka unuhi ʻana a i ʻole ke kāohi ʻia ʻana o kahi mRNA.
ʻO kahi laʻana maopopo ʻo ka tRNA, nona kahi ʻano lua e like me ka "cloverleaf." Aia kēia ʻano i kekahi mau lima, me kahi lima anticodon a me kahi lima mea hoʻokipa waikawa amino, nona kēlā me kēia hana kikoʻī.
4. ʻAno hana ʻekolu: ʻano ʻekolu-dimensional e hoʻoholo ai i ka hana
ʻO ke ʻano tertiary o ka RNA he ʻano ʻekolu-dimensional i loaʻa mai nā pilina hou aʻe ma waena o nā ʻāpana o ke ʻano lua. I kēia pae, hana ʻo RNA i kahi pelu paʻakikī ma o nā mana like ʻole, e like me nā pilina hydrogen hou, nā pilina hoʻopaʻa kumu, a me ke kōkua o nā ions (e.g., Mg²⁺) e hoʻopau i ka uku maikaʻi ʻole ma ke kuamoʻo phosphate.
He mea nui ke ʻano hana ʻekolu no ka mea, hilinaʻi ka nui o nā hana a RNA i kona ʻano ʻekolu-dimensional. Eia kekahi laʻana:
– ʻO ka hope loa, he ʻano L ko ka tRNA i loko o kahi ākea ʻekolu-dimensional. ʻAe kēia ʻano i ka hopena hoʻopaʻa waikawa amino e kau pololei ʻia e pili ana i ka anticodon e heluhelu ana i ka mRNA codon.
– ʻO rRNA ke kumu o ke kūkulu ʻana o ka ribosome, a ʻo kona pelu tertiary e hana i kahi "hale hana" unuhi pololei.
ʻO Ribozymes, ʻo ia hoʻi nā RNA catalytic, hilinaʻi nui lākou i nā ʻano tertiary e hana i nā wahi hana e like me nā enzymes protein.
No laila, ʻaʻole wale ka RNA he "ʻelele" maʻalahi. Hiki iā ia ke lilo i ʻano olaola paʻakikī a hana.
5. Nā ʻano o ka RNA a me nā pilina hana-ʻano
I loko o ka ʻōnaehana genetic, aia kekahi mau ʻano nui o ka RNA i ʻike nui ʻia:
a. mRNA (ʻelele RNA)
Lawe ka mRNA i ka ʻike genetic mai ka DNA i loko o ka nucleus (i loko o nā eukaryotes) i nā ribosomes i loko o ka cytoplasm no ka unuhi ʻana i loko o nā protein. ʻO ke ʻano o ka mRNA i loko o nā eukaryotes ma ke ʻano laulā e komo pū me kahi pāpale 5', kahi ʻāpana i unuhi ʻole ʻia (UTR), kahi papa heluhelu (ORF), a me kahi huelo poly-A ma ka hopena 3'. Hoʻopili kēia mau mea i ke kūpaʻa o ka mRNA, ka pono o ka unuhi ʻana, a me kahi o ka mRNA. i loko o ke kelepona.
b. tRNA (RNA hoʻoili)
Hana ʻo tRNA ma ke ʻano he mea hoʻololi e hoʻopili ana i nā codons mRNA me nā waikawa amino kūpono. ʻO ka lua o ka ʻōnaehana cloverleaf a me ʻO ke ʻano L-ʻano e hōʻoiaʻiʻo ana i ka hiki i ka tRNA ke: (1) ʻike ʻia e ka enzyme aminoacyl-tRNA synthetase, (2) komo i loko o ka ribosome, a (3) hoʻopili pololei i ka anticodon me ke codon.
c. rRNA (ribosomal RNA)
He ʻāpana koʻikoʻi ʻo rRNA o nā ribosomes a he kuleana koʻikoʻi kāna i ke kaʻina hana unuhi. ʻO ka mea hoihoi, he "ribozymes" nui nā ribosomes: ʻo ka ʻāpana catalytic o ka hoʻokumu ʻana i ka pilina peptide e hoʻokō nui ʻia e rRNA, ʻaʻole ka protein. ʻO ka hana holomua o nā ribosomes e hilinaʻi nui ʻia i ka ʻano paʻakikī o ka rRNA i pelu ʻia.
d. RNA hoʻoponopono
Ma waho aʻe o nā ʻano nui ʻekolu, hana nui nā RNA liʻiliʻi e hoʻoponopono i ke ka hōʻike ʻana o ka gene, no ka laʻana, miRNA (microRNA), siRNA (RNA liʻiliʻi e hoʻopilikia ana), a me lncRNA (RNA lōʻihi ʻaʻole coding). Loaʻa pinepine i nā ʻano RNA hoʻoponopono nā hairpins a i ʻole nā wahi hoʻohui kumu e ʻae iā lākou e nakinaki i nā mRNA i manaʻo ʻia a kāohi i ka unuhi a hoʻoulu paha i ka hoʻohaʻahaʻa mRNA.
6. RNA i ka hana hou ʻana, ka palapala ʻana, a me ka hana ʻana i nā ʻano hoʻoilina
Pili pololei ʻo RNA i nā pae like ʻole o ke kahe ʻana o ka ʻike genetic. I ka wā o ka transcription, hana ʻo RNA polymerase i ka RNA ma muli o kahi template DNA. I loko o nā eukaryotes, hana ʻia ka RNA hou (pre-mRNA) i ka hana ʻana: hoʻohui pāpale, splicing intron, a me ka polyadenylation. Hiki i ke ʻano RNA ke hoʻohuli i ka splicing, no ka mea, hiki i kekahi mau pelu ke hūnā a hoʻonui paha i nā wahi splicing.
Pili pū ka RNA i ka hana hou ʻana o kekahi mau virus. I loko o nā virus RNA , ʻo RNA ka mea genetic, no laila ua hoʻolālā pinepine ʻia ke ʻano RNA viral e lilo i mea kūpono loa: hiki iā ia ke hana ma ke ʻano he genome a me mRNA. Hoʻohana kekahi mau virus i nā ʻano RNA kikoʻī e pale aku i ka ʻōnaehana pale o ke kelepona a hoʻonui paha i ka pono o ka hana hou ʻana.
7. Kuanaʻike hoʻomohala: kuhiakau honua RNA
ʻO kekahi o nā manaʻo koʻikoʻi i ka biology evolutionary ʻo ia ka kuhiakau "RNA world". Hōʻike kēia kuhiakau i nā pae mua o ke ola, ua lawelawe paha ʻo RNA i kahi kuleana pālua ma ke ʻano he hale mālama ʻike genetic a he mea hoʻoulu no nā hopena, ma mua o ka māhele ʻana i loko o DNA (ʻoi aku ka paʻa no ka mālama ʻana) a me nā protein (ʻoi aku ka ʻokoʻa no ka catalysis). Kākoʻo ka maʻalahi o ke ʻano RNA i kēia manaʻo, ʻoiai hiki i ka RNA ke hoʻopili i ka ʻike i ka wā e pelu ana i loko o nā wahi hana catalytic.
Ka hopena
ʻO ke ʻano o ka RNA ke kikowaena o kāna kuleana i ka genetics. Mai kona ʻano mua, kahi e mālama ai i nā moʻo nucleotide, a i kona ʻano lua, kahi e hana ai i nā pelu e like me ka hairpin, a i kona ʻano tertiary, kahi e hana ai i nā hana ʻekolu-dimensional paʻakikī, hōʻike ʻo RNA i nā hiki kū hoʻokahi ma ke ʻano he mole multifunctional. ʻO nā ʻano like ʻole o RNA e ʻae iā ia e hana ma ke ʻano he mea lawe ʻike, mea hoʻololi unuhi, mea kūkulu ribosome, mea hoʻoponopono hōʻike gene, a me kahi mea hoʻoulu olaola. ʻO ka hoʻomaopopo ʻana i ke ʻano o ka RNA ʻo ia hoʻi ka hoʻomaopopo ʻana i kekahi o nā kumu kumu o ke ola, e hoʻomākaukau ana i ke ala no nā noi biotechnological a me nā noi lapaʻau e like me nā lāʻau lapaʻau RNA, nā lāʻau lapaʻau mRNA, a me ka kaohi pololei o ka hōʻike ʻana o ka gene.
