Nā nīnau hoʻohālike e kūkākūkā ana i ke ʻano o nā Chromosomes i loko o ka Eukaryotic Nucleus
ʻO ke ʻano o ka chromosome kahi ʻano koʻikoʻi o ka biology cell, e hāʻawi ana i ka ʻike i ke ʻano o ka mālama ʻana, ka hoʻouna ʻana, a me ka hōʻike ʻana o ka ʻike genetic i loko o nā eukaryotes. Ma kēia ʻatikala, e wehewehe mākou i nā manaʻo kumu o ke ʻano o ka chromosome i loko o ka eukaryotic nucleus a hāʻawi i nā pilikia hoʻohālike a me nā hoʻonā e kōkua i kou ʻike.
Hoʻolauna i ke ʻano o nā Chromosome i loko o ka Eukaryotic Nucleus
ʻO nā chromosomes he mau ʻano koʻokoʻo i loaʻa i loko o ka nucleus o nā cell eukaryotic. Hana ʻia lākou me ka DNA a me nā protein i kapa ʻia ʻo histones. He kuleana koʻikoʻi kēia mau ʻano i ka hōʻoia ʻana ua kope pololei ʻia ka ʻike genetic a hoʻoilina ʻia i ka wā o ka mahele ʻana o ke kelepona. I loko o nā chromosomes, pelu a ʻōwili ka DNA a puni nā histones, e hana ana i nā ʻano i ʻike ʻia he mau nucleosomes. Hoʻopili hou aku kēia mau nucleosomes a pelu e hana i ka chromatin ʻoi aku ka paʻa, ʻoi aku hoʻi i ka wā o ka mahele ʻana o ke kelepona.
ʻAno kikoʻī o nā Chromosomes
1. DNA a me nā Nucleotides: Aia ka DNA i kahi kaulahao lōʻihi o nā nucleotides e hana ana i ke code genetic. Aia nā Nucleotides i ke kō deoxyribose, kahi hui phosphate, a me kekahi o nā kumu nitrogenous ʻehā: adenine (A), thymine (T), guanine (G), a me cytosine (C).
2. Nā Histones: Hana kēia mau protein ma ke ʻano he "coils" a puni ka DNA e wili ai. ʻElima ʻano histones e pili ana i ka hoʻokumu ʻana o ka nucleosome: H1, H2A, H2B, H3, a me H4.
3. Nucleosome: ʻO kēia ke ʻāpana kumu o ka hoʻonohonoho chromosome, i haku ʻia me kahi ʻāpana pōkole o ka DNA i kāʻei ʻia a puni kahi histone core.
4. Chromatin: Hoʻopili hou ʻia nā nucleosomes e hana hou ana e hana i kahi ʻano i ʻike ʻia ʻo chromatin. Hiki ke loaʻa ʻo Chromatin i ʻelua ʻano: heterochromatin (dense a inactive) a me euchromatin (loose a transcriptionally active).
5. Nā Chromatids kaikuahine: Ke hana ʻia ka hana hou ʻana o ka DNA, hana kēlā me kēia chromosome i ʻelua kope like i ʻike ʻia he mau chromatids kaikuahine, i hoʻopili ʻia ma ke kikowaena e kahi ʻano i kapa ʻia ʻo centromere.
Nā nīnau hoʻohālike a me nā kūkākūkā
Nīnau 1:
E wehewehe i nā ʻokoʻa nui ma waena o ka chromatin a me nā chromosomes.
Kūkākūkā:
ʻO Chromatin a me nā chromosomes ʻelua mau ʻano like ʻole o nā mea genetic i komo i ka hoʻoilina. ʻO Chromatin ke ʻano wehe a wehe ʻia o ka DNA i loaʻa i ka wā interphase o ke kaʻina hana cell, e ʻae ana i ke komo ʻana no ka transcription DNA a me ka replication. I ka hoʻohālikelike ʻana, ʻo nā chromosomes ke ʻano i hoʻopaʻa ʻia o ka chromatin i ʻike ʻia i ka wā mitosis a me meiosis; hoʻomaʻalahi kēia i ka hoʻolaha pololei ʻana o nā mea genetic i nā cell kaikamahine. ʻO ke kumu, aia ka ʻokoʻa nui i ke kekelē o ka condensation a me ka hana i ka wā o ke kaʻina hana cell.
Nīnau 2:
Pehea ka hopena o ke ʻano histone i ka hoʻopili ʻana o ka DNA i loko o ka nucleus o nā cell eukaryotic?
Kūkākūkā:
He kuleana koʻikoʻi ko nā Histones i ka hoʻopili ʻana a me ka hoʻonohonoho ʻana i ka DNA i loko o ka nucleus cell. Hoʻopiʻi maikaʻi ʻole ʻia ka DNA (ma muli o ka phosphate), ʻoiai he maikaʻi loa nā histones ma muli o ko lākou lysine a me ka arginine kiʻekiʻe. ʻAe kēia pilina i ka DNA e ʻōwili paʻa a puni ka histone core, e hana ana i ke ʻano nucleosome. Me ka ʻole o nā histones, e hakakā ka DNA lōʻihi a palupalu e noho i loko o nā cell, ʻaʻole hoʻi e hana pono. Hiki i nā Histones ke hana i nā hoʻololi kemika (e like me ka acetylation a me ka methylation), kahi e hoʻopilikia ai i ka hiki ke komo ʻana o ka DNA no ka transcription a me ka replication.
Nīnau 3:
He aha ke kuleana o ke centromere i ka mahele ʻana o ke kelepona a no ke aha he mea nui?
Kūkākūkā:
ʻO ke centromere kahi ʻāpana koʻikoʻi o ka chromosome e lawelawe ana ma ke ʻano he wahi hoʻopili no nā protein kikoʻī i kapa ʻia ʻo kinetochores i ka wā o ka mahele ʻana o ke kelepona. ʻO Kinetochores nā wahi hoʻopili no nā olonā microtubule nona ke kuleana no ka huki ʻana i nā chromatids kaikuahine i nā pou ʻē aʻe o ke kelepona mahele. ʻO ke kūlana pololei o ka centromere a me ka hoʻokumu ʻana o ke kinetochore kūpono he mea nui ia no ka hoʻolaha kūpono ʻana o nā chromosome a me ka pale ʻana i ka aneuploidy, kahi kūlana i loaʻa ai i nā cell kahi helu maʻamau ʻole o nā chromosome, hiki ke alakaʻi i nā maʻi genetic.
Nīnau 4:
No ke aha i manaʻo ʻia ai ʻo ka euchromatin he mea nui aʻe i ke kaʻina hana hoʻopaʻa leo ma mua o ka heterochromatin?
Kūkākūkā:
Ua manaʻo ʻia ʻo Euchromatin he mea nui i ka transcription no ka mea ʻoi aku ka palupalu o kona ʻano ma mua o ka heterochromatin, e ʻae ana i nā enzymes transcription e maʻalahi ke komo i ka DNA. ʻO ka hana nui o ka euchromatin ka hōʻike ʻana i nā genes e pono ai no ka hana cellular i kēlā me kēia lā. I ka hoʻohālikelike ʻana, loaʻa i ka heterochromatin nā genes i hana ʻole a ʻaʻole pono mau a noho paʻa mau e pale aku i ka transcription. ʻO ke kumu, ʻo ka euchromatin kahi ʻāpana genomic i ʻoi aku ka hana transcriptionally.
Nīnau 5:
Pehea e pili ai nā hoʻololi histone i ka hōʻike ʻana o ka gene? E hāʻawi i kahi laʻana o kekahi o kēia mau hoʻololi.
Kūkākūkā:
Hiki i nā hoʻololi ʻana o ka Histone ke hoʻopilikia i ka hōʻike ʻana o ka gene ma o ka hoʻololi ʻana i ke ʻano o ka chromatin a me ka hiki ke komo i ka gene i nā mīkini transcriptional. ʻO kekahi laʻana, ʻo ia ka histone acetylation, kahi i hoʻohui ʻia ai kahi hui acetyl i kahi koena lysine ma ka huelo histone. Hoʻemi kēia hoʻololi i ka hoʻouka maikaʻi o ka histone, hoʻonāwaliwali i ka pilina ma waena o nā histones a me ka DNA, a hopena i kahi ʻano chromatin hāmama. Hoʻonui kēia i ka hiki ke komo i ka DNA i nā mea transcription a me nā RNA polymerases, no laila e hoʻonui ana i ka hōʻike ʻana o ka gene.
Ka hopena
ʻO ka hoʻomaopopo ʻana i ke ʻano a me ka hana o nā chromosomes i loko o nā cell eukaryotic he mea nui ia no ka noiʻi holomua i ka biology molecular a me ka genetics. Ua hoʻolālā ʻia kēia pilikia kūkākūkā e hoʻonui i ka ʻike o nā haumāna a me nā mea noiʻi i ke ʻano o ka mālama ʻana a me ka hoʻonohonoho ʻana o nā meaola i ka ʻike genetic, a pehea e hiki ai i nā loli i kēia ʻano ke kōkua i nā hanana olaola like ʻole a me nā maʻi.
