Organela · dvostruka membrana

Jedro

Kontrolni centar

U kadru

Svaka boja označava jedan par hromozoma, a svaka kopija zauzima sopstvenu teritoriju, kao na snimcima bojenja hromozoma. Tamnije, deblje deonice su heterohromatin, koji oblaže omotač i jedarce. Ova ćelija je ženska (XX): jedan X je isključen i spakovan u gusto Barovo telo uz omotač. Kroz pore izlaze RNK i delovi ribozoma, a ulaze proteini.

Jedro čuva genom: oko 6,3 milijarde slova DNK koja bi se, razvučena, protegla 2 metra, a spakovana su u loptu prečnika 5–10 µm. Više od trećine genoma nalazi se u utišanim, gusto zbijenim deonicama (heterohromatinu) priljubljenim uz jedrovu laminu, tanku mrežu filamenata lamina koja oblaže unutrašnjost jedra.

Obavijaju ga dve membrane probušene hiljadama pora. Svaka pora je prsten koji spaja dve membrane, sastavljen od oko 30 vrsta proteina, a s unutrašnje strane ima korpu. Unutra ćelija odlučuje koji će se geni prepisati u RNK, a time i šta će postati i šta će raditi.

Prečnik

5–10 µm

DNK

≈ 2 m · 6,3 milijarde pb

Hromozomi

46

Jedrove pore (HeLa)

≈ 2.800

Da li ste znali?

DNK je oko 270.000 puta duža od širine jedra. To je kao da u tenisku lopticu ugurate 18 km strune za pecanje.

Izvori

1. Chromosome territories · Cremer & Cremer 2010 · Cold Spring Harb Perspect Biol
2. Kinetic analysis of translocation through nuclear pore complexes · Ribbeck & Görlich 2001 · EMBO J
3. Lamina-associated domains: links with chromosome architecture, heterochromatin, and gene repression · van Steensel & Belmont 2017 · Cell
4. Nucleolar organizer regions: genomic 'dark matter' requiring illumination · McStay 2016 · Genes Dev
5. A morphological distinction between neurones of the male and female, and the behaviour of the nucleolar satellite during accelerated nucleoprotein synthesis · Barr & Bertram 1949 · Nature
6. Structural aspects of the inactive X chromosome · Bonora & Disteche 2017 · Phil Trans R Soc B
7. On the length, weight and GC content of the human genome · Piovesan et al. 2019 · BMC Res Notes
8. Nuclear diameter · BioNumbers · BNID 100440
9. The molecular architecture of lamins in somatic cells · Turgay et al. 2017 · Nature
10. How big is the endoplasmic reticulum of cells? · Milo & Phillips · Cell Biology by the Numbers
11. The cellular environment shapes the nuclear pore complex architecture · Schuller et al. 2021 · Nature
12. The nuclear pore complex: understanding its function through structural insight · Beck & Hurt 2017 · Nat Rev Mol Cell Biol
13. Nucleoporins as components of the nuclear pore complex core structure and Tpr as the architectural element of the nuclear basket · Krull et al. 2004 · Mol Biol Cell
14. 4.3 Eukaryotic Cells · OpenStax · Biology 2e
15. How many chromosomes do people have? · MedlinePlus Genetics (NIH)