USABO Questions and Verified Answers | Passed | A+

Eukaryote : An organism whose cells contain complex structures enclosed within membranes. The defining membrane bound structure thats sets them apart from prokaryotic cells is the nucleas or nuclear envelope within which the genetic material is carried. All species of large complex species are eukaryotes, including animals, plants and funghi. Euchromatin : This shows as pale areas in the nucleas under electro magnification. It is a less densly packed form of chromatin; 10% is even less condensed and in this form it can be actively transcribed to produce RNA. Heterochromatin : This shows as dark areas on the eukaryotic nucleas; it is densly packed chormatin (DNA and protein complex) which cannot be transcribed. Histones 2 : Special proteins around which DNA is wrapped. Lamins : Intermediate filament proteins which protect the structure of the nucleas, they polymerize to from a network of filaments that lie just within the nuclear membrane. The network of these filament proteins is called the nuclear lamina. Nuclear Lamina : The network of intermediate nuclear filament proteins (Lamins) which is located just below the nuclear membrane and is linked to the membrane and chromatin. Nuclear Pores : 9nm (approx) gaps in the nuclear envelope that allow the passage of RNA and ribosomes out of the nucleas and the entry of selected small proteins and small water soluble molecules. Prokarayotes : An organism of the kingdom of Monera, comprising the bacteria and cyanobacteria. Characterised by the abscence of a distinct, membrane bound nucleas or membrane bound organelles and by DNA that is not organised in to chromosomes. Also called moneran