Cell 7 Flashcards
Where is nuclear lamina located?
just deep to the inner nuclear membrane
What makes up the nuclear lamina?
3 different types of intermediate filaments referred to as lamins
What’s the function of lamins?
they are involved with disassembly and re-assembly of nuclear envelope during mitosis
What causes Progeria?
defect in nuclear lamins
What is the role of lamins in prophase of mitosis?
disassembly of nuclear enevelope, mediated by phosphorylation of the lamins making up the nuclear lamina
What is the role of lamins in telophase of mitosis?
reassembly of nuclear envelope, dephosphorylation of lamins
What is heterochromatin?
tightly coiled chromatin
What is euchromatin?
loosely coiled chromatin
Which will stain more densely, heterochromatin or euchromatin?
heterochromatin will stain more densely in a basic dye
What is the distinctive feature in a stain for papillary thyroid cancer?
Orphan Annie eye nuclei “clear eye”
What is nucleostemin?
p53 binding protein found in undifferentiated cells.
As cells become more differentiated, what happens to the level of nucleostemin?
decreases thus p53 is active and functional, and can control the cell cycle
The presence of nucleostemin in cancer cells is indicative of what?
unchecked proliferation due to the inactivation of p53
What is in pars fibrosa within the nucleolus?
heavy ribosomal RNA, proteins coming in from the cytoplasm also go here
What is in pars granulosa within the nucleolus?
maturation of ribosomal subunits and appear more granulated
What are the phases of interphase?
G1, S, G2
What occurs in G1?
restriction checkpoint before proceeding to S phase, most variable stage in terms of length
What occurs in S phase?
duplication of DNA, contains S DNA-damage checkpoint
What occurs in G2?
prepares cell for mitosis and also contains G2 DNA-damage checkpoint