Nucleus Flashcards
Where do you see Barr bodies in samples?
small attachment to the nuclear envelope of epithelial cells or a drumstick appendage to PMN’s
What does the nucleolus do?
ribosomal RNA synthesis and ribosomal assembly
What are the 3 regions of the nucleolus and what do they do?
Fibrillar centers: loops of chromosomes contain DNA (look like holes)
Fibrillar material: genes being actively transcribed (dark areas)
Granular material: densely packed preribosomal particles (grainy)
What is the nuclear envelope?
2 membranes with a perinuclearcisternal space between them
What is the nuclear lamina?
network of protein filaments that serves as scaffolding/support
the nucleoplasm includes everything in the nucleus except what?
the chromatin and the nucleolus
What are the 2 checkpoints for G1?
Restriction point CP: mediated by retinoblastoma susceptibility protein
G1 DNA damage CP:mediated by tumor suppressing protein p53
What is the checkpoint for S phase?
S DNA damage CP
What are the checkpoints for G2?
G2 DNA damage CP
Unreplicated DNA damage CP
What are the checkpoints for M phase?
Spindle assembly checkpoint
chromosome segregation CP
What proteins power cells through the checkpoints?
Cyclin and clycin-dependent kinase
What are the sequential phases of Phophase I in Meiosis I?
Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis
What is the difference between necrosis and apoptosis?
Necrosis is pathological and apoptosis is physiolgical
