Flashcards in Cell biology VII Deck (33):
Is the nucleolus membrane-bound?
Now many nucleoli are present in a typical cell?
What are the three components of the nucleolus?
1) Nucleolar-organizer DNA2) Pars fibrosa3) Pars granulosa
What is the function of nucleolar-organizer DNA?
Contains base sequence that codes for transcription of rRNA
What is the function of the pars fibrosa?
Newly transcribed rRNA just beginning to become complexed with proteins
What is the function of the pars granulosa?
Maturing subunits of ribosomes
What is nucleostemin?
p53 binding protein found in undifferentiated cells
What happens to the levels of nucleostemin as the cell becomes more differentiated?
During what phase of the cell cycle does replication of centrioles begin?
During what phase of the cell cycle is centriole replication complete?
What events take place during prophase?
1) Chromatids are condensed2) Tetrads form3) Centromere forms4) Kinteochore forms5) Cytoplasmic microtubules are disassembled and reorganized into mitotic spindle6) Centriolar pairs migrate to opposite ends
During what phase of the cell cycle are chromatids condensed?
During what phase of the cell cycle do tetrads form?
During what phase of the cell cycle does the centromere form?
During what phase of the cell cycle does the kinetochore form?
During what phase of the cell cycle do microtubules disassemble and reorganize into mitotic spindle?
During what phase of the cell cycle do centriolar pairs migrate to opposite ends of the cell?
What is the starting point for prometaphase?
Disappearance of nuclear envelope
What events take place during prometaphase?
1) Nuclear envelope dissolves2) Attachment of microtubules to kinetochores3) Chromatids organize at equator of cell4) Nucleoli disappear
During what phase of the cell cycle are microtubules attaching to the kinetochore?
During what phase of the cell cycle are chromatids organizing at the equator of the cell?
During what phase of the cell cycle does the nucleolus disappear?
What drug will arrest development at metaphase?
At what phase of the cell cycle does colchicine cause arrested development?
What events take place during anaphase?
Chromatids separate and are referred to as chromosomes
Telomerase is found in what cell types?
Germinal cells and stem cells
What happens when phosphatidylserine is translocated to the extracellular lipid monolayer?
Cell is marked for death
What are the characteristics of extrinsic pathway for caspase activation?
1) Fas ligand and Fas receptor (death receptor)2) Adaptor protein3) Inactive caspase 8 ----> active caspase 8
What are the characteristics of intrinsic pathway for caspase activation?
1) Cell injury causes release of cytochrome c2) Cytochrome c adaptor protein (Apaf-1) complex forms3) Inactive caspase 9 ----> activated caspase 9
What effect does estrogen have on osteoblasts?
What is the normal role of Bad?
When phosphorylated, is Bad active or inactive?