Alberts, Ch 17 - Cell Cycle Flashcards
Anaphase A
Stage of mitosis, initial poleward movement of the chromosomes during which kinetocore microtubules shorten
Anaphase B
Stage of mitosis when spindle poles separate and daughter chromosomes move toward opposite poles
Anaphase-promoting complex (APC/C)
Ubiquitin ligase that catalyzes ubiquitylation and destruction of securin and M- and S-cyclins initiating separation of sister chromatids in metaphase-to-anaphase transition during mitosis, also known as cyclosome
Astral microtubule
In the mitotic spindle any of the microtubules radiating from the aster which are not attached to kinetochore of a chromosome
ATM
Ataxia telangiectasia mutated protein, protein kinase activated by double-strand DNA breaks, if breaks not repaired ATM initiates signal cascade that culminates in cell cycle arrest
ATR
Ataxia telangiectasia and Rad3 related protein, protein kinase activated by DNA damage, if damage remains unrepaired helps initiate signal cascade that culminates in cell cycle arrest
Bi-orientation
Attachment of sister chromatids to opposite poles of mitotic spindle so that they move to opposite ends of the cell when they separate in anaphase
Bivalent
Four-chromatin structure formed during meiosis consisting of a duplicated chromosome tightly paired with its homologous duplicated chromosome
Cdc20
Activating subunit of anaphase-promoting complex
Cdc25
Protein phosphatase that dephosphorylates Cdks and increases their activity
Cdc6
Protein essential in preparation of DNA for replication, with Cdt1 binds to origin recognition complex on chromosomal DNA and helps load the Mcm proteins onto the complex to form prereplicative complex
Cdh1
Activating subunit of anaphase-promoting complex
Cdk inhibitor protein (CKI)
Protein that binds to and inhibits cyclin-Cdk complexes, involved in control of G1 and S phases
Cdk-activating kinase (CAK)
Protein kinase that phosphorylates Cdks in cyclin-Cdk complexes activating Cdk
Cdt1
Protein essential in preparation of DNA for replication, with Cdc6 binds to origin recognition complexes on chromosomes and helps load the Mcm proteins on to the complex forming prereplicative complex
Cell cycle
Reproductive cycle of a cell, orderly sequence of events by which cell duplicates its chromosomes and other cell contents and divides into two
Cell-cycle control system
Network of regulatory proteins that governs progression of eukaryotic cell through cell cycle
Centrosome
Centrally located organelle of animal cells that is primary microtubule-organizing center (MTOC) and acts as the spindle pole during mitosis, contains a pair of centrioles
Chiasma (plu. Chiasmata)
X-shaped connection visible between paired homologous chromosomes during meiosis, represents a site of chromosomal crossing-over, form of genetic recombination
Condensin
Complex of proteins involved in chromosome condensation prior to mitosis, target for M-Cdk
Contractile ring
Ring containing actin and myosin that forms under the surface of animal cells undergoing cell division, contracts to pinch the two daughter cells apart
Cyclin
Protein that periodically rises and falls in concentration in step with eukarotic cell cycle, activates protein kinases (Cdks) and helps control progression from one stage of cell cycle to the next
Cyclin-dependent kinase (Cdk)
Protein kinase that has to be complexed with cyclin protein in order to act, different cyclin-Cdk complexes trigger different steps in cell-division cycle by phosphorylating specific target proteins
Cyclin-Cdk complex
Protein complex formed periodically during eukaryotic cell cycle as level of particular cyclin increases, Cdk then becomes partially activated
Cytokinesis
Division of cytoplasm of cell into two, distinct from associated division of its nucleus, part of M phase
E2F protein
Transcription regulatory protein that switches on many genes that encode proteins required for entry into S phase
G0
State of withdrawal from eukaryotic cell-division cycle by entry into quiescent digression from G1 phase, common, sometimes permanent state for differentiated cells
G1 phase
Gap 1 phase of eukaryotic cell cycle, between end of mitosis and start of DNA synthesis
G1-Cdk
Cyclin-Cdk complex formed in vertebrate cell by G1-cyclin and corresponding Cdk