Module 3: Lesson 8 Flashcards
(19 cards)
What are the two regulation points in mitosis?
M-Cdk drives the cell into mitosis, and APC transitions to anaphase.
What does M-Cdk do in M phase?
Trigger chromosome condensation (prophase), induces the assembly of the mitotic spindle (prophase), promotes the breakdown of the nuclear envelope (prometaphase), and activates APC complex required for degradation of cohesins (anaphase).
What is prophase?
Two DNA molecules are gradually disentangled and condensed into pairs of rigid and compact rods called sister chromatids, which remain together by sister chromatid cohesion. Outside the nucleus, the mitotic spindle assembles between two centrosomes.
What is prometaphase?
The nuclear envelope disassembles. The sister chromatid pairs can now attach to spindle microtubules.
What is metaphase?
All sister chromatids align at the spindle equator.
What is anaphase?
The sister chromatids synchronously separate and are pulled slowly toward opposite poles of the spindle.
What is telophase?
The spindle is disassembled, and the segregated chromosomes are packaged into separate nuclei.
What is a centrosome?
A microtubule organizing center that sits near the nucleus in an animal cell.
What are condensins activated by?
M-Cdk phosphorylation.
What is an aster?
A radial array of microtubules nucleated by the centrosome during mitosis.
What are interpolar microtubules?
Interacting microtubules from different centrosomes.
How is the nuclear envelope broken down in prometaphase?
The phosphorylation of lamins and nuclear pore complex (NPC) proteins by M-Cdk triggers disassembly and dispersal of nuclear envelope into small vesicles which are reused in daughter cells.
What are kinetochores?
Giant protein complexes that assemble on the centromere of each condensed chromosome. Tension signals correct attachment of chromosomes.
What is anaphase A?
The initial poleward movement of the chromosomes through a shortening of kinetochore microtubules. Microtubule depolymerization at both ends.
What is anaphase B?
The separation of the spindle poles themselves (poles move apart by action of motors on the interpolar and astral microtubules).
What occurs in nuclear resolution at the end of telophase?
Kinetochore microtubules depolymerize, interpolar microtubules elongate further and continue to push spindle poles apart, nuclear envelope reforms, condensed chromatin decondenses and expands, nucleolus reforms, contractile ring forms, and cytoplasm division begins.
What are the traits of cancer?
Sustaining proliferative signaling, evading growth suppressors, avoiding immune destruction, enabling replicative immortality, tumor-promoting inflammation, activating invasion and metastasis, inducing angiogenesis, genome instability and mutation, resisting cell death, and deregulating cellular energetics.
What types of extracellular signals are there?
Endocrine, paracrine, autocrine, juxtacrine, synaptic, and mechanical forces.
What are the common strategies for achieving self-sufficiency?
Produce mitogen and respond to it, creating a positive feedback loop. Over-express receptor, creating hyper-responsive reaction to normal levels of mitogen. Alter downstream cytoplasm circuitry to enable ongoing stimulation.
