cell cycle Flashcards
What are the two major phases of the cell cycle?
Interphase and Mitotic phase (M phase).
During which phase does the cell spend most of its life?
Interphase.
What happens during interphase?
The cell performs normal functions and prepares for division.
What are the three sub-phases of interphase?
G1, S, and G2 phases.
What occurs in the G1 phase?
Cell growth, energy accumulation, and protein synthesis.
What key event happens during the S phase?
DNA replication and formation of chromosomes.
What occurs during the G2 phase?
Energy replenishment, further protein synthesis, and cytoskeleton disassembly.
What are the four stages of mitosis?
Prophase, Metaphase, Anaphase, Telophase.
What has already occurred before a cell enters prophase?
DNA replication.
What are key events in prophase?
Chromosomes condense, nucleolus breaks down, spindle formation begins.
What happens to the nuclear envelope during metaphase?
It breaks down.
What is the key event of metaphase?
Chromosomes align at the spindle equator and attach to spindle fibers.
What happens to sister chromatids during anaphase?
They separate at the centromeres and move to opposite poles.
What assembles during anaphase besides chromatid movement?
The central spindle and the cleavage furrow.
What occurs during telophase?
Nuclear envelope reassembles and the cleavage furrow constricts.
What is cytokinesis?
Final separation of the two daughter cells.
What enzymes regulate progression through the cell cycle?
Cyclin-dependent kinases (Cdks).
How are Cdks activated?
By binding to specific cyclin proteins.
What is the function of Cdks?
They phosphorylate target proteins to drive cell cycle events.
What are the three major cell cycle checkpoints?
G1/S (Start), G2/M, and metaphase-anaphase transition.
What is checked at the G1/S checkpoint?
Cell size, nutrients, DNA integrity, and growth signals.
What is monitored at the G2/M checkpoint?
DNA replication completeness and damage repair.
What is verified at the metaphase-anaphase transition?
Proper chromosome alignment and attachment to spindle fibers.
What phase immediately follows telophase?
Cytokinesis.
