Question: Cell Cycle Defined

Answer: refers to the series of coordinated events in which the cell duplicates its contents and divides in two.

For a cell to remain in equilibrium, it must double its mass each division cycle, including its organelles, proteins, and other biomolecules.

Question: Cell Cycle Phases

Answer: -M Phase-nucleus and cell division; mitosis and cytokinesis

-Interphase-G1, G0, S, and G2 phase

Question: Cleavage divisions

Answer: the first cell divisions in animal embryos after fertilization in which the giant cell subdivides into smaller cells with little to no growth in the short G1 and G2 phases.

Question: Checkpoints

Answer:

Question: G1 Checkpoint

Answer: aka “Start”. Cell confirms that nutrients and specific signal molecules in the extracellular environment are present to determine if conditions are favorable to commit to S phase. If not, may enter G0 phase.

Question: G2 Checkpoint

Answer: Cell cycle control system ensures that all damaged DNA is repaired and all DNA is replicated before entering to the M phase of the cell cycle.

Question: Mitosis Checkpoint

Answer: All replicated chromosomes must be properly attached to the mitotic spindle, before the spindle pulls the chromosomes apart into two daughter cells.

Question: Major Cell Cycle Regulators

Answer: Cyclins and Cyclin-dependent protein kinases are the major regulators of cell cycle progressions.

Question: Cyclins

Answer: cell-cycle regulatory proteins whose concentration gradually rises and falls at specific times in the cell cycle.

It binds to and activates specific cyclin-dependent protein kinases (Cdks).

Question: Cyclin-dependent protein kinases (Cdks)

Answer: master regulators of the cell cycle that phosphorylate and regulate other proteins that act in the cell cycle. .