20 terms

Chapter 12: The Cell Cycle

Cell Cycle
The life of a cell from the time it is first formed from a dividing parent cell until its own division into two cells
somatic cell
All body cells except the reproductive cells
Reproductive cells (sperm and egg cells)
sister chromatid
Two chromatids each containing an identical DNA molecule
The region where two chromatids are attached
The division of the cell's nucleus
The division of the cytoplasm right after mitosis
90% of the cell cycle where cells grow and copy chromosomes in preparation for cell division
G1 phase
The phase of the cell cycle where the cell grows
S Phase
The phase of the cell cycle that copies chromosomes
G2 phase
The phase of the cell cycle where the cell grows more as it completes preparations for cell division
The phase of mitosis where the chromatin becomes more tightly coiled into discrete chromosomes, the nucleoli disappears, and the mitotic spindle begins to form in the cytoplasm
The phase of mitosis where the nuclear envelope begins to fragment, the two chromatids of each chromosome are held together by a kinetochore at the centromere, and the microtubules attach to the kinetochores
The phase of mitosis where the microtubules move the chromosomes to the metaphase plate and the centrioles have moved to opposite poles in the cell
The phase of mitosis where sister chromatids begin to separate and the cell elongates with the help of motor molecules; by the end of this phase the opposite ends of the cell both contain complete and equal sets of chromosomes
The phase of mitosis where the nuclear envelopes re-form around the sets of chromosomes, the chromatin fiber of the chromosomes becomes less condensed, and then cytokinesis begins
Cell cycle control system
A system of checkpoints during the cell cycle that includes the G1 phase checkpoint, G2 phase checkpoint, and M (mitotic) phase checkpoint
The protein enzyme that controls the cell cycle; they exist in the cells at all times but are active only when they are connected to cyclin proteins
Density-dependent inhibition
The process in which crowded cells stop dividing
Anchorage dependency
A type of dependency in which normal cells must be attached to a substratum to divide