13 - Cell cycle and mitosis Flashcards
Somatic cells
all body cells except the reproductive cells
cell cycle
the life of a cell from the time it is first formed during division of a parent cell until its own division into two daughter cells
Mitotic phase (M)
includes both mitosis and cytokinesis, shortest part of the cell cycle
Interphase
Much longer stage, accounts for 90% of the cycle. Interphase can be divided into three phases
G1 phase
“first gap”
S phase
“synthesis”
G2 phase
“second gap”
Mitosis
the division of the genetic material in the nucleus
Prophase
is the first stage of mitosis, cells chromosomes have become visible as they condense and thicken
Prometaphase
the stage of mitosis that follows prophase. The nuclear membrane completely breaks down, allowing chromosomes to spread out within the cell
Metaphase
Stage of mitosis where the chromosomes line up in the middle of cell
Anaphase
the stage of mitosis where the chromosomes are pulled apart
Telophase
the stage of mitosis where the cell starts to finish dividing
Cytokinesis
the division of the cytoplasm
Centromeres
a region made up of repetitive sequences in the chromosomal DNA where the chromatid is attached most closely to its sister chromatid
Centrioles
small cylindrical structures that help organize the movement of chromosomes during mitosis.
Mitotic spindle
begins to form in the cytoplasm during prophase. yellow string things
Aster
a star-shaped structure that forms around each centrosome during mitosis
Kinetochore
A structure made up of proteins that have assembled on specific sections of DNA at each centromere
Kinetochore microtubules
special fibers that attach to a specific part of the chromosome called the kinetochore
Non-kinetochore microtubules
fibers that do not attach to the chromosomes during mitosis. Instead, they overlap with the MTs from opposite side of cell
Metaphase plate
is an imaginary plate rather than an actual cellular structure
Cleavage furrow
a shadow groove in the cell surface near the old metaphase plate
Cleavage
the process where a single cell divides into two daughter cells
Cell cycle control system
A cyclically operating set of molecules in the cell that both triggers and coordinates key events in the cell cycle
Checkpoints
a control point where stop and go-ahead signals can regulate the cell. Three important ones are found in G1, G2, and M phases.
