cell cycle, mitosis, and meiosis Flashcards
what are some of the reasons why cell division occurs in multicellular organisms?
growth, replace dead/injured cells, development (changing form), reproduction, and different tissues may need more cells depending on function and enviornment
what is interphase?
period between divisions in the cell cycle
what happens during G0 phase?
nondividing state; where cells that do not pass the G1 checkpoint go
what happens during G1 phase?
RNA and protein synthesis occurs (no DNA synthesis yet)
what happens during S phase?
DNA synthesis/replication occurs
what happens during G2 phase?
RNA and protein synthesis occur and cell size increases (in preparation for mitosis or meiosis)
what happens during the M phase?
- mitosis - division of nucleus
- cytokinesis - division of cytoplasm
two daughter cells are produced
what are somatic cells?
cell that forms the body of multicellular organisms
what are gametes?
cells involved in reproduction; sex cells
what is mitosis?
part of M phase and is the process involving the division of the nucleus in which chromosome #/cell stays the same
what is cytokinesis?
division of the cytoplasm; final step of cell cycle
what happens at the G1 checkpoint?
checking for the right time, right place, and right number, as well as if the DNA was made correctly; cells that do not pass this checkpoint go into the G0 phase
what happens at the G2 checkpoint?
checking to make sure the DNA looks okay and that the chromosomes are replicated
what happens at the M checkpoint?
checking to make sure sister chromatids are correctly attached to the spindles that seperate them
what are cyclins?
proteins required to activate kinase subunits of CDKs; increase/decrease in and out of sync with cell cycle
what are cyclin dependant kinases?
aka CDKs, catalyze addition of phosphate groups from ATP to target proteins involved in cell cycle (phosporylation activates/deavtivates target proteins; enzyme that adds phosphate
how do cyclins and CDKs regulate cell cycle?
cyclin activates protein kinase forming a cyclin-cdk complex, this complex then acts as a signal to the cell to pass to the next phase of the cell cycle; proteolysis deactivate protein kinase
what happens when cell cycle control is lost?
cancer happens when control to cell cycle is lost and there is no regulation; cancer cells have abnormal characteristics, including immortality, no density-dependant inhibiton, and no anchorage dependance.
chromatid
one chromatin supramolecule (DNA and protein molecule); half of a duplicated chromosome
what is prophase?
first phase of mitosis where chromatin condenses, centrosomes move to opposite poles and microtubles/asters begin to form; nuclear envelope is still visible
what is metaphase?
second phase of mitosis where the chromosomes line up on the metaphase plate; mitotic spindle
what is anaphase?
third phase of mitosis where sister chromatids separate to daughter chromosomes. daughter chromosomes move toward poles and centrosomes pushed apart by non-kinetochore microtubules
what is telophase?
fourth phase of mitosis where microtubules elongate cell and daughter chromosomes move to poles, nuclear envelope reforms, chromatin relaxes and cytokinesis begins