ch.5 | the cell cycle Flashcards
from 5.1
what happens during the G1 stage of the cell cycle?
- cell increases numbers of organelles
- cell increases in size
from 5.1
during the _______ stage of the cell cycle, DNA replicates & genetic material is duplicated
S
from 5.1
during which stage does the cell prep for division?
G2 stage
from 5.1
during the ______ stage, cell division & cytokinesis occurs
M
from 5.1
why is apoptosis a necessary process?
it removes unwanted tissue & abnormal cells
cyclin is a(n) _____ signal that help control the timing of events in a cell’s life
internal
from 5.1
what is mitosis?
division of a cell’s nucleus & genetic material
from 5.1
what is the division of the cytoplasm called?
hint: this doesn’t occur in all cells
cytokinesis
from 5.1
cells contain _________ that initiate apoptosis. these are usually held in check by inhibitors but can be unleashed by internal or external signals.
enzymes
from 5.1
at the end of apoptosis, the cell’s piece are engulfed by __________
white blood cells
from 5.2
what are growth factors? where are their signals delivered?
external cell signals that tell the cell whether or not to divide; to the plasma membrae of target cells
from 5.2
proto-oncogenes & tumor suppressor genes control what?
a cell’s movement through the cell cycle
from 5.2
________________ encode proteins that then promote the cell cycle & prevent apoptosis
proto-oncogenes
from 5.2
tumor suppressor genes encode _________ that slow the cell cycle. what do they do to cells in the cell cycle?
proteins; inhibit cells from progressing through the cell cycle
from 5.2
mutations in either proto-oncogenes or tumor suppressor genes cause what?
the disruption of normal cell division & behavior
from 5.2
a population of divided altered cells is called a ________
tumor
from 5.2
what causes cells to stop at
a. checkpoint G1
b. checkpoint G2
c. checkpoint M
a. unfavorable conditions for cell division or DNA damage
b. unfinished DNA replication or DNA damage
c. chromosomes not loned up or not lined up correctly at metaphase plate
from 5.2
what is the difference between the function of oncogenes (mutated proto-oncogenes) and that of mutated tumor suppressor genes?
oncogenes encode proteins to over-promote the cell cycle & cause cells to abnormally divide; tumor suppressor genes inhibit the cell cycle, and their mutated forms express proteins that render checkpoints in the cell cycle useless
from 5.3
chromatin is a combination of
DNA & protein
from 5.2
what are histones
proteins that package DNA to fit into a small space in a cell
from 5.3
when a cell isn’t dividing, the chromatin _______ making the DNA available for ________
disperses/extends; gene expression
from 5.3
the cell condition in which 2 of each type of chromosome are present is called what?
diploid (2n)
from 5.3
what are haploids (1n)
cells w/ half the diploid number that containe only 1 of each type of chromosome
from 5.3
during mitosis, the chromosome number ___________
stays constant
