Ch. 12: Cell Cycle

mitosis

cell division to produce two identical cells

reproduction, growth and development, and tissue renewal

what’s mitosis essential for?

G1, S, G2

what are the 3 subphases in interphase?

true

the cell spends majority of its time being in interphase. true or false?

G1, 1st gap phase

during this phase, there is cellular growth, double organelle mass, double membrane mass, double cytoplasm

s, synthesis phase

during this phase, the nuclear DNA is replicated

G2, 2nd gap phase

during this phase, there is continued growth and preparation for cell division

prophase, prometaphase, metaphase, anaphase, telophase

what are the 5 subphases of mitosis?

chromosomes

a single piece of DNA; there are 46 of this in a human somatic cell

somatic cell

cells that are NOT gamete (sperm/egg)

chromatin

DNA + protein (histones, etc.) that can help organize DNA

long thin fibers

what is the organization of the DNA during interphase?

condensed supercoiled

what kind of organizing is the DNA during mitosis?

centromeres

location in which sister chromatids are held together

one

when the sister chromatids are held together at the centromeres during s phase, how many chromosome(s) is it?

each chromatid is a chromosome (2)

when sister chromatids are separated during mitosis into 2 chromatids, how many chromosome(s) is it?

MITOC

microtubule organizing center

mitotic spindle

consists of 2 centrosomes and microtubules

kinetochore

attach to the centromere of each chromosome forming what?

interphase

DNA duplicated but not condensed; intact nucleus

prophase

DNA begins to condense; mitotic spindle forms; nucleolus disappears

prometaphase

DNA fully condensed; nuclear envelope fragments; microtubules connects to kinetochore

metaphase

DNA lines up on metaphase plate

anaphase

sister chromatids separate

telophase

nuclear envelope reforms (2 nuclei); DNA decondenses

cytokinesis

division of plasma membrane; begins in late anaphase to early telophase; occurs via cleavage furrow (in animals); depends on microfilament

G1, G2, M

what are the 3 checkpoints to control a cell cycle?

G0

a cell that never divide enter a non-dividing phase called what?

muscles, neurons

examples of cells that are in G0 phase?

liver cells

examples of cells that can be “called back” to G1 phase

G1 check point

uses platelet derive growth factor; cells won’t divide if not given signal to divide

platelet derive growth factoor

signal molecules secreted from blood cells - received by fibroblast via receptor tyrosine kinase; allows fibroblast cells to pass G1 checkpoint

tyrosine kinase

what kind of receptor is used for platelet derived growth factor?

G2 checkpoint

MPF (M-phase promoting factor or maturation promoting factor) is needed to pass this checkpoint; made up of cyclin dependent kinase (CDK) and a cyclin

MPF

made up of a cyclin dependent kinase and a cyclin; used in G2 checkpoint for start of mitosis; phosphorylates other proteins for mitosis

cyclin dependent kinase

always present but inactive in absence of cyclin

cyclin

when present, it binds to CDKs to activate them

absence of growth signals, full contact with other cells, absence of surface to bind to

what are scenarios that normal cells stop dividing undre?

anchorage dependence

in the absence of a surface to bind to, cells stop dividing

density dependent inhibition

when cells are in full contact with other cells, they stop dividing

constitutively active

cancer cells have what pathway that - no longer need growth factor due to a mutation in the pathway