72 terms

ch 9 cell cycle

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somatic cells
non reproductive
2 sets of chr
diploid
diploid
2n
gametes
haploid reproductive cells (sperm & egg), unite during reproduction to produce diploid zygote
haploid
n
binary fussion
cell splits into 2 cells
septation
new cm and cw forms between cells
protein control
FtsZ facilitates septation
DNA
40% of chr
neg charged
protein
60% of chr
histone protein pos charged
nucleotides
PO4, ribose, nitrogenous base, 300 million
histone proteins
every 200 million
DNA is coiled around these
nucleosome
DNA and 8 proteins
chromatin
complex of uncondensed DNA and proteins
heterochromatin
permanently condensed DNA
genes on are NOT used
centromere is region of
euchromatin
does uncoil
genes on ARE used
gene
region of DNA on chr
locus
location of gene
sister chromatid
copy of chr
centromere
holds sister chromatids together
repetitive DNA sequences
position varies for diff chr
homolog
one of a pair of chr
genome
genetic material of organism or virus, can consist of single DNA molecule (prokaryotic) or # of DNA molecules ( eukaryotes)
walther flemming
1882 developed dyes to observe chr during mitosis and cytokinesis
phases of cell cycle
mitotic (M) phase and interphase
mitotic (M) phase
including mitosis and cytokinesis
interphase
including cell growth and coping of chr in preparation for cell division
eukaryotic cell cycle
duration depends on cell type and species
majority of cells time is spent in interphase
mitosis phases
prophase
prometaphase
metaphase
anaphase
telophase
interphase prep for mitosis
NE visible
nucleolus visible
chr NOT visible using light microscope
G1
cell grows, before DNA synthesis
S phase
DNA and proteins are synthesized and chr are replicated
one unreplicated chr > one replicated chr
centrosomes
contain centrioles
orient mitosis events
initiate microtubule formation
centrioles
replicate so each new cell will have 1 pair
site of microtubule synthesis
kinetochore
disk shaped region that allows microtubule attatchment
microtubules
move chr
condensation
coiling of chromatin
G2
mitochondria replicate
chromosomes condense
microtubules are sysnthesized
phrophase
spindle assemblies centrioles move to opposite ends
microtubule assemblies form
cytoskeleton breaks down
asters: around centrols
spindles: to chr
NE disappears
condensation of chr cont
metaphase
spindle is complete at chr, attached to microtubules at their kinetochores, all aligned at metaphase plate
anaphase
sister chromatids pull apart move toward opposit ends
removal of cohesin proteins causes centromeres to separate
microtubules pull sister chromatids toward poles
animal cells elongate
anaphase A
kinetochores pulled apart
anaphase B
poles move apart
telophase
chromatids at opposite ends
spindle assemblies break apart into recyclable tubulin subunits
NE reforms around each set of chr
cytokinesis in animal cells
contracting band of pilaments pinches cell in 2, cleavage
cytokinesis in plant cells
cell plate forms in middle of cell
cytokinesis in fungi and some protists
mitosis occurs within nucleus
division of nucleus occurs with cytokinesis
checkpoints G1/S
cell decides to divide
G1 cyclins accumulate and bind with Cdk2 to create G1/S Cdk
G1/S Cdk phosphorylate # of molecues that increase enzymes required for DNA replication
MOST IMPORTANT checkpoint
if receive go ahead signal cell with complete the S, G2, and M phases and divide
G 0 phase
if cell does NOT recieve go ahead signal will exit cycle switching into non dividing state
G 2/M checkpoint
cell makes commitment to mitosis
if DNA damaged mitosis should not progress
control of cell cycle
MPF
maturation promoting factor (MPF)
positive regulator of cell cycle
activates via phosphorylation
cyclin and kinase
cyclins
proteins produced with cell cycle
regulate cell through checkpoints
cyclin-dependent kinase (Cdk)
enzymes that drive cell cycle
activated only when bound by cyclin
bind with cyclin triggering S phase
introduce cell division
cyclin D-Cdk 4
acts of restriction point
rest of cycle will occur
cyclin E-Cdk 2
initiates DNA replication
controls duplication of chr
cyclin A-Cdk 2
initiates DNA replication
cyclin B-Cdk 1
starts chromosomes coiling, mitosis
growth factors
protein needed for growth and development in cells
circulate in body
type of external factor
can bind only to certain target cells via unique receptor proteins
once bound the receptor catalyzes cell division rxns
platelet derived growth factor
released by platelets if wound occurs
diffuses to cell
stimulates diffusion
interleukins
made by WBCs
promote division in immune cells
erythropoletin
made in kidney
stimulates RBC and marrow production
density-dependent inhibition
causes cells to stop dividing when come in contact with another external signals
crowded cells
anchorage dependence
must be attached to substratum in order to divide
cancer cells
do not respond to signals that normally regulate the cell cycle
dont need gf to grow and divide
make own gf
convey gf signal without presence of gf
have abnormal cell cycle control system
p53 is absent or damaged
genes that can disturb cell cycle when mutated
tumor-suppressor genes (TSGs)
proto-oncogenes
proto-oncogenes
encode receptors for gf
encode signal transduction proteins
become oncogenes when mutated
oncogenes can cause cancer when introduced into cell
tumor-suppressor genes (TSGs)
prevent development of many cells containing mutations
transformation
normal cell converted to cancerous cell
cancer cells that are not eliminated by immune system form tumors
tumors
masses of abnormal cells within otherwise normal tissue
benign tumor
abnormal cells remain only at original site
malignant tumor
invade surrounding tissues
can metasize
metastasis
spread of cancer cells to locations distant from original site
chromosomes
cellular structure consisting of one DNA molecule and associated protein molecules