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2025iUpdate|New!!
Lessoni1:iFoundationsitoiSetitheiStage:
FocusingioniCellulariStructureiandiFunction:
1. TheiNormaliCelliCycle:i-
TheicellicycleirefersitoitheiorderediseresiofiprocessesofiDNAireplicatio
niandimitosis,ioricellidivision
-
Cellinucleusiregulatesitheseiprocessesibyigatheringiandiprocessin
gicomplexesimoleculariinformation
2. InterphaseiandiMitoticiPhase:iCellidivisioniproducesitwoiiden
ticalicellsthroughitheseitwoimajoriphases
3. Duringiinterphase::iCelligrowsiandiDNAiisireplicatedithroughit
heifollowingthreeisteps:
1:iFirstigrowthiphasei(G1iorifirstigap)2:
Synthesisiphasei(Siphas
e)i3:MitoticiPhsei(Mipha
se)
4. FirstiGrowthiPhasei(G1iorifirstigap):i-cellsiincreaseiinisize
-reproduceiRNA
-"qualityiassurance"itestithatitheicelliwillibeireadyitoisynthesisiDNA
-Lengthiofitimeiisivariable,icanibeifromihoursitoidays
,5. SynthesisiPhasei(Siphase):i-DNAireplicates
-ResultsiinitheiformationiofiidenticalipairsiofiDNAi(chromatids)
-whichiareiattachediaititheicentromere
-lastsi2-10ihours
,6. MitoticiPhasei(Miphase):i-
Replicatedichromosomesiareialigned,iseparated,andimoveiintoi
2inew,iidenticalidaughtericells
-takesiabouti30-60iminutes
, 7. Majoripointsioficelliregulationiareientryiandiexitifrom:i-G1icheckpoint
-SiPhase
-G2icheckpoint
-Miphase
8. RestrictioniPoint:i-
Theitransitionifromitheirestingiphaseiintoianiactively
dividingiphasei(G0-G1)iisiaipointiwhereicellularitransformationicanioccur
-
Duringithisitime,icellsipassithroughiaitransitioniphaseiknowniasiairestrictioni
point
-
ExtracellularigrowthifactorsitriggerireentryiintoiG1,iandiGFiareirequireditoi
sendtheicellsipastitheirestrictionipoint,ioritheipointiofinoireturn
9. G0iPhasei(restingiphase):i-
Afterimitosis,icellsimayienteribackiintoitheiG1phaseior
goiintoiairestingiphase,iknowniasiG0
-MosticellsiinitheihumanibodyiresideiiniG0
10. -Exceptionsitoithisiareithoseithatiarei(RestingiiniG0iphase):i-
Exceptionstoithisiareithoseithatiareimetabollicallyiactive,isuchias
-granulocytes
-anditheiepitheliumiofitheiGIitract
11. CelliCyclingiTime:iAmountiofitimeifromimitosisitoimitosis
12. Cellicycleivideoiand
image:ihttp://highered.mheducation.com/sites/0072495855/st
udent_view0/chap-iter2/animation