The Cell CycleThe Cell Cycle

Interphase, Mitosis,and Interphase, Mitosis,and CytokinesisCytokinesis

The Cell CycleThe Cell Cycle

Cell Theory: all cells come from pre-Cell Theory: all cells come from pre-existing cellsexisting cells

Prokaryotes: Divide by binary fissionProkaryotes: Divide by binary fissionEukaryotes: Divide by mitosis or meiosisEukaryotes: Divide by mitosis or meiosis

Mitosis: Replication of somatic cells (body Mitosis: Replication of somatic cells (body cells)cells)

Meiosis: Division of germ cells (sex cells)Meiosis: Division of germ cells (sex cells)

The Cell CycleThe Cell Cycle

InterphaseInterphaseNormal cell functions and preparation for Normal cell functions and preparation for

division division MitosisMitosis

Separation of chromosomesSeparation of chromosomesCytokinesisCytokinesis

Division of cytoplasm and cell membraneDivision of cytoplasm and cell membrane

The Cell CycleThe Cell Cycle

GG11: First Growth Phase: First Growth Phase

G stands for GapG stands for GapNormal cell function such as metabolism, Normal cell function such as metabolism,

protein synthesis, and growthprotein synthesis, and growthTypically represents the majority of cell Typically represents the majority of cell

cyclecycleChromosomes are Chromosomes are not replicatednot replicatedGG00: resting phase, no growth or division.: resting phase, no growth or division.

S: Synthesis PhaseS: Synthesis Phase

Relatively short period of timeRelatively short period of timeDNA chromosomes are replicated within DNA chromosomes are replicated within

the nucleusthe nucleusChromosomes are uncondensed and not Chromosomes are uncondensed and not

clearly visibleclearly visibleReplicated pairs of chromosomes are Replicated pairs of chromosomes are

connected at DNA region called connected at DNA region called centromerecentromere

Sister Sister ChromatidsChromatids

Two identical DNA Two identical DNA moleculesmolecules

Attached together at Attached together at the DNA sequence the DNA sequence called centromerecalled centromere

G2: Second Growth PhaseG2: Second Growth Phase

G stands for GapG stands for GapNormal cell function and cell growth Normal cell function and cell growth

continuecontinueOrganelles replicate in final preparation to Organelles replicate in final preparation to

cell divisioncell division

MitosisMitosis

Division of cell nucleus into two nucleiDivision of cell nucleus into two nuclei4 phases4 phases

ProphaseProphaseMetaphaseMetaphaseAnaphaseAnaphaseTelophaseTelophase

MitosisMitosis

ProphaseProphase Chromatin condenses Chromatin condenses

into well defined into well defined chromosomeschromosomes

Nuclear envelope Nuclear envelope dissolvesdissolves

Replicated centrioles Replicated centrioles separate across cellseparate across cell

Spindle apparatus formsSpindle apparatus forms

Spindle ApparatusSpindle ApparatusMicrotubules generated from centriole Microtubules generated from centriole

pair extend across cell and attach to pair extend across cell and attach to proteins at chromatid centrosomeproteins at chromatid centrosome

Centrosome = Centriole PairCentrosome = Centriole Pair

MetaphaseMetaphase

Chromatids are pulled Chromatids are pulled between centrosomesbetween centrosomes

Aligned across Aligned across equator of cellequator of cell

Midline of cell is Midline of cell is called metaphase called metaphase plateplate

AnaphaseAnaphase

Microtubules attached Microtubules attached to chromatids shortento chromatids shorten

Chromatids are pulled Chromatids are pulled apartapart

Chromosomes Chromosomes separate to poles of separate to poles of cellcell

TelophaseTelophase

Non-kinetochore Non-kinetochore microtubules continue microtubules continue to length to length

Nuclear envelope Nuclear envelope reforms at each polereforms at each pole

Chromosomes unfold Chromosomes unfold back to chromatinback to chromatin

CytokinesisCytokinesis

Cytoplasm is divided Cytoplasm is divided between two new cellsbetween two new cells

In animal cells plasma In animal cells plasma membrane pinches membrane pinches closeclose

In plant cells cell wall is In plant cells cell wall is constructed between constructed between nucleinuclei

CancerCancer

When cells lose control When cells lose control of the cell cycle they of the cell cycle they become cancerousbecome cancerous

A tumor is a mass of A tumor is a mass of cells that cannot stop cells that cannot stop dividingdividing

Can occur in any organ Can occur in any organ or tissueor tissue

Animations & VideosAnimations & Videos

Basic MitosisBasic MitosisCondensation of ChromatinCondensation of ChromatinCancer DocumentaryCancer Documentary