Cell DivisionCell Division

B-2.6 Summarize the characteristics of the cell B-2.6 Summarize the characteristics of the cell cycle: interphase (called G1, S, G2); the phases of cycle: interphase (called G1, S, G2); the phases of mitosis (called prophase, metaphase, anaphase, mitosis (called prophase, metaphase, anaphase, and telophase); and plant and animal cytokinesis.and telophase); and plant and animal cytokinesis.

The Cell CycleThe Cell Cycle

Draw a large circle on your pageDraw a large circle on your page Divide into 4 parts like this:Divide into 4 parts like this:

Interphase:

G1 Phase (Growth)

S Phase (Synthesis)

G2 Phase (Growth)

M Phase (Mitosis)

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

G1

S

G2

P

MA TC

G0

The Cell CycleThe Cell Cycle

The Cell CycleThe Cell Cycle

INTERPHASEINTERPHASE

G1 Phase– Cell grows, makes proteins

S Phase– DNA replicates (synthesizes)

G2 Phase– Growing, getting ready for cell

division

INTERPHASEINTERPHASE

M Phase: MITOSISM Phase: MITOSIS

Prophase– Chromatin condenses into Chromatin condenses into

chromosomeschromosomes, becomes visible, becomes visible– Nuclear membraneNuclear membrane disappears disappears– CentriolesCentrioles separate to opposite poles separate to opposite poles– Spindle fibersSpindle fibers form, grow toward center form, grow toward center

Longest phase (50-60% of mitosis)Longest phase (50-60% of mitosis)

Prophase:Prophase:

A little about CHROMOSOMES…

In Interphase, DNA in long thin threads, called CHROMATIN. Here, in S phase, they duplicate (replicate, synthesize)

As Prophase begins, CHROMATIN winds up (condenses) into Chromosomes.Made of two sister Chromatids, joined at the

Centromere.

A duplicated chromosome:

This is interphase’s chromatin, long thin strands of proteins and DNA. Only later in mitosis’ beginning, Prophase, will this condense and coil up into the classic looking X shaped structures, termed chromosomes.

Coiled chromosomes

M Phase: MITOSISM Phase: MITOSIS

Metaphase– Chromosomes line up at cell’s

equator– Spindle fibers connect to chrom.

Shortest phase of mitosis

Metaphase:Metaphase:

M Phase: MITOSISM Phase: MITOSIS

Anaphase– Centromeres that join the sister

chromatids split– Sister chromatids separate,

becoming individual chrom.– They now move to opposites sides of

cell

Anaphase:Anaphase:

M Phase: MITOSISM Phase: MITOSIS

Telophase– Chromosomes uncoil, disappear– Nuclear envelope reforms– Spindle fibers break down– Cytokinesis begins

Telophase:Telophase:

M Phase: MITOSISM Phase: MITOSIS

Cytokinesis: Cytoplasm division– In animals, cleavage furrow pinches

cell in two.

– In plants, a cell plate forms, becoming the new wall.

Cytokinesis: animalCytokinesis: animal

Cleavage furrow

Cytokinesis: plantsCytokinesis: plants

M Phase: MITOSISM Phase: MITOSIS

PracticePractice