BiologBiologyy

CH.CH. 88

Cell Cell DivisionDivision

CH. 8 Cell DivisionCH. 8 Cell DivisionI.I. Cell Growth:Cell Growth:I.I. Cell Growth:Cell Growth:

A. Growth: - increase in

size and

number of cells

B.B. Rate of Cell Growth:Rate of Cell Growth:B.B. Rate of Cell Growth:Rate of Cell Growth:- varies among cells- bacteria are the

fastest~ 20 min.

Binary FissionBinary Fission - - BacteriaBacteria

Binary FissionBinary Fission - - BacteriaBacteria

DNA replicated

Membrane added

Binary Fission - Bacteria

Binary Fission - Bacteriaconstriction

fission

- in humans:- skin cell reproduce quickly- nerve cells reproduce very slowly

Human kidney cells dividing

C.Controls of Cell GrowthC.Controls of Cell Growth

1. External (Environment):- food, temperature, oxygen,

disease, pollution, etc.

2. Internal (Heredity):- DNA, nucleus

Surface AreaSurface Area :: Volume Volume RatioRatio

Surface AreaSurface Area :: Volume Volume RatioRatio

The Size of Cells and Their Components

II. Cancer:II. Cancer:- disease in which cells

have lost the ability to control their own growth

Cervical Cancer Cell Dividing

A. Characteristics of Cancer Cells:

A. Characteristics of Cancer Cells:1. Rapid cell division2. Undifferentiated cells3. Metastasis:

- cells don't stick together and can move

elsewhere

Undifferentiated Cancer Cells

Undifferentiated Cancer Cells

MetastasisMetastasis

B.B. Causes of Cancer:Causes of Cancer:B.B. Causes of Cancer:Causes of Cancer:- genes controlling cell division have

mutated (changed)1.Carcinogens:

- cancer causing agents- nicotine, asbestos, PCB's, etc.

2.Radiation:- UV (sunlight), X-rays, radon, etc.

3.Some viruses4.Hereditary factor

Melanoma:

Early Signs

Melanoma:

Early Signs

III. Cell Division:III. Cell Division:- Mitosis:

division of the nucleus into 2 identical nuclei

- Cytokinesis:division of the cytoplasm to form 2 daughter cells

Mitotic cell Mitotic cell divisiondivision

Mitotic cell Mitotic cell division &division &

DifferentiatiDifferentiationon

FunctionFunctions of s of

MitosisMitosis

TissuesTissues

OrgansOrgans

FertilizeFertilized eggd egg

(zygote)(zygote)Multicell Multicell

stagestage

Asexual Reproduction by Asexual Reproduction by MitosisMitosis

New IndividualsNew Individuals

Asexual Reproduction by Asexual Reproduction by MitosisMitosisBudding

Nucleus divides by mitosis

Bud forms on cell

A. Chromosomes:A. Chromosomes:- made of DNA

and protein- stores

genetic information (genes)

Chromosome

Chromatin

DNAdouble helix

1.1. Chromatin:Chromatin:1.1. Chromatin:Chromatin:- active form of

chromosomes- long, thin strands of DNA

and proteinChromatin

2.Chromatid:2.Chromatid:- one of 2 replicated

halves of chromosomes

- Centromere: point of attachment of 2 sister chromatids

Human Chromosomes

Human Chromosomes

B. The Cell Cycle:B. The Cell Cycle:- 3 parts1. Interphase2.Mitosis3.Cytokinesis

Usually overlap

The Cell Cycl

e

The Cell Cycl

etelophase

metaphase

anaphase

cell

div

isio

n

GG00: :

nondividingnondividing

interphaseinterphase

S: S: Synthesis Synthesis

of DNAof DNA

GG11: Growth: Growth

GG22: Growth: Growth

prophase

cytokinesis

Mit

osi

s

C.C. Interphase:Interphase:C.C. Interphase:Interphase:- period of time between cell

division- takes up 80 - 90% of a cell's life- normal cell activity and growth

NucleusNucleus

ChromatChromatinin

Nuclear Nuclear MembraMembranene

C. Interphase:C. Interphase:- period of time between cell

division- takes up 80 - 90% of a cell's life- normal cell activity and growth1. Cell growth2. DNA replication3. Synthesis of

organelles and centrioles

D.D.Mitosis:Mitosis:D.D.Mitosis:Mitosis:- 4 stages (P, M, A, T)

ProphaseProphase

MetaphaseMetaphase

AnaphaseAnaphase

TelophaseTelophase

1.1. ProphaseProphase1.1. ProphaseProphase- first and longest stagea. Chromatin condenses to form

chromosomesb. Centrioles move to

opposite ends of the cell- animal cells

only

c. Spindle fibers form- protein fibers that aid in

movement of chromosomesd.Nuclear membrane and

nucleolus disappear

2.2. MetaphaseMetaphase2.2. MetaphaseMetaphase- second and shortest stage

- chromosomes line up along the middle of the cell

3. Anaphase3. Anaphase- centromeres split

and chromosomes move apart to opposite sides of the cell

4.4. TelophaseTelophase4.4. TelophaseTelophase- last stage - "reverse" of prophasea. Chromosomes revert

to chromatinb. Spindle fibers

disappearc. Nuclear membrane

and nucleolus reform

E.E. Cytokinesis:Cytokinesis:E.E. Cytokinesis:Cytokinesis:1.Animal Cells

- Cell membrane pinches in forming 2

daughter cells

2. Plant Cells2. Plant Cells- Cell plate forms between 2

daughter cells

Cell plate

Which stage of Which stage of mitosis?mitosis?

Early AnaphaseEarly Anaphase

Which stage of Which stage of mitosis?mitosis?

ProphaseProphase

Which stage of Which stage of mitosis?mitosis?

MetaphaseMetaphase

Which stage of Which stage of mitosis?mitosis?

TelophaseTelophase

Which stages of Which stages of mitosis?mitosis?

ProphaseProphase

InterphaseInterphase

Which stage of Which stage of mitosis?mitosis?

MetaphasMetaphasee

Which stage of Which stage of mitosis?mitosis?

ProphaseProphase

Which stage of Which stage of mitosis?mitosis?

TelophaseTelophase

Which stage of Which stage of mitosis?mitosis?

AnaphaseAnaphase

Which stage of Which stage of mitosis?mitosis?

InterphaseInterphase

The EndThe End