Cell Reproduction

Cell Reproduction

ChromosomesMitosisMeiosis

ChromosomesMitosisMeiosis

ChromosomesChromosomes

Cell DivisionCell Division

• Cell Division is the process by which cells reproduce.

• information in the cell is contained in genes → genes code for proteins → proteins carry out cellular functions

• Each body cell that results from cell division must have an exact copy ofthe DNA in the original cell.

• Cell Division is the process by which cells reproduce.

• information in the cell is contained in genes → genes code for proteins → proteins carry out cellular functions

• Each body cell that results from cell division must have an exact copy ofthe DNA in the original cell.

Chromosome StructureChromosome Structure

ChromosomeStructure

ChromosomeStructure

Chromosome StructureChromosome Structure

ChromosomeStructure

ChromosomeStructure

Chromosome NumberChromosome Number

KaryotypeKaryotype

Diploid vs. HaploidDiploid vs. Haploid• Diploid (2n): a cell that

contains both chromosomes of a homologous pair• Humans = 46 (somatic cells:

body cells)

• Haploid (n): a cell that has only one chromosome of each homologous pair• Humans = 23 (gametes:

egg and sperm)

• Diploid (2n): a cell that contains both chromosomes of a homologous pair• Humans = 46 (somatic cells:

body cells)

• Haploid (n): a cell that has only one chromosome of each homologous pair• Humans = 23 (gametes:

egg and sperm)

MitosisMitosis

MitosisMitosis• Mitosis: the division of the cell

nucleus in which the chromosomes in the parent cell divide into two identical sets

• In somatic cells (body cells), the number of cells is increased without changing the information contained in the DNA or the amount of DNA in those cells.

• Mitosis: the division of the cell nucleus in which the chromosomes in the parent cell divide into two identical sets

• In somatic cells (body cells), the number of cells is increased without changing the information contained in the DNA or the amount of DNA in those cells.

Binary FissionBinary Fission

• Binary Fission: cellular division of unicellular organisms that produces identical offspring

• Binary Fission: cellular division of unicellular organisms that produces identical offspring

Cell CycleCell Cycle

OverviewOverview

Important StructuresImportant Structures

Asters

Centrioles

Polar Fibers

Kinetechore Fibers

Equator

Kinetechore

Mitosis in AnimalsMitosis in Animals

G1

• Normal growing cell

• DNA = chromatin

• Organelles are doubling (not shown)

G1

• Normal growing cell

• DNA = chromatin

• Organelles are doubling (not shown)

S• DNA

Replication

G2

• Final Preparation for Mitosis

S• DNA

Replication

G2

• Final Preparation for Mitosis

Prophase• Chromosom

e formation• Nucleus and

nucleolus disappear

• Centrioles begin forming spindle fibers

Prophase• Chromosom

e formation• Nucleus and

nucleolus disappear

• Centrioles begin forming spindle fibers

Cell Membrane

Nucleus

Nucleolus

Telophase• Nucleus and

nucleolus reappear

• Chromatids uncoil back to chromatin

• Beginning of cell division

Telophase• Nucleus and

nucleolus reappear

• Chromatids uncoil back to chromatin

• Beginning of cell division

Anaphase• Chromosom

es split into chromatids

• Chromatids move to opposite poles

Anaphase• Chromosom

es split into chromatids

• Chromatids move to opposite poles

Metaphase• Chromosom

es line up along the equator

Metaphase• Chromosom

es line up along the equator

Cytokinesis• Complete cell division results in daughter

cells that are exactly the same as the original

Cytokinesis• Complete cell division results in daughter

cells that are exactly the same as the original

Mitosis in PlantsMitosis in Plants

Cleavage Furrow & Cell PlateCleavage Furrow & Cell Plate

Control of Cell SizeControl of Cell Size

• Cell Size (SA/V)

• Regulatory Checkpoints - Enzymes

• Cell Size (SA/V)

• Regulatory Checkpoints - Enzymes

MeiosisMeiosis

OverviewOverview

MeiosisMeiosis

Genetic RecombinationGenetic Recombination• Genetic Recombination: the

process that results in chromosomes being arranged in many different ways• crossing-over between homologues

or chromatids• homologous pairs separate

independently in meiosis I• sister chromatids separate

independently in meiosis II

• Genetic Recombination: the process that results in chromosomes being arranged in many different ways• crossing-over between homologues

or chromatids• homologous pairs separate

independently in meiosis I• sister chromatids separate

independently in meiosis II

CROSSINGV

ER

CROSSINGV

ER

Independent

Assortment