CELL CYCLE

Mitosis

The functions of cell division: Reproduction

The functions of cell division: Growth and development

Eukaryotic Chromosomes

The functions of cell division: Growth and development

Mitosis cell division somatic cellThe form of cell division by which a eukaryotic somatic cell duplicates. Mitosisasexual reproduction.Mitosis is asexual reproduction. Cell divisionCell division is the continuation of life based on the reproduction of cells.

Mitosis 2n=46 Skin Cell 2n=46 two identical daughter cells Skin Cell

The Asexual Reproduction of a Hydra Budding

Somatic Reproduction Somatic Reproduction mitosisMost eukaryotic cells reproduce asexually by mitosis. Somatic cells body cells (like nerve, liver, etc...)Somatic cells are all body cells (like nerve, liver, etc...) except sperm and ova (egg). chromosomesAll somatic cells have the same number of chromosomes.

Cell Cycle Mitosis -prophase -metaphase -anaphase -telophase G1G1 G2G2 S phase interphase

Cell Cycle dividingnon-dividingThe dividing and non-dividing stages in the life of a cell. Phases: 1.Interphase 1.Interphase: growth and DNA replication 2.Prophase 3.Metaphase 4.Anaphase 5.Telophase Mitotic division

Molecular Control of the Cell Cycle at the G 2 Checkpoint

Interphase 90%cell cycleComprises about 90% of the cell cycle. Cellular growthCellular growth: protein synthesis a. protein synthesis metabolic activities b. metabolic activities DNAsynthesis c. DNA synthesis three phasesMade up of three phases: 1. G 1 phase 2. S phase 3. G 2 phase

Interphase 1. G 1 (gap) phase: a. Cellular growth, protein synthesis and metabolic activities. 2. S phase: DNA synthesis/replication a. DNA synthesis/replication takes place. 3.G 2 (gap) phase: a. organelles replicated, chromosomes condense, microtubules assemble M phase b. Preparation for M phase.

Interphase NucleusnucleolusNucleus and nucleolus visible. Nuclear membrane nucleolus cell membrane chromatin

Question: What is a chromosome?What is a chromosome?

Answer: chromosome DNAhistone protein chromatinA chromosome is made up of a DNA - histone protein complex called chromatin. Chromatin chromosomes Chromatin is a long, thin fiber that is folded and coiled to form chromosomes. DNA double helix Histone proteins chromosome

Question: What is a replicated chromosome?What is a replicated chromosome?

Answer: chromosome chromatidssister chromatidsA replicated chromosome consist of two strands of identical chromosomal material called chromatids (sister chromatids). chromatid S phase: chromosomes replicate chromosome centromere

Chromosome Duplication and Distribution During Mitosis

Question: When is a chromatid a chromatid?When is a chromatid a chromatid?

chromatidchromatid sister chromatidcentromereA chromatid is a chromatid as long as it is held in association with a sister chromatid at the centromere. chromatid centromere chromosome Chromatid

Mitotic Phase MitosisMitosis nucleargenetic material a.nuclear division of genetic material. b. prophase-metaphase- anaphase-telophase CytokinesisCytokinesis a.cytoplasmic division a.cytoplasmic division. b.Indicator of telophase.

The stages of mitotic cell division in an animal cell: G 2 phase; prophase; prometaphase

The stages of mitotic cell division in an animal cell: metaphase; anaphase; telophase and cytokinesis.

The Cell Cycle and Mitosis

Prophase Longest phaseLongest phase Nucleolus disappears chromosomes sister chromatidsChromatin material condenses into chromosomes, consisting of two sister chromatids.

Prophase CentriolesCentrioles move apart (not found in plants). Spindle fibers centriolescentromeres by kinetochores.Spindle fibers form and attach from centrioles to centromeres by kinetochores. Nuclear envelope fragments and disappears.

Prophase late prophase early prophase centrioles spindle fibers centromere nuclear envelope disappearing aster fibers

Question: What attaches the spindle fibers to the centromeres?What attaches the spindle fibers to the centromeres?

Answer: Kinetochores sisterchromatidsisterchromatid centromere spindle fiber kinetochores centriole aster fibers

Metaphase Shortest phase Centrioles aster fibersCentrioles are at opposite ends of the cell and attached with aster fibers. Chromosomes metaphase plateequatorial plateChromosomes move to the metaphase plate (equatorial plate - center of cell).

Metaphase metaphase plate centrioles spindle fibers aster fibers

Metaphase

Karyotypes are typically made during metaphase. A method of organizing the chromosomes of a cell in relation to number, size, and type.A method of organizing the chromosomes of a cell in relation to number, size, and type.

Anaphase Centromeres spindle fibersCentromeres uncouple and spindle fibers shorten. Sister chromatidsSister chromatids separate and move apart. chromatids chromosomesAfter separation, chromatids are now considered chromosomes.

Anaphase chromosomesDuring this phase, the cell contains twice the normal number of chromosomes. elongateCell begins to elongate. chromosomesAt the end, there are equal numbers of chromosomes at the poles.

Anaphase sister chromatids No longer sister chromatids, chromosomes now chromosomes centrioles spindle fibers aster fibers

Telophase furrow CytokinesisCleavage furrow develops in animal cells (Cytokinesis begins). Cell plate plantsCell plate develops in plants (no cleavage furrows in plants).Cell plate Cell plate Nucleolus reappears. cell plate

Telophase Nuclear membrane reappears. ChromosomesChromosomes uncoil. karyokinesisIn the end, two genetically identical nuclei (karyokinesis completed) are present.

Telophase cleavage furrow (cytokinesis) nuclear membrane reforming nucleolus reappears

Cytokinesis Cytoplasmic divisionCytoplasmic division Cell plate plantsCell plate complete in plants In the end, two separate daughter cells produced with single nucleus. cell plate

Cytokinesis in Animal and Plant Cells

A Hypothesis for the Evolution of Mitosis microtubules form spindle within nucleus

Bacterial Cell Division (binary fission)

Mitosis in a Plant Cell

Mitosis in an Onion Root

Question: 20 chromosomes chromosomes eachA cell containing 20 chromosomes at the beginning of mitosis would, at its completion, produce cells containing how many chromosomes each?

Answer: 20 chromosomes20 chromosomes

Question: 40 chromatids chromosomes eachA cell containing 40 chromatids at the beginning of mitosis would, at its completion, produce cells containing how many chromosomes each?

Answer: 20 chromosomes20 chromosomes

Density-Dependent Inhibition of Cell Division

The Growth and Metastasis of a Malignant Breast Tumor

Breast Cancer Cell

Mammogram: Normal (left) and Cancerous (rt)

Cancer Cells

Cancer Cells Versus Normal Cells

1)Give two reasons why cells divide. 2) As a cell increases in size, which increases more rapidly, its surface area or its volume?

Draw a chromosome and label the chromatids and centromere. The division of the cytoplasm at the end of mitosis is called: