Cell Division Cell Division Mitosis Mitosis Reasons for Mitosis - - PowerPoint PPT Presentation

Cell Division Cell Division

Mitosis Mitosis

Reasons for Mitosis Reasons for Mitosis

There are three main reasons There are three main reasons

A.

• A. growth

growth B.

• B. repair/healing

repair/healing C.

• C. asexual reproduction

asexual reproduction

Cell Division by mitosis Cell Division by mitosis

• Some cells divide

Some cells divide constantly: cells in the constantly: cells in the embryo, skin cells, gut embryo, skin cells, gut lining cells, etc. lining cells, etc.

Epithelial Cell Intestinal Cell 7 week old embryo

Cell Division Cell Division

• Other cells divide rarely or

Other cells divide rarely or never. never.

Brain Cell – Nerve cell Spinal Cord Cell- Nerve cell Cardiac Cell (Heart Muscle)

Cell Division Cell Division

• 2 kinds of cell division:

2 kinds of cell division:

• 1. Mitosis: division of somatic cells
• 1. Mitosis: division of somatic cells
• 2. Meiosis: creation of new sex cells
• 2. Meiosis: creation of new sex cells

Sperm cells Human egg cell Pancreatic cells

Cell Division Vocabulary Cell Division Vocabulary

• Somatic cell

Somatic cell – a body cell; a cell whose – a body cell; a cell whose genes will not be passed on to future genes will not be passed on to future generations. generations.

• Germ cell

Germ cell - a cell that is destined to

• a cell that is destined to

become a gamete (egg or sperm); a cell become a gamete (egg or sperm); a cell whose genes can be passed on to whose genes can be passed on to future generations future generations

Cell Division Vocabulary Cell Division Vocabulary

• diploid (2N)

diploid (2N) – a cell with 2 chromosome – a cell with 2 chromosome sets in each of its cells; all body sets in each of its cells; all body (somatic) cells (somatic) cells

• haploid (N)

haploid (N) – a cell with 1 chromosome – a cell with 1 chromosome set in each of its cells; all gametes set in each of its cells; all gametes (sperm, eggs) (sperm, eggs)

• A

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• a

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r ema ins t he sa me C hr

• mosome number

r ema ins t he sa me

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he DN A r ema ins ident ica l l y t he sa me T he DN A r ema ins ident ica l l y t he sa me

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Characteristics of Characteristics of Mitosis Mitosis

Cell Cycle Cell Cycle

• A typical cell goes

A typical cell goes through a process through a process

• f growth,
• f growth,

development, and development, and reproduction called reproduction called the cell cycle. the cell cycle.

• Most of the cycle is

Most of the cycle is called interphase. called interphase.

INTERPHASE

Cell Cycle Cell Cycle

• The longest

The longest phase in the phase in the cell cycle is cell cycle is interphase. interphase.

• The 3 stages of

The 3 stages of interphase are interphase are called G called G 1

1, S,

, S, and G and G 2

2.

.

Cell Division Cell Division

• All living cells come from other living

All living cells come from other living cells. cells.

• During mitosis, the nucleus of the cell

During mitosis, the nucleus of the cell divides, forming two nuclei with divides, forming two nuclei with identical genetic information. identical genetic information.

Mitosis Mitosis

• Mitosis produces

Mitosis produces two genetically two genetically identical cells. identical cells.

• Mitosis is referred

Mitosis is referred to in the following to in the following stages: prophase, stages: prophase, metaphase, metaphase, anaphase, and anaphase, and telophase. telophase.

Prophase Prophase

• In prophase, the cell begins the process of

In prophase, the cell begins the process of division. division.

• The chromosomes condense.

The chromosomes condense.

chromatin duplicated chromosom e

Prophase Prophase

• Nuclear envelope disappears.

Nuclear envelope disappears.

Prophase Prophase

• Centrioles

Centrioles migrate to migrate to

• pposite poles of
• pposite poles of

the cell. the cell.

• Asters and

Asters and spindle fibers spindle fibers form. form.

Aster and the mitotic apparatus in an animal cell

Draw Prophase Draw Prophase

Prophase Prophase

Aster Sister chromatids Centromere Centriole Spindle fibers

Metaphase Metaphase

• The

The chromosomes chromosomes line up at the line up at the equator of the cell equator of the cell (metaphase plate), (metaphase plate), with the centrioles with the centrioles at opposite ends at opposite ends and the spindle and the spindle fibers attached to fibers attached to the centromeres. the centromeres.

Centriole Centriole Spindle fibers Metaphase plate

Draw Metaphase Draw Metaphase

Anaphase Anaphase

• In anaphase, the

In anaphase, the centromeres divide. centromeres divide.

• At this point, each

At this point, each chromosome goes chromosome goes from having 2 sister from having 2 sister chromatids to being chromatids to being 2 separate 2 separate chromosomes chromosomes

Anaphase Anaphase

• The spindle fibers

The spindle fibers contract and the contract and the chromosomes are chromosomes are pulled to opposite pulled to opposite poles. poles.

Draw Anaphase Draw Anaphase

Telophase Telophase

• In telophase the

In telophase the nucleus actually nucleus actually divides. divides.

• The chromosomes are

The chromosomes are at the poles of the cell. at the poles of the cell.

• The nuclear envelope

The nuclear envelope re-forms around the re-forms around the two sets of two sets of chromosomes. chromosomes.

Draw Telophase Draw Telophase

Cytokinesis Cytokinesis

• The division of the

The division of the cytoplasm. cytoplasm.

• In animal cells, a

In animal cells, a Cleavage Furrow Cleavage Furrow forms and forms and separates Daughter separates Daughter Cells Cells

Cleavage furrow in a dividing frog cell.

Cytokinesis Cytokinesis

• In plant cells, a Cell Plate

In plant cells, a Cell Plate forms and separates forms and separates Daughter Cells. Daughter Cells.

Cell Plate forming

ANIMAL VS. PLANT MITOSIS ANIMAL VS. PLANT MITOSIS

• ANIMAL CELL

ANIMAL CELL

• Centriole and

Centriole and aster present aster present

• Daughter cells

Daughter cells separated by separated by cleavage furrow cleavage furrow

• PLANT CELL

PLANT CELL

• No visible

No visible centriole or centriole or aster aster

• Daughter cells

Daughter cells separated by separated by cell plate cell plate

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1 2 3 4 5

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Prophase 2 3 4 5

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Prophase Metaphase 3 4 5

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Prophase Metaphase Anaphase 4 5

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Prophase Metaphase Anaphase Telophase 5

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Prophase Metaphase Anaphase Telophase Cytokinesis

• P

ha ses of cel l cy cl e- IP M A T C P ha ses of cel l cy cl e- IP M A T C

Interphase Cytokinesis

• Phases of cell cycle - IPMATC

Phases of cell cycle - IPMATC

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