Mitosis and Meiosis Mitosis Cell Division n In

Mitosis: Cell Division n In each human cell there are 23 unique chromosomes each

Mitosis n In order to keep the same genetic information cells undergo a process

A) Cell Cycle n The life cycle of a cell has 2 portions: Interphase

A) Cell Cycle n Interphase has 3 steps: ¡ ¡ ¡ G 1 -

B) Mitosis n Mitosis is divided into 4 steps: ¡ ¡ n Prophase Metaphase

Mitosis: Prophase n n n The nuclear envelop breaks down Chromatin condenses into chromosomes

Mitosis: Metaphase n n The individual chromosomes line up at the center metaphase plate

B) Mitosis: Anaphase n The centrioles pull on the spindles and separate the chromatids

B) Mitosis: Telophase n n n The chromatids are now in opposite ends of

B) Mitosis: Cytokinesis n In animals proteins pinch off the center of the cell

C) Meiosis n n n In sex cells cell division is different. The process

C) Meiosis n n The process of meiosis is called a reduction division. There

C) Meiosis n The first round of meiosis has the following steps: Prophase I,

C) Meiosis n Differences: ¡ ¡ ¡ During Prophase I homologous chromosomes pair up

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Mitosis and Meiosis

Mitosis: Cell Division n In each human cell there are 23 unique chromosomes each containing thousands of genes. Most cells in the human body have 2 copies of every chromosome These cells are called diploid (2 n).

Mitosis n In order to keep the same genetic information cells undergo a process of division that ensures the same information is passed from parent to offspring.

A) Cell Cycle

A) Cell Cycle n The life cycle of a cell has 2 portions: Interphase and Mitosis. ¡ Interphase is the normal condition of a cell. During this time the cell does its job and prepares for division. ¡ Mitosis is the process of division.

A) Cell Cycle n Interphase has 3 steps: ¡ ¡ ¡ G 1 - The cell produces proteins and performs its normal functions in the body. S – DNA inside the nucleus replicates. G 2 – The cell resumes growth/function and readies for division.

B) Mitosis n Mitosis is divided into 4 steps: ¡ ¡ n Prophase Metaphase Anaphase Telophase After Mitosis Cytokinesis occurs, which is the division of the cytoplasm.

Mitosis: Prophase n n n The nuclear envelop breaks down Chromatin condenses into chromosomes (Xs) Spindle fibers begin migrating to opposite ends.

Mitosis: Metaphase n n The individual chromosomes line up at the center metaphase plate Centrioles and spindles are at opposite ends of the cell and connected to every pair of chromosomes at the centromere.

B) Mitosis: Anaphase n The centrioles pull on the spindles and separate the chromatids to opposite sides.

B) Mitosis: Telophase n n n The chromatids are now in opposite ends of the cell and they begin to decondense. Nuclear membrane begins to reform. Spindles break down.

B) Mitosis: Cytokinesis n In animals proteins pinch off the center of the cell into 2 each parts, seperating the cytoplasm. n. In plants the Golgi synthesizes a new cell wall along the metaphase plate, creating 2 separate cells.

C) Meiosis n n n In sex cells cell division is different. The process must half the number of chomosomes in each cell. This allows for fertilization to recreate the complete number of chromosomes.

C) Meiosis n n The process of meiosis is called a reduction division. There are 2 rounds of division with some slight differences.

C) Meiosis

C) Meiosis n The first round of meiosis has the following steps: Prophase I, Metaphase I, Anaphase I, and Telophase I. n The second round of division is made up of: Prophase 2, Metaphase II, Anaphase 2, and Telophase 2.

C) Meiosis n Differences: ¡ ¡ ¡ During Prophase I homologous chromosomes pair up at the metaphase plate! There is NO DNA duplication between Meiosis I and II, so the DNA never has a chance to double. The end result is 4 haploid cells instead of 2 diploid cells.

C) Meiosis