Cell Cycle and Mitosis

How do cells make more of themselves? They go through the Cell Cycle Remember each cell has the same DNA

What is DNA? DNA is the molecule that has hereditary information Each person’s DNA is different except for identical twins

DNA- a double helix ( twisted ladder)

Cell Cycle Interphase- consists of 90% of the cell cycle 1)G 1 2) S phase 3)G2 M Phase- Mitosis

G1 Cell is growing

S phase Cell is growing DNA is replicated

G 2 Cell is growing

What is a chromosome? When a cell is dividing, DNA winds up tightly and forms chromosomes in the nucleus of the cell. Chromosomes- made of DNA and protein ( chromatin)

How many chromosomes do human have? Humans – 46 Egg ( from female)- 23 Sperm ( from male) 23 Egg + Sperm = Human

Chromosome to Duplicated Chromosome

What is a gene? A specific portion of the DNA code is called a gene, which has genetic information. The genes are contained within the chromosome.

Important Vocabulary Somatic cells (cells of the body) are diploid. This means that each cell has two chromosomes of each type. They are in PAIRS. Gamete cells (egg, sperm) are haploid. This means that each cell has only one of each type of chromosome. Biologists use “2N” to symbolize diploid. Biologists use “1N” to symbolize haploid.

MITOSIS cell division

MITOSIS Start: 1 cell End: 2 identical cells Cell Reproduction: Division of the cell to make new cells. Start: 1 cell End: 2 identical cells

MITOSIS 4 PHASES/STEPS NUCLEUS ONLY

Phases of Mitosis P rophase M etaphase A napahse T elophase

PROPHASE Nuclear membrane disappears. Centrioles move to opposite sides of cell. Chromosomes duplicate

PROPHASE

PROPHASE

METAPHASE Chromatids attach to spindle fibers and line up in MIDDLE of cell.

METAPHASE MILITARY LINE-UP

METAPHASE

ANAPHASE Chromatids Are pulled to opposite sides of the cell.

ANAPHASE AWAY

ANAPHASE

TELOPHASE New nuclear membrane surrounds Chromosomes, which return to chromatin.

TELOPHASE TWO NUCLEI

TELOPHASE

CYTOKINESIS Cytoplasm splits

Differences in Cytokinesis Animal Cell- Cytoplasm pinches in forming a cleavage furrow Plant cell- forms a cell plate

Animal Cell Cytokinesis Cleavage furrow forms

Plant Cell Cytokinesis Cell plate forms between plant cells

CYTOKINESIS

CYTOKINESIS 2 CELLS

Always Changing

CREATION OF 2 NEW IDENTICAL Body CELLS also known as somatic cells WHOLE PROCESS: CREATION OF 2 NEW IDENTICAL Body CELLS also known as somatic cells

Phases of Mitosis 4 phases: Prophase Metaphase Anaphase Telophase Cytokinesis- division of the cytoplasm

Products of Mitosis 2 daughter cells that are Exactly the same