Mitosis Body Cell Reproduction Cell Cycle Cell cycle

Mitosis Body Cell Reproduction

Cell Cycle Cell cycle- The sequence of stages through which a cell passes between one cell division and the next. (The cycle begin growth and division. ) 2 2

Cell Cycle The cell spends most of its time in interphase. Stage 1 - G 1 - cell grows, organelles may begin to duplicate, cytoplasm increases and protein synthesis occurs Stage 2 - S- DNA replicates Stage 3 - G 2 -cell continues to grow, organelles double, and microtubules synthesize

Mitosis is a type of cell division that generates two identical daughter cells. Mitosis occurs in body cells. Body cells are called somatic cells.

Mitosis is a part of the cell cycle. It has 4 phases. (PMAT) Human cells have 46 chromosomes or 23 pairs. This is called a diploid number. (2 N) Mitosis requires only one parent asexual reproduction.

How do little elephants grow up to be BIG elephants?

Why do animals shed their skin?

Three reasons why cells reproduce by mitosis: 1. Growth 2. Repair 3. Replacement Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun. Cell that reproduce by asexual reproduction reproduce constantly.

Animated Mitosis Cycle http: //www. cellsalive. com/mitosis. htm • Interphase • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis

Interphase occurs before mitosis begins Chromosomes are copied (# doubles) • Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase • Nucleus CELL MEMBRANE Cytoplasm

Interphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Prophase 1 st step in Mitosis begins (cell begins to divide) • Centrioles (or poles) appear and begin to move to opposite ends of the cell. • Spindle fibers form between the poles. • Sister chromatids Centrioles Spindle fibers

Prophase Animal Cell Plant Cell Spindle fibers Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Metaphase 2 nd step in Mitosis • Chromatids (or pairs of chromosomes) attach to the spindle fibers. Centrioles Spindle fibers

Metaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Anaphase 3 rd step in Mitosis • Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Centrioles Spindle fibers

Anaphase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Telophase 4 th step in Mitosis Two new nuclei form. • Chromosomes appear as chromatin (threads rather than rods). • Mitosis ends. • Nuclei Chromatin Nuclei

Telophase Animal Cell Plant Cell Photographs from: http: //www. bioweb. uncc. edu/biol 1110/Stages. htm

Cytokinesis occurs after mitosis • Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase

Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase

Cell Cycle 24

Questions Sec 1 1. What is a gene? 2. What are chromosomes? 3. Describe a prokaryotic chromosome. 4. Describe a eukaryotic chromosome. 5. What is chromatin? 6. What is a chromatid? 7. What is a centromere?

Questions Sec. 2 and 3 1. Define Cell Cycle. 1. 2. What is mitosis? 3. What is cytokinesis? 4. What is a spindle fiber?

Questions Sec. 2 and 3 1. Define Cell Cycle. 1. 2. What is mitosis? 3. What is cytokinesis? 4. What is a spindle fiber?

CHROM…words Chromatin – uncoiled DNA + proteins (threads) Chromosome – coiled DNA + proteins (Looks like an X) Chromatid – only half of a chromosome Sister chromatids – Two chromatids joined together, by a centromere, to form a chromosome

Mitosis Animation http: //www. cellsalive. com/mitosis. htm