Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Lesson Overview 10.1 Cell Growth, Division, and Reproduction

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Limits to Cell Size As cell grows, it is too big for DNA to take care of (information overload) and it can’t move materials fast enough Ratio of surface area to volume key to cell division

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Division of the Cell Before a cell gets too big, it divides into two new “daughter” cells in a process called cell division Before cell division, the cell copies all of its DNA so each new cell gets complete set of “directions”

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Cell Division and Reproduction Asexual vs. Sexual Reproduction Asexual reproduction: production of genetically identical offspring from a single parent; cell division = new organism; ex. binary fission, budding Sexual reproduction: offspring inherit some of their genetic information from each parent; fusion of two cells make offspring; cell division = growth n/preview.weml

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Comparing Sexual and Asexual Reproduction

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Lesson Overview 10.2 The Process of Cell Division Fmg Fmg hill.com/sites/ /student_view0/ch apter2/animation__how_the_cell_cycle_work s.html hill.com/sites/ /student_view0/ch apter2/animation__how_the_cell_cycle_work s.html

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction The genetic information (DNA) that is passed on from one generation of cells to the next is carried by chromosomes Cells of every organism have a specific number of chromosomes (human = ??) Chromosomes

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Prokaryotic Chromosomes Prokaryotic cells chromosomes found in cytosol Most prokaryotes contain a single, circular DNA molecule, or chromosome

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction The Cell Cycle During the cell cycle: the cell grows it prepares for division it divides to form two daughter cells

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Binary fission is a form of asexual reproduction during which two genetically identical cells are produced. For example, bacteria reproduce by binary fission The Prokaryotic Cell Cycle

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction The Eukaryotic Cell Cycle 4 phases of the cell cycle: G 1 – cell increases in size S – DNA replicated G 2 – makes organelles and molecules M – mitosis (nucelar division) and cytokinesis Interphase: is the time between cell divisions

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Important Cell Structures Involved in Mitosis Chromatid – each strand of a duplicated chromosome Centromere – the area where each pair of chromatids is joined Centrioles – tiny structures located in the cytoplasm of animal cells that help organize the spindle Spindle – a fanlike microtubule structure that helps separate the chromatids

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Mitosis The 4 phases of mitosis: 1. Prophase 2. Metaphase 3. Anaphase 4. Telophase

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Prophase chromosomes condense, nuclear envelope breaks down

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Metaphase chromosomes line-up at equator of cell

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Anaphase chromatids separate, move to opposite sides of cell

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Telophase nuclear envelope reforms around chromatin; forming 2 nuclei verbio3/full/content/ch9/animations.asp

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Cytokinesis is the division of the cytoplasm; it completes cell division The process of cytokinesis is different in animal and plant cells Animal cells – cleavage Plant cells – cell plate Cytokinesis

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Lesson Overview 10.3 Regulating the Cell Cycle

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Controls on Cell Division The cell cycle is controlled by regulatory proteins both inside and outside the cell The controls on cell growth and division can be turned on and off

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction The Discovery of Cyclins Cyclins are a family of proteins that regulate the timing of the cell cycle in eukaryotic cells

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Regulatory Proteins Internal regulators are proteins that respond to events inside a cell External regulators (ex. growth factors) are proteins that respond to events outside the cell

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Apoptosis Apoptosis is a process of programmed cell death. Apoptosis plays a role in development by shaping the structure of tissues and organs in plants and animals

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction Cancer: Uncontrolled Cell Growth Cancer is a disorder in which body cells lose the ability to control cell growth Cancer cells divide uncontrollably to form a mass of cells called a tumor activities/activity2_animations.htm

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction TUMORS: benign malignant

Lesson Overview Lesson Overview Cell Growth, Division, and Reproduction What Causes Cancer? Cancers are caused by defects in genes that regulate cell growth and division. Some sources of gene defects are smoking tobacco, radiation exposure, defective genes (p53), and viral infection