Biology Chap8 Notes

Destiny Cobb Biology Chapter 8 pgs.200-225 Main Idea Section 8.1 Cellular Transport

Notes/Vocabulary • Osmosis is the diffusion of water through a selectively permeable membrane. • Passive Transport moves a substance with the concentration gradient and requires no energy from the cell. • Active transport moves materials against the concentration gradient and requires energy to overcome the opposite flow of materials with the concentration gradient. • Large particles may enter a cell by endocytosis and leave by exocytosis.

Osmosis: Diffusion of Water Osmosis- diffusion of water across a selectively permeable membrane depending on the concentration of solutes on either side of the membrane -Isotonic solution- in cells, a solution in which the concentration of dissolved substance in the solution is the same as the concentration of dissolved substances inside the cell -Hypotonic Solution- in cells, the solution in which the concentration of dissolved substances is lower in the solution outside the cell than the concentration inside the cell; causes cells to swell, and possibly burst as water enters the cell -Hypertonic Solution- in cells, the solution in which the concentration of dissolved substances outside the cell is higher the concentration inside the cell; causes a cell to shrink as water leaves the cell

Passive Transport Passive Transport- movement of cell particles across cell membranes by diffusion of osmosis; the cell uses no energy to move particles across the membrane -Facilitated Diffusion- passive transport of materials across a plasma membrane by transport proteins embedded in plasma membrane

Active Transport

Destiny Cobb Biology Chapter 8 pgs.200-225 Active Transport- energy-expending process by which cells transport materials across the cell membrane against a concentration gradient Transport of Large Particles: Endocytosis- active transport process where a cell engulfs materials with a portion of the cell’s plasma membrane and releases the contents inside the cell Exocytosis- active transport process by which materials are secreted or expelled from a cell • Cell size is limited largely by the diffusion rate of a Section 8.2 materials into and out of the cell, the amount of DNA Cell Growth and available to program the cell’s metabolism, and the Reproduction cell’s surface area-to-volume ratio. • The life cycle of a cells divided into two genetic periods: a period of active growth and metabolism, known as interphase, and a period of cell division known as mitosis. • Mitosis is divided into 4 phases: prophase, metaphase, anaphase, and telophase. • The cells of most multicellular organisms are Section 8.2 organized into tissues, organs, and organ system. Cell Growth and Reproduction Cell Reproduction (continued) Chromosome- cell structures that carry the genetic material that is copied and passed from generation to generation of cells Chromatin- long, tangled strands of DNA found in the eukaryotic cell nucleus during interphase Cell Cycle Cell Cycle- continuous sequence of growth (interphase) and division (mitosis) in a cell Interphase- cell growth phase were a cell increases in size, carries on metabolism, and duplicates chromosomes prior to division Mitosis- period of nuclear cell division in which two daughter cells are formed, each containing a complete set of chromosomes The Phases of Mitosis: 1) Prophase- 1st and longest phase of mitosis where chromatin coils into visible chromosomes

Destiny Cobb Biology Chapter 8 pgs.200-225 A) Sister Chromatids- identical halves of a duplicated parent chromosome formed during the prophase stage of mitosis; the halves are held together by a centromeres B) Centromere- cell structure that joins two sister chromatids of a chromosome C) Centriole- in animal cells, a pair of small cylindrical structures composed of microtubules that duplicate during interphase and move to opposite ends of the cell during interphase D)Spindle- cell structures composed of microtubules fibers; form between the centrioles during prophase and shorten during anaphase, pulling apart sister chromatids Section 8.2 Cell Growth and Reproduction (continued)

2) Metaphase- short second phase of mitosis where doubled chromosomes move to the equator of the spindle and chromatids are attached by centromeres to a separate spindle fiber 3) Anaphase- phase of mitosis where the centromeres split and the chromatid pairs of each chromosome are pulled apart by microtubules 4) Telophase- final phase of mitosis during which new cells prepare for their own independent existence Division of the Cytoplasm Cytokinesis- cell process following meiosis or mitosis in which the cell’s cytoplasm divides and separates into new cells Result of Mitosis Tissue- group of cells that work together to perform a specific function Organ- group of 2 or more tissues organized to perform complex activities within an organism Organ System- multiple organs that work together to perform a specific life function

Section 8.3 Control of the Cell Cycle

Destiny Cobb Biology Chapter 8 pgs.200-225 • The cell cycle is controlled by key enzymes that are produced at specific points in the cell cycle. • Cancer is caused by genetic and environmental factors that change the genes that control the cell cycle. • For some types of cancer, research has shown that lifestyle choices like eating a healthy diet and exercising regularly can reduce the incidence of cancer Normal Control of the Cell Cycle Cancer- uncontrolled cell division that may be caused by environmental factors and/or changes in enzyme production in the cell cycle Gene- segment of DNA that controls the protein production and the cell cycle