PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PART B 3 Cells and Tissues

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cell Physiology: Membrane Transport  Membrane transport—movement of substances into and out of the cell  Two methods of transport  Passive transport  No energy is required, uses kinetic energy ( bouncing particles)  Active transport  Cell must provide metabolic energy (ATP)  Membrane transport—movement of substances into and out of the cell  Two methods of transport  Passive transport  No energy is required, uses kinetic energy ( bouncing particles)  Active transport  Cell must provide metabolic energy (ATP)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Selective Permeability  The plasma membrane allows some materials to pass while excluding others

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Diffusion  Movement from high concentration to low concentration, Till particles equally distributed Figure 3.9

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Types of diffusion  Simple diffusion: gases  Small enough particles to pass through membrane pores

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Types of diffusion (continued)  Osmosis—simple diffusion of water  Isotonic Solution: no movement of water, Cell at Equilibrium: homeostasis  Hypertonic Solution: solution outside of cell high in solute, low in water. Water flow out of cell, Cell Shrinks: Plasmolysis, ex dehydration  Hypotonic Solution: solution outside of cell low in solute( pure water) Water flows in to reach balance, Too much- Cell Burst: Cytolysis ex: cut in bath

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Facilitated diffusion  Substances require a protein carrier for passive transport  Transports large substances

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes Figure 3.10b–c

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Filtration  Water and solutes are forced through a membrane by fluid, or hydrostatic pressure  A pressure gradient must exist  Solute-containing fluid is pushed from a high-pressure area to a lower pressure area

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Substances may be too large  Substances may not be able to dissolve in the fat core of the membrane  Substances may have to move against a concentration gradient  ATP is used for transport

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Two common forms of active transport  Solute pumping  Vesicular transport:  Exocytosis  Endocytosis  Phagocytosis  Pinocytosis

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Active transport (solute pumping)  Amino acids, some sugars, and ions are transported by protein carriers called solute pumps  ATP energizes protein carriers  In most cases, substances are moved against concentration gradients

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Vesicular transport  Exocytosis  Moves materials out of the cell  Material is carried in a membranous vesicle  Material is emptied to the outside

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes: Exocytosis Figure 3.12b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Active Transport Processes  Vesicular transport (continued)  Endocytosis  Extracellular substances are engulfed by being enclosed in a membranous vescicle  Types of endocytosis  Phagocytosis—“cell eating”  Pinocytosis—“cell drinking”

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cell Life Cycle  Cells have two major periods  Interphase  Cell grows  Cell carries on metabolic processes  Cell division  Cell replicates itself  Function is to produce more cells for growth and repair processes

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings DNA Replication  Genetic material is duplicated and readies a cell for division into two cells  Occurs toward the end of interphase  DNA uncoils and each side serves as a template

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Events of Cell Division  Mitosis—division of the nucleus  Results in the formation of two daughter nuclei  Cytokinesis—division of the cytoplasm  Begins when mitosis is near completion  Results in the formation of two daughter cells

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Prophase  First part of cell division  Centrioles migrate to the poles to direct assembly of mitotic spindle fibers  DNA appears as double-stranded chromosomes  Nuclear envelope breaks down and disappears

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Metaphase  Chromosomes are aligned in the center of the cell on the metaphase plate

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Anaphase  Chromosomes are pulled apart and toward the opposite ends of the cell  Cell begins to elongate

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Telophase  Chromosomes uncoil to become chromatin  Nuclear envelope reforms around chromatin  Spindles break down and disappear

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis  Cytokinesis  Begins during late anaphase and completes during telophase  A cleavage furrow forms to pinch the cells into two parts

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis Figure 3.15 Centrioles Plasma membrane Interphase Early prophase Late prophase Nucleolus Nuclear envelope Spindle pole Chromatin Centrioles Forming mitotic spindle Centromere Chromosome, consisting of two sister chromatids Fragments of nuclear envelope Centromere Spindle microtubules MetaphaseAnaphase Telophase and cytokinesis Daughter chromosomes Sister chromatids Nuclear envelope forming Nucleolus forming Spindle Metaphase plate Cleavage furrow

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Stages of Mitosis Figure 3.15, step 4 Metaphase Sister chromatids Spindle Metaphase plate