Essentials of Anatomy and Physiology Fifth edition Seeley, Stephens and Tate Slide 2.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 3: Cell Structures and their Functions

Selective Permeability Slide 3.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Membrane permeability is ‘selective’  Some materials pass while others are excluded  Permeability includes movement into the cell and out of the cell

Cellular Physiology: Membrane Transport Slide 3.20 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Membrane Transport – movement of substance into and out of the cell  Transport is by two basic methods  Passive transport  No energy (ATP) is required  Active transport  The cell must provide ATP

Solutions and Transport Slide 3.21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Solution – homogeneous mixture of two or more components  Solvent – dissolving medium (fluid, usually water)  Solutes – components in smaller quantities within a solution (“dissolved particles”)

Solutions and Transport Slide 3.21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  In living systems:  Intracellular fluid – nucleoplasm and cytosol ( cytoplasm )  Interstitial fluid – fluid on the exterior of the cell  interstitial = “in spaces” or…  extracellular = “outside cells”

Passive Transport Processes Slide 3.23 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Diffusion  Particles tend to distribute themselves evenly within a solution  Movement is from high concentration to low concentration, or down a concentration gradient Figure 3.8

Passive Transport Processes Slide 3.24a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Types of diffusion  Simple diffusion  Unassisted process  Solutes are lipid-soluble materials or small enough to pass through membrane pores

Passive Transport Processes Slide 3.24b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Types of diffusion, con’t.  Osmosis – simple diffusion of water  Highly polar water easily crosses  Movement of water depends on solute concentrations  “more concentrated” solutions attract water (“salt draws water”)

Passive Transport Processes Slide 3.24b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Types of diffusion, con’t.  Facilitated diffusion  Substances require a protein carrier for passive transport  Example: glucose movement into cells

Diffusion through the Plasma Membrane Slide 3.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.9

Passive Transport Processes Slide 3.26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Filtration  Water and solutes are forced through a membrane by hydrostatic pressure  A pressure gradient must exist  Solute-containing fluid moves from a high pressure area to a lower pressure area

Active Transport Processes Slide 3.27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Moves substances that are unable to pass by diffusion because…  They may be too large  They may not be able to dissolve in the fat core of the membrane  They may have to move against a concentration gradient

Active Transport Processes Slide 3.28a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Two types of active transport:  Solute pumping  Amino acids, some sugars and ions are transported  ATP moves substances against concentration gradients

Active Transport Processes Slide 3.28b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.10

Active Transport Processes Slide 3.29a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Bulk transport  Exocytosis  Moves materials out of the cell  Material is carried in a membranous vesicle  Vesicle migrates to plasma membrane  Vesicle fuses with plasma membrane  Material is emptied to the outside

Active Transport Processes Slide 3.29b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.11

Active Transport Processes Slide 3.30a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Bulk transport  Endocytosis  Extracellular substances are engulfed by being enclosed in a membranous vesicle  Material is moved into the cell for “processing”

Active Transport Processes Slide 3.30a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Types of endocytosis  Phagocytosis – cell eating  Pinocytosis – cell drinking

Active Transport Processes Slide 3.30b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.12 Phagocytosis Pinocytosis

Cell Life Cycle Slide 3.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cycle has two major periods  Interphase  Cell grows  Cell carries on metabolic processes  DNA replicates

Cell Life Cycle Slide 3.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cell Division  Cell replicates itself  Function is to produce more cells for growth and repair processes

Cell Life Cycle Slide 3.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Interphase  Longest phase  Averages 96% of cell life cycle  Cell “does” what it is specialized to do  Toward end, DNA replicates  Cell prepares for division

DNA Replication Slide 3.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Genetic material duplicates  Occurs toward end of interphase  DNA uncoils, each strand serves as a template for a new strand  Requires enzymes and ATP Figure 3.13

DNA Replication Slide 3.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Utilizes stored nucleotides  From nucleolus  Enzymes are used to add complementary DNA nucleotides  A=T  C=G Figure 3.13

DNA Replication Slide 3.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Produces two identical strands of DNA  Half of each is from the “parent” strand  Half of each is “new” DNA  Called “semiconservative” replication Figure 3.13

Events of Cell Division Slide 3.33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Mitosis  Division of the nuclear material  Results in the formation of two daughter nuclei  Identical to parent nucleus  Identical to each other

Events of Cell Division Slide 3.33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cytokinesis  Division of the cytoplasm  Begins when mitosis is near completion  Results in the formation of two daughter cells

Stages of Mitosis Slide 3.34a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Interphase  No cell division occurs  The cell carries out normal metabolic activity and growth  Long, complex phase  Toward end, DNA replicates

Stages of Mitosis: Interphase Slide 3.36a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.14; 1

Stages of Mitosis Slide 3.34a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Prophase  First part of cell division  Centrioles migrate to the poles  Nuclear membrane, nucleolus “disappear”  Chromosomes become visible

Stages of Mitosis: Prophase Slide 3.36a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.14; 1

Stages of Mitosis Slide 3.34b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Metaphase  Spindles attach to chromosomes  Chromosomes align around “equator” of the cell

Stages of Mitosis: Metaphase Slide 3.36b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.14; 2 Sister Chromatids

Stages of Mitosis Slide 3.35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Anaphase  Daughter chromosomes are pulled toward the poles  By spindle fibers  The cell begins to elongate

Stages of Mitosis: Anaphase Slide 3.36b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.14; 2

Stages of Mitosis Slide 3.35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Telophase  Daughter nuclei begin forming  A cleavage furrow (for cell division) begins to form

Stages of Mitosis: Telophase Slide 3.36b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.14; 2

Cell Life Cycle Slide 3.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cytokinesis  Division of the cytoplasm and organelles  Functions to distribute material to new daughter cells  Each receives ~1/2 the “stuff”  Cell can now begin to grow and function