3-1 Anatomy and Physiology, Sixth Edition Rod R. Seeley Idaho State University Trent D. Stephens Idaho State University Philip Tate Phoenix College Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Chapter 03 Lecture Outline *

3-2 Chapter 3 Cell Structure and Function

3-3 Cell Characteristics Plasma Membrane –Outer cell boundary Cytoplasm –Cytosol –Cytoskeleton –Cytoplasmic inclusions Organelles –Specialized structures that perform specific functions

3-4 Functions of the Cell Basic unit of life Protection and support Movement Communication Cell metabolism and energy release Inheritance

3-5

3-6 Plasma Membrane Intracellular versus extracellular Membrane potential Glycolipids and glycoproteins Fluid-mosaic model

3-7 Membrane Lipids Phospholipids form a lipid bilayer –Hydrophilic (water-loving) polar heads –Hydrophobic (water-fearing) nonpolar heads Cholesterol: Determines fluid nature of membrane

3-8 Membrane Proteins Integral or intrinsic –Extend from one surface to the other Peripheral or extrinsic –Attached to either the inner or outer surfaces of the lipid bilayer

3-9 Marker Molecules Allow cells to identify on another or other molecules Glycoproteins Glycolipids Examples: –Immune system –Recognition of oocyte by sperm cell

3-10 Channel Proteins Nongated ion channels –Always open Ligand gated ion channel –Open in response to small molecules that bind to proteins or glycoproteins Voltage-gated ion channel –Open when there is a change in charge across the plasma membrane

3-11 Receptors Receptor molecules –Exposed receptor site Linked to channel proteins –Acetylcholine Linked to G proteins –Alter activity on inner surface of plasma membrane

3-12 Enzymes and Carrier Proteins

3-13 Movement through the Plasma Membrane Diffusion Osmosis Filtration Mediated transport mechanisms –Facilitated diffusion –Active transport –Secondary active transport

3-14 Diffusion Movement of solutes from an area of higher concentration to lower concentration in solution –Concentration or density gradient Difference between two points –Viscosity How easily a liquid flows

3-15 Diffusion

3-16 Osmosis Diffusion of water (solvent) across a selectively permeable membrane Important because large volume changes caused by water movement disrupt normal cell function Cell shrinkage or swelling –Isotonic: cell neither shrinks nor swells –Hypertonic: cell shrinks (crenation) –Hypotonic: cell swells (lysis)

3-17 Osmosis

3-18 Osmosis

3-19 Filtration Works like a sieve Depends on pressure difference on either side of partition Moves from side of greater pressure to lower –Example: In kidneys in urine formation

3-20 Mediated Transport Mechanisms Involve carrier proteins Characteristics –Specificity To a single type of molecule –Competition –Saturation Rate of transport limited to number of available carrier proteins

3-21 Saturation of a Carrier Protein

3-22 Mediated Transport Mechanisms Facilitated diffusion –Higher to lower concentration without metabolic energy Active transport –Requires ATP Secondary active transport –Ions or molecules move in same (symport) or different direction (antiport)

3-23 Secondary Active Transport

3-24 Endocytosis Internalization of substances by formation of a vesicle Types –Phagocytosis –Pinocytosis –Receptor-mediated endocytosis

3-25 Pinocytosis and Receptor-Mediated Endocytosis

3-26 Exocytosis Accumulated vesicle secretions expelled from cell Examples –Secretion of digestive enzymes by pancreas –Secretion of mucus by salivary glands –Secretion of mild by mammary glands

3-27 Cytoplasm Cellular material outside nucleus but inside plasma membrane Cytosol: Fluid portion Cytoskeleton: Supports the cell –Microtubules –Microfilaments –Intermediate filaments Cytoplasmic inclusions

3-28 Organelles Small specialized structures for particular functions Most have membranes that separates interior of organelles from cytoplasm Related to specific structure and function of the cell

3-29 Centrioles In specialized zone near nucleus: Centrosome Each unit consists of microtubules Before cell division, centrioles divide, move to ends of cell and become spindle fibers

3-30 Cilia Appendages projecting from cell surfaces Capable of movement Moves materials over the cell surface

3-31 Flagella Similar to cilia but longer Usually only one exists per cell Move the cell itself in wavelike fashion Example: Sperm cell

3-32 Microvilli Extension of plasma membrane Increase the cell surface Normally many on each cell One tenth to one twentieth size of cilia Do not move

3-33 Ribosomes Sites of protein synthesis Composed of a large and small subunit Types –Free –Attached to endoplasmic reticulum

3-34 Endoplasmic Reticulum Types –Rough Attached ribosomes Proteins produced and modified –Smooth Not attached ribosomes Manufacture lipids Cisternae: Interior spaces isolated from rest of cytoplasm

3-35 Golgi Apparatus Modification, packaging, distribution of proteins and lipids for secretion or internal use Flattened membrane sacs stacked on each other

3-36 Function of Golgi Apparatus

3-37 Action of Lysosomes

3-38 Peroxisomes and Proteasomes Peroxisomes –Smaller than lysosomes –Contain enzymes to break down fatty and amino acids –Hydrogen peroxide is a by-product of breakdown Proteasomes –Consist of large protein complexes –Include several enzymes that break down and recycle proteins in cell

3-39 Mitochondria Provide energy for cell Major site of ATP synthesis Membranes –Cristae: Infoldings of inner membrane –Matrix: Substance located in space formed by inner membrane

3-40 Nucleus DNA dispersed throughout Consists of : –Nuclear envelope: Separates nucleus from cytoplasm and regulates movement of materials in and out –Chromatin: Condenses to form chromosomes during cell division –Nucleolus: Assembly site of large and small ribosomal units

3-41 Chromosome Structure

3-42 Overview of Cell Metabolism

3-43 Overview of Protein Synthesis

3-44 Overview of Protein Synthesis Transcription –Copies DNA to form mRNA –tRNA carries amino acids to ribosome Translation –Synthesis of a protein at ribosome

3-45 Translation

3-46 Cell Life Cycle Interphase –Phase between cell divisions Mitosis –Prophase –Metaphase –Anaphase –Telophase Cytokinesis –Division of cell cytoplasm

3-47 Mitosis

3-48 Mitosis

3-49 Meiosis

3-50 Comparison of Mitosis and Meiosis

3-51 Cellular Aspects of Aging Cellular clock Death genes DNA damage Free radicals Mitochondrial damage