1. 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 *

2. 3-2 Chapter 3 Cell Structure and Function

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

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

5. 3-5

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

7. 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

8. 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

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

10. 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

11. 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

12. 3-12 Enzymes and Carrier Proteins

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

14. 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

15. 3-15 Diffusion

16. 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)

17. 3-17 Osmosis

18. 3-18 Osmosis

19. 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

20. 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

21. 3-21 Saturation of a Carrier Protein

22. 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)

23. 3-23 Secondary Active Transport

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

25. 3-25 Pinocytosis and Receptor-Mediated Endocytosis

26. 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

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

28. 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

29. 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

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

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

32. 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

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

34. 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

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

36. 3-36 Function of Golgi Apparatus

37. 3-37 Action of Lysosomes

38. 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

39. 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

40. 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

41. 3-41 Chromosome Structure

42. 3-42 Overview of Cell Metabolism

43. 3-43 Overview of Protein Synthesis

44. 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

45. 3-45 Translation

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

47. 3-47 Mitosis

48. 3-48 Mitosis

49. 3-49 Meiosis

50. 3-50 Comparison of Mitosis and Meiosis

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