1. Cell Structure and Function What color are cells in the body? clear

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

4. Cell Characteristics Plasma (cell) Membrane –Outer cell boundary Cytoplasm –Composed of cytoplasmic organelles ER, ribosomes, centrioles, mitochondria, Golgi complex, lysosomes and vacuoles Organelles –Specialized structures that perform specific functions

5. Plasma Membrane Intracellular versus extracellular Selectively permeable Fluid-mosaic model: regulate the passage of nutrients and waste Composed of proteins and lipids

6. Nucleus DNA dispersed throughout; controls and integrates the function of the entire cell 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 where rRNA is manufactured

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

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

9. Ribosomes Sites of protein synthesis Composed of a large and small subunit Types –Free –Attached to endoplasmic reticulum Found in both eukaryotes and prokaryotes

10. Endoplasmic Reticulum Extension of outer nuclear membrane Types –Rough Attached ribosomes Proteins produced and modified for secretion and for internal use –Smooth No attached ribosomes Manufacture lipids Cisternae: Interior spaces isolated from rest of cytoplasm Transports nutrients to the nucleus and provides some cell structure

11. Golgi Apparatus Modification, packaging, distribution of proteins and lipids for secretion or internal use produced by ER Flattened membrane sacs stacked on each other

12. Function of Golgi Apparatus

13. Mitochondria Provide energy for cell Major site of ATP synthesis Membranes –Crista: Infoldings of inner membrane –Matrix: Substance located in space formed by inner membrane

14. 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 in eukaryotic cells

15. Cilia Appendages projecting from cell surfaces Capable of movement Moves materials over the cell surface

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

17. 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

18. Prokaryotes Simple cells which lack a membrane bound nucleus Initial or primitive cell type found on earth Less complex than eukaryotes –Have no organelles (microtubules or centrioles) –Examples include bacteria Division is by binary fission

19. Eukaryotes Evolved from prokaryotes; they have a true nucleus Structurally and biochemically more complex –Examples include protozoa, fungi, algae, plant and animal cells Golgi apparatus is the structure in eukaryotic cells which secretes substances

20. Viruses Acellular: neither prokaryotic or eukaryotic Contain nucleic acid and either RNA or DNA but not both Depend on the energy of the host cell Has protective coat which makes them hard to control; antibiotics have no effect Bacteriophage: virus which invades bacteria Examples of viral diseases: measles, chickenpox, mumps, mono, hepatitis, AIDs

21. Overview of Cell Metabolism

22. Movement through the Plasma Membrane Four different modes –Directly through the plasma membrane Small, uncharged, hydrophobic molecules Osmosis –Membrane channels Rapid movement of water, charged small molecules –Carrier molecules Large polar molecules that are not lipid soluble Glucose –Vesicles Large non-lipid soluble molecules, small pieces of matter, whole cells Small sac surrounded by membrane

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

24. Diffusion Movement of solutes from an area of higher concentration to lower concentration in solution Only applies to small, hydrophobic, uncharged molecules Factors that influence rate of diffusion –Temperature of solution –Distance –Size of diffusing molecules –Concentration or density gradient Difference between two points –Viscosity How easily a liquid flows

25. Osmosis Diffusion of water (solvent) across a selectively permeable membrane ( water most abundant compound in cell ) Important because large volume changes caused by water movement disrupt normal cell function Cell shrinkage or swelling –Isotonic: equal concentration on both sides cell neither shrinks nor swells –Hypertonic: Less water/more solute than other side cell shrinks (crenation) –Hypotonic: More water/less solute than other side cell swells (lysis)

26. Osmosis Osmotic pressure – force required to prevent the movement of water a solution by osmosis across a selectively permeable membrane The greater the concentration of the solution (the more hypertonic the solution) the greater the osmotic pressure The greater the osmotic pressure the greater the tendency for water to move into the solution

27. Osmosis

28. 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

29. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Solute Solvent

30. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

32. Diffusion

33. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Semipermeable membrane

34. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Semipermeable membrane

35. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Semipermeable membrane Concentration of solute LowHigh

36. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Semipermeable membrane Concentration of solute LowHigh Water moves towards high solute concentration

37. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Semipermeable membrane Concentration of solute LowHigh Water moves towards high solute concentration

38. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Semipermeable membrane Concentration of solute LowHigh Equal concentrations of solute = Dynamic equilibrium Water moves towards high solute concentration

39. Osmosis

40. Mediated Transport Mechanisms Involve carrier proteins Characteristics –Specificity To a single type of molecule –Competition Result of similar molecules binding to carrier protein Substance that is in greater concentration or binds more readily moves at a greater rate –Saturation Rate of transport limited to number of available carrier proteins

41. Saturation of a Carrier Protein

42. Mediated Transport Mechanisms Facilitated diffusion –Higher to lower concentration without metabolic energy Active transport –Requires ATP –Can move substances from areas of lower concentration to areas of higher concentration Secondary active transport –Ions or molecules can move in same (symport) or different direction (antiport)

43. Secondary Active Transport

44. 04.09 Transport Moves Substances Slide number: 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Area of high concentration Area of low concentration A Simple diffusion B Facilitated diffusion— channel C Facilitated diffusion— carrier Passive transport No energy required Active transport Energy required ATPADP+P D

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

46. Pinocytosis and Receptor-Mediated Endocytosis

47. 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

48. Chromosome Structure

49. Overview of Protein Synthesis

50. Transcription –Copies DNA to form mRNA Translation –Synthesis of a protein at ribosome –tRNA carries amino acids to ribosome

52. Post-transcriptional Processing

53. Overview of Protein Synthesis

54. Translation

55. Post-translational Processing Proproteins = proteins that are longer when they are first made than when they are in their final functional state –Non-functional/extra portions are cleaved off to make functional protein Proenzyme = proproteins that are going to be functional enzymes –Made as non-functional enzymes because they would digest the cell if made in functional form originally –Made functional when they reach a protected area of the body Polyribosome = when multiple ribosomes attach to one mRNA strand in order to make many copies of the same protein

56. Protein Synthesis Regulation During development and cell differentiation part of DNA molecules become inactivated and is not transcribed –Ex: DNA coding for hemoglobin is inactivated and not transcribed except for in developing red blood cells Protein synthesis can be controlled internally or be affected by regulatory substances secreted by other cells Cell life cycle

57. Cell Life Cycle Interphase –Phase between cell divisions Mitosis –Division of the nucleus into two identical nuclei –Prophase –Metaphase –Anaphase –Telophase Cytokinesis –Division of cell cytoplasm

58. Mitosis Occurs in all somatic cells –Have diploid number of chromosomes (2n) 2 of each type of chromosome Humans = 46 chromosomes = 23 pairs of chromosomes –22 of these pairs are autosomes »Non-sex chromosomes –Each autosomal pair is made up of two homologous chromosomes »Same in structure and gene arrangement

59. Genetic Diversity

61. Spermatogenesis

62. Oogenesis

63. Problems in Meiosis

64. Comparison of Mitosis and Meiosis