Download to read offline
More Related Content
![Chapt03 Holes Lecture Animation[1]](https://cdn.slidesharecdn.com/ss_thumbnails/chapt03holeslectureanimation1-091122121657-phpapp02-thumbnail.jpg?width=640&height=640&fit=bounds)
Ch. 3 Cells.ppt
- 1. Copyright © TheMcGraw-Hill Companies, Inc. Permission required for reproduction or display. Cells
- 2. 2 3.1: Introduction • Thebasic organizational structure of the human body is the cell. • There are 50-100 trillion cells in the human body. • Differentiation is when cells specialize. • As a result of differentiation, cells vary in size and shape due to their unique function.
- 3. 3 3.2: A CompositeCell • Microtubules Flagellum Nuclear envelope Basal body Chromatin Ribosomes Cell membrane Mitochondrion Cilia Microtubules Microtubule Centrioles Microvilli Lysosomes Nucleolus Nucleus Phospholipid bilayer Smooth Endoplasmic reticulum Rough Endoplasmic reticulum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Golgi apparatus Secretory vesicles
- 4. • Major partsinclude: • Nucleus • contains DNA • Cytoplasm • cellular contents between plasma membrane & nucleus • Cell membrane • selective barrier 4
- 5. Cell Membrane (aka PlasmaMembrane) • Outer limit of the cell • Controls what moves in and out of the cell • Selectively permeable • Phospholipid bilayer • Water-soluble “heads” form surfaces (hydrophilic) • Water-insoluble “tails” form interior (hydrophobic) • Permeable to lipid-soluble substances • Cholesterol stabilizes the membrane 5
- 6. 6 Cell Membrane Cell membrane Cellmembrane (b) (a) “Heads” of phospholipid “Tails” of phospholipid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Biophoto Associates/Photo Researchers, Inc. Fibrous protein Carbohydrate Glycolipid Glycoprotein Extracellular side of membrane Cytoplasmic side of membrane Cholesterol molecules Globular protein Double layer of Phospholipid molecules Hydrophobic fatty acid “tail” Hydrophilic Phosphate “head” Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 7. 7 Cytoplasm • Cytosol =water • Organelles = solids Cytoplasm is really like a Jello fruit salad where the Jello is the cytosol and the fruits (oranges, grapes, bananas, maybe walnuts, etc.) are the organelles.
- 8. 8 Organelles Endoplasmic Reticulum (ER) •Connected, membrane-bound sacs, canals, and vesicles • Transport system • Rough ER • Studded with ribosomes • Smooth ER • Lipid synthesis • Added to proteins arriving from rough ER • Break down of drugs Ribosomes • Free floating or connected to ER • Provide structural support and enzyme activity to amino acids to form protein (protein synthesis) Membranes Ribosomes Membranes (b) (c) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 9. 9 Organelles Golgi apparatus • Stackof flattened, membranous sacs • Modifies, packages and delivers proteins Vesicles • Membranous sacs • Store substances Inner membrane Outer membrane Cristae (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Bill Longcore/Photo Researchers, Inc. Mitochondria • Membranous sacs with inner partitions • Generate energy
- 10. 10 Organelles Lysosomes • Enzyme-containing sacs • Digestworn out cell parts or unwanted substances Peroxisomes • Enzyme-containing sacs • Break down organic molecules •Detoxifies alcohol Centrosome • Two rod-like centrioles • Used to produce cilia and flagella • Distributes chromosomes during cell division (a) (b) Centriole (cross-section) Centriole (longitudinal section) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Don W. Fawcett/Visuals Unlimited
- 11. 11 Organelles Cilia • Short hair-likeprojections • Propel substances on cell surface Flagellum • Long tail-like projection • Provides motility to sperm (a) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Oliver Meckes/Photo Researchers, Inc. © Colin Anderson/Brand X/CORBIS
- 12. 12 Microfilaments and microtubules •Thin rods and tubules • Support cytoplasm • Allows for movement of organelles Organelles Microtubules Microfilaments Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © M. Schliwa/Visuals Unlimited
- 13. 13 Cell Nucleus • Isthe control center of the cell • Nuclear envelope • Porous double membrane • Separates nucleoplasm from cytoplasm • Nucleolus • Dense collection of RNA and proteins • Site of ribosome production • Chromatin • Fibers of DNA and proteins • Stores information for synthesis of proteins Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nucleus Nucleolus Chromatin (a) Nuclear pores Nuclear envelope
- 14. 3.3: Movements Into andOut of the Cell There are 2 ways substances move through the cell membrane. 14 •Passive mechanisms do not require energy. • Simple diffusion • Facilitated diffusion • Osmosis • Filtration Active mechanisms require cell energy • Active transport • Endocytosis • Exocytosis • Transcytosis
- 15. 15 Simple Diffusion •The processby which molecules or ions scatter or spread spontaneously from a higher concentration to a lower concentration • Oxygen and carbon dioxide can diffuse readily through the cell membrane •Equilibrium is reached. Time Solute molecule Water molecule A B A B (2) (3) Permeable membrane A B (1)
- 16.
- 17. 17 Facilitated Diffusion • Substancesthat are not able to pass through the lipid bilayer need the help of membrane proteins to get across, this is called Facilitated Diffusion •Carrier molecules “revolving doors” are used to carry large molecules (transported substance) across the membrane. • Ex. Glucose and amino acids Region of higher concentration Transported substance Region of lower concentration Protein carrier molecule Cell membrane
- 18. 18 Animation: How Facilitated Diffusion Works Pleasenote that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.
- 19. 19 Osmosis • The diffusionof water • Water moves toward a higher concentration of solutes Time Protein molecule Water molecule A B A B (1) (2) Selectively permeable membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 20. 20 Animation: How Osmosis Works Pleasenote that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.
- 21. 21 Osmosis and Osmotic Pressure •Osmotic Pressure – ability of osmosis to generate enough pressure to move a volume of water • Osmotic pressure increases as the concentration of nonpermeable solutes increases • Isotonic – same osmotic pressure • Hypertonic – higher osmotic pressure (water loss) • Hypotonic – lower osmotic pressure (water gain) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © David M. Phillips/Visuals Unlimited (b) (a) (c)
- 22. 22 Filtration • Smaller moleculesare forced through porous membranes • Hydrostatic pressure important in the body • Molecules leaving blood capillaries Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary wall Larger molecules Smaller molecules Blood pressure Blood flow Tissue fluid
- 23. 23 Active Transport • Theprocess that moves particles through membranes from regions of lower concentration to regions of higher concentration • Equilibrium is never reached. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Carrier protein Binding site (a) (b) Cell membrane Carrier protein with altered shape Phospholipid molecules Transported particle Cellular energy Region of higher concentration Region of lower concentration
- 24. 24 Active Transport: Sodium-Potassium Pump •Active transport mechanism • Creates balance by “pumping” three (3) sodium (Na+) OUT and two (2) potassium (K+) INTO the cell • 3:2 ratio
- 25. 25 QuickTime™ and a decompressor areneeded to see this picture.
- 26. 26 Endocytosis • Cell engulfsa substance by forming a vesicle around the substance • Three types: • Pinocytosis – substance is mostly water • Phagocytosis – substance is a solid • Receptor-mediated endocytosis – requires the substance to bind to a membrane-bound receptor Nucleus Nucleolus Particle Vesicle Phagocytized particle Cell membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 27. 27 Endocytosis Cytoplasm Vesicle (a) (b) (c)(d) Receptor protein Cell membrane Molecules outside cell Cell membrane indenting Receptor-ligand combination Nucleus Nucleolus Particle Vesicle Phagocytized particle Cell membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 28. 28 Exocytosis • Reverse ofendocytosis • Substances in a vesicle fuse with cell membrane • Contents released outside the cell • Release of neurotransmitters from nerve cells Nucleus Endoplasmic reticulum Golgi apparatus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 29. 29 Transcytosis • Endocytosis followedby exocytosis • Transports a substance rapidly through a cell • HIV crossing a cell layer Viruses bud HIV Exocytosis Receptor-mediated endocytosis HIV-infected white blood cells Anal or vaginal canal Lining of anus or vagina (epithelial cells) Virus infects white blood cells on other side of lining Receptor-mediated endocytosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell membrane
- 30. 30 3.4: The CellCycle • Series of changes a cell undergoes from the time it forms until the time it divide • Stages: • Interphase • Mitosis • Cytokinesis Apoptosis G2 phase Cytokinesis Restriction checkpoint Remain specialized Proceed to division S phase: genetic material replicates G1 phase cell growth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 31. Interphase 31 Apoptosis G2 phase Cytokinesis Restriction checkpoint Remain specialized Proceed to division Sphase: genetic material replicates G1 phase cell growth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Very active period • 3 Phases are involved • During the G1 phase, the cell grows • During the S phase, the cell replicates DNA • During the G2 phase, the cell is in preparation for cell division
- 32. Mitosis • Produces twodaughter cells from an original somatic cell • Nucleus divides – karyokinesis • Cytoplasm divides – cytokinesis • Phases of nuclear division: • Prophase – chromosomes form; nuclear envelope disappears • Metaphase – chromosomes align midway between centrioles • Anaphase – chromosomes separate and move to centrioles • Telophase – chromatin forms; nuclear envelope forms 32
- 33. 33 Mitosis Telophase and Cytokinesis Nuclearenvelopes begin to reassemble around two daughter nuclei. Chromosomes decondense. Spindle disappears. Division of the cytoplasm into two cells. Anaphase Sister chromatids separate to opposite poles of cell. Events begin which lead to cytokinesis. Metaphase Chromosomes align along equator, or metaphase plate of cell. Prophase Chromosomes condense and become visible. Nuclear envelope and nucleolus disperse. Spindle apparatus forms. Late Interphase Cell has passed the restriction checkpoint and completed DNA replication, as well as replication of centrioles and mitochondria, and synthesis of extra membrane. Early Interphase of daughter cells— a time of normal cell growth and function. Cleavage furrow Nuclear envelopes Nuclear envelope Chromatin fibers Chromosomes Spindle fiber Centromere Aster Centrioles Late prophase Sister chromatids Microtubules Mitosis Cytokinesis S phase G1 phase Interphase Restriction checkpoint (a) (b) (c) (d) (e) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ed Reschke G2 phase
- 34. 34 Animation: Mitosis and Cytokinesis Pleasenote that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.
- 35. 35 Cytoplasmic Division • Alsoknown as cytokinesis • Begins during anaphase • Continues through telophase • Contractile ring pinches cytoplasm in half
- 36. 36 Animation: Control of theCell Cycle Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.
- 37. 37 3.5: Control ofCell Division • Cell division capacities vary greatly among cell types • Skin and blood cells divide often and continually • Neuron cells divide a specific number of times then cease • Chromosome tips (telomeres) that shorten with each mitosis provide a mitotic clock • Cells divide to provide a more favorable surface area to volume relationship • Growth factors and hormones stimulate cell division • Hormones stimulate mitosis of smooth muscle cells in uterus • Epidermal growth factor stimulates growth of new skin • Tumors are the consequence of a loss of cell cycle control • Contact (density dependent) inhibition
- 38. 38 Tumors • Two typesof tumors: • Benign – usually remains localized • Malignant – invasive and can metastasize; cancerous • Two major types of genes cause cancer: • Oncogenes – activate other genes that increase cell division • Tumor suppressor genes – normally regulate mitosis; if inactivated they are unable to regulate mitosis • Cells are now known as “immortal” Normal cells (with hairlike cilia) Cancer cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Tony Brain/Photo Researchers, Inc.;
- 39. 39 Animation: How Tumor SuppressorGenes Block Cell Division Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer.
- 40. 40 3.6: Stem andProgenitor Cells • Stem cell: • Can divide to form two new stem cells • Self-renewal • Can divide to form a stem cell and a progenitor cell • Totipotent – can give rise to every cell type • Pluripotent – can give rise to a restricted number of cell types • Progenitor cell: • Committed cell • Can divide to become any of a restricted number of cells • Pluripotent
- 41. 41 Stem and ProgenitorCells one or more steps Sperm Egg Fertilized egg Stem cell Stem cell Progenitor cell Progenitor cell Progenitor cell Blood cells and platelets Fibroblasts (a connective tissue cells) Bone cells Progenitor cell Astrocyte Neuron Skin cell Sebaceous gland cell produces another stem cell (self-renewal) Progenitor cell Progenitor cell Progenitor cell Progenitor cell Progenitor cell Progenitor cell Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
- 42. 42 3.7: Cell Death Apoptosis: •Programmed cell death • Acts as a protective mechanism • Is a continuous process