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Human Genetics

Human Genetics. Concepts and Applications Eighth Edition. Powerpoint Lecture Outline. Ricki Lewis Prepared by Dubear Kroening University of Wisconsin-Fox Valley. Chapter 2 Cells. Cells The Basic Unit of Life. Organisms can be single cells or collections of many cells

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Human Genetics

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  1. Human Genetics Concepts and Applications Eighth Edition Powerpoint Lecture Outline Ricki Lewis Prepared by Dubear Kroening University of Wisconsin-Fox Valley

  2. Chapter 2Cells

  3. Cells The Basic Unit of Life • Organisms can be single cells or collections of many cells • Mutations affect whether the cell functions normally • Cell numbers are important, critical to growth, development, and healing

  4. Human Cells • > 260 cell types • Four categories • Epithelial • Muscle • Nerve • Connective

  5. Types of Cells • Prokaryotic cells Lack a nucleus • Eukaryotic cells Contain a nucleus and complex organelles Figure 2.2

  6. Domains of Life Genetic material Domain in a compartment? Example Archaea no (prokaryote) Methanopyrus Bacteria no (prokaryote) E. coli Eukarya yes (eukaryote) amoeba, plant, human

  7. Macromolecules in Cells Carbohydrates sugars, starches energy Lipids fats, oils membranes Proteins myosin, collagen structures, enzymes Nucleic acids DNA, RNA genetic material

  8. An Animal Cell • Surrounded by the plasma membrane • Contains a nucleus and cytoplasm with specialized organelles Figure 2.3

  9. Structures and Functions of Organelles Table 2.1

  10. The Nucleus • Surrounded by double layered nuclear membrane • Contains • Nuclear pores thatallow movement of some molecules in and out • Nucleolus, which is the site of RNA production • Chromosomes composed of DNA and proteins

  11. Figure 2.4 Figure 2.3

  12. Secretion Figure 2.5

  13. Endoplasmic Reticulum (ER) • Interconnected membranous tubules and sacs • Rough ER contains ribosomes, site of protein synthesis • Smooth ER does not contain ribosomes and is important in lipid synthesis Figure 2.3

  14. Golgi Apparatus • Final protein folding • Stores secreted material • Forms sugars, glycoproteins, and glycolipids • Vesicles of material are released Figure 2.3

  15. Lysosomes • Break down bacteria, cellular debris, and nutrients • Contain > 40 types of digestive enzymes • Tay-Sachs is an inherited lysosomal storage disorder Figure 2.6

  16. Peroxisomes • Contain several types of enzymes • Break down lipids, rare biochemicals • Synthesize bile acids • Detoxify compounds from free radicals • Abundant in liver and kidney cells

  17. Mitochondria • Site of ATP (energy) production • Has its own circular DNA • Mitochondrial genes are inherited from the mother Figure 2.7

  18. Plasma Membrane • Selectively permeable • A phospholipid bilayer forms a hydrophobic barrier • Contains proteins, glycoproteins, and glycolipids • Important to cell function and interactions • May be receptors • Form channels for ions Figure 2.8

  19. Figure 2.9

  20. Faulty Ion Channels May Cause Inherited Diseases • Sodium channels – ability to detect pain • Potassium channels – Long-QT syndrome • Chloride channels – cystic fibrosis

  21. Cytoskeleton • Fibers, filaments, and their associated proteins • Dynamic • Functions: Maintain cell shape Connect cells to each other Transport organelles and small molecules Provide cell motility (some cell types) Move chromosomes in cell division Compose cilia

  22. Cytoskeleton Figure 2.10

  23. Cell Division and Death • Are required for normal growth and development. • Mitosis produces new cells • Mitosis occurs in somatic cells (all cells but egg and sperm) • Apoptosis is cell death that is part of normal development • Necrosis is cell death in response to injury

  24. Figure 2.12

  25. The Cell CycleThe sequence of events associated with cell division • S phase: DNA synthesis • G phase: gap for growth • M phase: mitosis (nuclear division) • Cell division or cytokinesis follows Figure 2.13

  26. Stages of the Cell Cycle • Interphase • Prepares for cell division • Replicates DNA and subcellular structures • Composed of G1, S, and G2 • Cells may progress to mitosis or enter G0,a quiescent phase • Mitosis division of the nucleus • Cytokinesis division of the cytoplasm

  27. Replication of Chromosomes • Process of duplicating a chromosome • Occurs prior to division, during S of interphase • Produces sister chromatids • Held together at centromere Figure 2.14

  28. Mitosis • Produces two identical daughter cells • Replicated chromosomes align • Sister chromatids separate and move to opposite poles. • Nuclear membranes form around each new nucleus • Division of cytoplasm or cytokinesis occurs.

  29. Overview of Mitosis Continuous process divided into • Prophase • Metaphase • Anaphase • Telophase

  30. Mitosis in a Human Cell Figure 2.15

  31. Prophase • Replicated chromosomes condense • Microtubules organize into a spindle • Nuclear membrane breaks down Figure 2.15

  32. Metaphase • Chromosomes line up on the metaphase plate • Spindle microtubules are attached to centromeres of chromosomes Figure 2.15

  33. Anaphase • Centromeres divide • Chromosomes move to opposite ends of the cell Figure 2.15

  34. Telophase • Chromosomes uncoil • Nuclear membranes form • Spindle disappears Figure 2.15

  35. Cytokinesis Cytoplasmic division occurs after nuclear division is complete. Two cells are formed.

  36. Cell Cycle Control Proteins called “checkpoint proteins” monitor progression through the cell cycle. Figure 2.16

  37. Telomeres • Located at the ends of the chromosomes • Contain hundreds to thousands of six nucleotide repeats • Most cells lose 50-200 repeats after each cell division • After about 50 divisions, shortened telomeres signal the cell to stop dividing • Sperm, eggs, bone marrow, and cancer cells produce telomerase that prevent shortening of telomere

  38. Apoptosis • Orderly destruction, stepwise process • Caspases destroy cellular components, signal phagocytes to clean up • Mitosis and apotosis work together to form functional body • Cancer can result from too much mitosis, too little apotosis

  39. Apoptosis Programmed cell death is part of normal development Figure 2.18

  40. Cell-Cell Interaction: Signal Transduction The process of transmitting a signal from the environment to a cell Figure 2.19

  41. Signal Transduction • Receptor binds to messenger • Interacts with regulator • Causes enzyme to produce second messenger • Activates enzymes • Amplification due to cascade • Defects cause disease

  42. Cell-Cell Interactions: Cell Adhesion Molecules (CAMs) Figure 2.20

  43. Stem Cells and Cell Specialization • Stem cells and progenitor cells renew tissues • Retain the ability to divide and specialize • Described in terms of potential • Totipotent • Pluripotent

  44. Figure 2.22

  45. Medical Treatments Using Stem Cells • Regenerative medicine • Sources of stem cells • Early embryos from fertility clinics • Somatic cell nuclear transfer • Tissue-based (adult) stem cells • Ethical issues associated with use of embryos

  46. Figure 2.24

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