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Marieb’s Human Anatomy and Physiology Ninth Edition

Marieb’s Human Anatomy and Physiology Ninth Edition. Marieb w Hoehn. Chapter 3 Cells: The Living Units Lecture 6. Lecture Overview. Mitochondria Intro to Cellular Respiration The cell nucleus The cell cycle Mitosis & Meiosis Cell Death Stem & Progenitor Cells.

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Marieb’s Human Anatomy and Physiology Ninth Edition

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  1. Marieb’s Human Anatomy and Physiology Ninth Edition Marieb w Hoehn Chapter 3 Cells: The Living Units Lecture 6

  2. Lecture Overview • Mitochondria • Intro to Cellular Respiration • The cell nucleus • The cell cycle • Mitosis & Meiosis • Cell Death • Stem & Progenitor Cells

  3. Cytoplasmic Organelles (cont’d) - Mitochondria • Mitochondria • membranous sacs with inner partitions • contain their own DNA • generate energy Figure From: Marieb & Hoehn, Human Anatomy & Physiology, 9th ed., Pearson

  4. Overview of Cellular Metabolism Metabolism – All the chemical reactions that occur in an organism ETS Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

  5. Overview of Glucose Breakdown NAD+ NAD+ NAD+FAD Figure from: Hole’s Human A&P, 12th edition, 2010

  6. Overview of Cellular Respiration Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Anaerobic Cellular respiration (aerobic) ATP e- *Most ATP from here e- ETS + e- ATP e- • Structural – Functional Relationship - Inner membrane: • Contains Matrix where TCA cycle takes place • Has enzymes and molecules that allow Electron Transport System to be carried out

  7. Anaerobic Glycolysis & Lactic Acid During glycolysis, if O2 is not present in sufficient quantity, lactic acid is generated to keep glycolysis going so it continues to generate ATP (even without mitochondria) Figure from: Hole’s Human A&P, 12th edition, 2010 NOTE what happens with and without O2 being available…

  8. Cell Nucleus • control center of cell • nuclear envelope (membrane) • porous double membrane • separates nucleoplasm from cytoplasm (*eukaryotes only) • nucleolus • dense collection of RNA and proteins • site of ribosome production • chromatin • fibers of DNA and proteins • stores information for synthesis of proteins Figure From: Marieb & Hoehn, Human Anatomy & Physiology, 9th ed., Pearson

  9. The Cell Cycle • series of changes a cell undergoes from the time it forms until the time it divides • stages • interphase • mitosis • cytoplasmic division • differentiation Figure From: Marieb & Hoehn, Human Anatomy & Physiology, 9th ed., Pearson Differentiatedcells may spend all their time in ‘G0’ (neurons, skeletal muscle, red blood cells). Stem cells may never enter G0

  10. Why the Cell Cycle Must Have Controls 1. DNA/Cell replication must not proceed unless a ‘signal to proceed’ is received 2. DNA must be completely and correctly replicate before mitosis takes place otherwise it should not occur. 3. Chromosomes must be correctly positioned during mitosis so they are separated correctly

  11. What are the Controls of the Cell Cycle? • cell division capacities vary greatly among cell types • skin and bone marrow cells divide often • liver cells divide a specific number of times then cease • chromosome tips (telomeres) that shorten with each mitosis provide a mitotic clock (cell senescence) • 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 • contact inhibition • Cyclins and Cyclin-dependent kinases provide central control • tumors are the consequence of a loss of cell cycle control

  12. The Cell Cycle and Mitosis • INNKEEPER (INTERPHASE) • POUR (PROPHASE) • ME (METAPHASE) • ANOTHER (ANAPHASE) • TEQUILA (TELOPHASE/CYTOKINESIS)

  13. Interphase and Mitosis (IPMAT) Interphase Early Prophase Late Prophase Metaphase Anaphase Telophase/Cytokinesis

  14. Mitosis and Meiosis Figures from: Martini, Anatomy & Physiology, Prentice Hall, 2001 Mitosis – production of two identical diploid daughter cells Meiosis – production of four genetically varied, haploid gametes

  15. Chromosome Crossing Over • mixes up traits • different colors represent the fact that one homologous chromosome comes from the individual’s father (paternal) and one from the mother (maternal) Tetrad Figure from: Hole’s Human A&P, 12th edition, 2010 • the genetic information in sperm cells and egg cells varies from cell to cell

  16. Cell Death • Two mechanisms of cell death • Necrosis • Programmed cell death (PCD or apoptosis) • Necrosis • Tissue degeneration following cellular injury or destruction • Cellular contents released into the environment causing an inflammatory response • Programmed Cell Death (Apoptosis) • Orderly, contained cell disintegration • Cellular contents are contained and cell is immediately phagocytosed

  17. Necrosis vs. Apoptosis Necrosis Apoptosis Figure from: Alberts et al., Essential Cell Biology, Garland Press, 1998

  18. Stem and Progenitor Cells • Stem cell • can divide to form two new stem cells • can divide to form a stem cell and a progenitor cell • totipotent – can give rise to any cell type (Embryonic stem cells) • pluripotent – can give rise to a restricted number of cell types • Progenitor cell • committed cell further along differentiation pathway • can divide to become any of a restricted number of cells • pluripotent • *not self-renewing, like stem cells

  19. Figure from: Hole’s Human A&P, 12th edition, 2010

  20. Summary Table of Cell Respiration

  21. Review • Cellular respiration • The metabolic processes by which ATP is produced • Major cellular steps: • Glycolysis • Cytoplasm • Anaerobic • TCA (Krebs, Citric Acid) cycle • Mitochondria • Aerobic • Electron Transport Chain • Mitochondria • Aerobic • Most ATP produced here

  22. Review • The goal of metabolism • provide the cell with energy (via catabolism; breakdown) and • materials for the manufacture of cellular components (via anabolism; synthesis, building up) • Cell Nucleus • Nuclear envelope (membrane) • porous double membrane • separates nucleoplasm from cytoplasm (*eukaryotes only) • Nucleoli – RNA organizing centers • Chromatin – combination of DNA and RNA

  23. Review • The Cell Cycle • series of changes a cell undergoes from the time it forms until the time it divides • stages can include • interphase (G1, S, G2) • mitosis (PMAT) • cytoplasmic division (cytokinesis) • differentiation (G0; exit from cell cycle)

  24. Review • Cell Death occurs by two processes • Necrosis • Sudden insult to cell causing rapid death • Causes inflammation in surrounding tissues • Programmed Cell Death (apoptosis) • Planned, orderly shutdown of cell • Ubiquitous in normal cellular processes • Does not cause inflammation of surrounding tissues

  25. Review • Mitosis • Identical daughter cells • Diploid number of chomosomes • Meiosis • Used by sex cells • Genetically varied daughter cells • Haploid number of chomosomes • Stem cells – can produce many, if not all, other cell types • Progenitor cells – can produce only a limited number of cell types

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