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Cell Structure and Function

Cell Structure and Function

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Cell Structure and Function

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  1. Cell Structure and Function A & P

  2. Anatomy A-Day 10/26/18 Bellringer • This is often called the pacemaker of the heart • When blood enters the right ventricle, where does it travel to next? Agenda • Bellringer • Go over lab practical • Cell Introduction • Cell Notes • Organelle Mania Sign-up

  3. Anatomy A-Day 10/26/18 Bellringer • This is often called the pacemaker of the heart • SA Node • When blood enters the right ventricle, where does it travel to next? • Pulmonary arteries Agenda • Bellringer • Go over lab practical • Cell Introduction • Cell Notes • Organelle Mania Sign-up

  4. Anatomy A-Day 10/30/18 Bellringer • Which type of cell contains a nucleus? • What are the differences between plant and animal cells? Agenda • Bellringer • Cell Membrane Notes • Organelle Mania

  5. Anatomy A-Day 10/30/18 Bellringer • Which type of cell contains a nucleus? Eukaryote • What are the differences between plant and animal cells? Cell wall, large vacuole and chloroplast Agenda • Bellringer • Cell Membrane Notes • Organelle Mania

  6. Anatomy A-Day 11/1/18 Bellringer • What is the role of the mitochondria? • What is the role of the ribosome? Agenda • Bellringer • Finish Cell Notes • Cancer Research in Computer Lab

  7. Anatomy A-Day 11/1/18 Bellringer • What is the role of the mitochondria? Make energy for the cell (powerhouse) • What is the role of the ribosome? Make proteins Agenda • Bellringer • Finish Cell Notes • Cancer Research in Computer Lab

  8. Why Study Cell Biology? The key to every biological problem must finally be sought in the cell, for every living organism is, or at some time has been, a cell. E.B. Wilson, 1925

  9. Cells are Us

  10. Cells are Us Cilia on a protozoan Sperm meets egg

  11. Red and white blood cells above vessel-forming cells. nerve cell Cells are Us A person contains about 100 trillion cells. That’s 100,000,000,000,000 or 1 x 1014 cells. There are about 200 different cell types in mammals (one of us). Cells are tiny, measuring on average about 0.002 cm (20 um) across. That’s about 1250 cells, “shoulder-to-shoulder” per inch.

  12. Discovery of the Cell • Englishman Robert Hooke in 1665 used an early compound microscope to look at cork • What is cork? • Plant material – therefore has plant cells • Called them “cells” because they reminded him of a monastery’s rooms, called cells • Anton van Leeuwenhoek in 1674 observed pond life in a microscope

  13. Schleiden Schwann The Cell Theory The cell theory (proposed independently in 1838 and 1839) is a cornerstone of biology. All organisms are composed of one or more cells. Cells are the smallest living things. Cells arise only by division of previously existing cells. All organisms living today are descendents of an ancestral cell.

  14. A prokaryotic cell A eukaryotic cell Two Fundamentally Different Types of Cells

  15. Us vs. Them -Eukaryotes and Prokaryotes

  16. Eukaryotic Cells • Eukaryotic cell can be likened to a factory • There are many structure in eukaryotic cells. • These are called organelles – “little organs” • Two major parts of cell: • Nucleus • Cytoplasm – portion of cell outside nucleus

  17. An Idealized Animal Cell

  18. Major Divisions of the Eukaryotic Cell

  19. A rat liver cell (with color enhancement to show organelles)

  20. It’s Crowded In There An artist’s conception of the cytoplasm - the region of a cell that’s not in the nucleus or within an organelle.

  21. Animal and Plant Cells Have More Similarities Than Differences

  22. Cellular Anatomy We’ll start by seeing what role these parts play in making and moving proteins.

  23. The Nucleus • The nucleus (plural: nuclei) is a large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA. • The nucleus controls many of the cell’s activities. • Eukaryotes are cells that contain nuclei. • Prokaryotes are cells that do not contain nuclei.

  24. The Nucleus Think of the nucleus as the cell’s control center. • Contains nearly all of cell’s DNA – the instructions for making proteins • Surrounded by nuclear envelope • Most cells have one nucleus • RBCs have 0 • Skeletal muscle cells have many Two meters of human DNA fits into a nucleus that’s 0.000005 meters across.

  25. The Nucleus • Granular material is called chromatin – DNA bound to protein • When cell divides, chromatin condenses to form chromosomeswhich pass genetic information on to new cells • Nucleolus - Dense region of nucleus where ribosomes are assembled

  26. Ribosomes and the Endoplasmic Reticulum

  27. Ribosomes • Ribosomes – sites of protein assemblage • Follow instructions from nucleus

  28. The Rough Endoplasmic Reticulum Functions: Protein synthesis (about half the cell’s proteins are made here). Protein movement (trafficking) Protein “proofreading”

  29. Golgi Apparatus • Proteins produced in ER then move into Golgi Apparatus. • Function – modify, sort, package proteins • Proteins then transported to elsewhere in the cell or outside the cell

  30. The Lysosome Functions: Digesting food or cellular invaders Recycling cellular components Cell suicide – programmed cell death (The lysosome is not found in plant cells)

  31. The Mitochondrion Think of the mitochondrion as the powerhouse of the cell. Both plant and animal cells contain many mitochondria. (Mitochondria is the plural of mitochondrion)

  32. Mitochondria • Mitochondria – convert chemical energy stored in food into compounds the cell can use • Inner and outer membrane • Inherited from mother • Cells that need more energy will have more mitochondria (white meat vs. dark meat)

  33. An animal cell cytoskeleton The Cytoskeleton The name is misleading. The cytoskeleton is the skeleton of the cell, but it’s also like the muscular system, able to change the shape of cells in a flash.

  34. A Cytoskeleton Gallery

  35. The Cytoskeleton in Action A white blood cell using the cytoskeleton to “reach out” for a helpless bacterium.

  36. Cell Membrane • Forms outer boundary of cell • Separates contents from environment • Made mainly of lipids and proteins • Regulates movement into and out of the cell

  37. Membrane Structure • Lipids consist of phosphate heads that are hydrophilic • Tails consist of fatty acids that are hydrophobic • Two layers in all • Proteins imbedded in and on membrane • Together they are called the “Fluid Mosaic Model”

  38. Membrane Proteins • Channel proteins – go through membrane and allow for passage into and out of cell • Receptor proteins – receive information from other cells (hormones) • I.D. proteins – identify whose cells and what type of cells • Carrier protein – transmit material that is too large into and out of cell (facilitated diffusion)

  39. Membrane Movements • Equilibrium – when the concentration of a solute is the same throughout the system • Diffusion – movement of solute from high to low concentration • Heat, size, concentration, solubility all affect rate • Osmosis – water diffusion through a selectively permeable membrane

  40. Cellular Movements • Facilitated Diffusion – still diffusion (w/o energy input) but must have a carrier protein to get through • Think of needing to have a ticket to go to a concert

  41. Cellular Movements • Active Transport – carrier-mediated facilitated diffusion that requires ATP • Goes against the conc. Gradient or from lo – hi • Because particles are going the “wrong way” energy is required in the form of ATP

  42. Sodium – Potassium Pump • Simultaneously carries Na+ ions out of and K+ ions into the cell • ATP provides energy to move 3 sodium ions out and 2 potassium ions in against gradients • Allows for normal transmission of impulses by nerve cells

  43. Membrane Movements • Endocytosis – engulf particle into cell; nutrient acquistion • Phagocytosis – “cell eating”; endocytosis of large particles such as bacteria; protective mechanism • Pinocytosis – “cell drinking” gulping droplets of extracellular fluid; routine absorption • Exocytosis – cell products and waste released from cell

  44. Variations of Cells Largest Cell Longest Cell

  45. Cell Size Limitations • Diffusion limits cell size • Slow and inefficient over large areas • DNA limits cell size • Limit to how quickly DNA can be read • Limit to # of proteins built/period of time • Surface area to volume ratio limits cell size • Volume increases faster than surface area • Requires more nutrients, produces more waste, but with relatively smaller surface area

  46. Question • Which one of these has the best ratio of surface area to cell volume?

  47. Cell Reproduction • All cells in the world today came from preexisting cells (Cell Theory) • How does this happen? • The cell cycle

  48. Cell Life Cycle • The cell life cycle is the series of changes a cell goes through from the time it forms until it divides. • Two major periods: • Interphase– cell grows and carries on metabolic activities • Cell Division – cell reproduces itself

  49. The Cell Cycle • Interphase • G1: Growth… • S: Copy the DNA... • G2: Growth… • Mitosis • Process which forms two daughter cells.

  50. Interphase • Longest phase in cell cycle (90+% of time) • Cell is very active Plant Cell Animal Cell