Biology - Cell Organization & Function


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Biology - Cell Organization & Function

  1. 1. Chapter 3 Cell Structure & FunctionPicture by Molecular Expressions Picture by Cell II: Cellular Organization
  2. 2. 3.1: Microscopes & Cells Objectives  1. Define the cell theory  2. Identify the magnification powers of different types of microscopes  3. Observe how the compound microscope changes an image
  3. 3. Early Microscopes Anton von Leeuwenhoek  (1600s / Dutch) Picture by  Used glass lenses to create instrument that magnified images of very small objects  Light rays bend to make larger image  Earliest light microscope Picture by Mr. Cantor’s Biology Blog
  4. 4. Discovery of Cells Leeuwenhoek used microscope to look at drops of pond water  Filled with tiny living things  Called them “animalcules” Picture by Lens On Leeuwenhoek
  5. 5. Robert Hooke English physicist Used microscope to observe Picture by History of the Microscope  Flowers  Insects  Spider webs  Slices of cork Picture by Dare To Unravel Concluded  Wood parts of plants had rectangular chambers  Called them cells
  6. 6. Theodor Schwann 1839, German Biologist Picture by Biographical Outlines Found some animal tissues resemble cellular tissue of plants Eventually concluded  Animals are made up of cells Picture by Biographical Outlines
  7. 7. The Cell Theory Robert Brown (Scottish Biologist)  Found object in center of cell (nucleus) Picture by Wikipedia Matthias Schleiden (German Biologist)  Suggested nucleus plays role in cell reproduction Picture by Biographical Outlines
  8. 8. The Cell Theory Rudolf Virchow  1855 German Physician Picture by Wikipedia Proposed that animal and plant cells are produced only by the division of cells that already exist Picture by The Encyclopedia of Science
  9. 9. The Cell Theory  1. All living things are composed of cells  2. Cells are the smallest working units of living things  3. All cells come from preexisting cellsPicture by Mrs. Olsen’s 5th Grade Class Page
  10. 10. Modern Microscopes 1) Compound Light Microscope  Contains more than 1 lens  Magnifies up to 1000 times Parts of Microscope Handout Picture by Wikipedia
  11. 11. Modern Microscopes 2. Electron Microscope  Uses magnets to focus beam of electrons to examine sample  Magnifies 1000 times more than light microscope Picture by Ego TV by UK Electron Microscope Facility
  12. 12. Types of Electron Microscopes Transmission Electron Microscope (TEM)  Sends electrons through sample  Puts image on fluorescent screen Scanning Electron Microscope (SEM)  Electron scans sample’s surface  Puts image on TV screen Picture by Electron Microscope
  13. 13. Electron Microscope Limitations  Sample must be in vacuum  Be nonliving  Samples for TEM need to be thin slices  SEM doesn’t show internal structurePicture by Electron Microscope
  14. 14. Scanning Probe Microscope Trace surface of sample with tiny tip (probe)  Very tiny objects like atoms and molecules Picture by Principles of Scanning Probe Microscopy
  15. 15. 3.2: Cell Boundaries Objectives  1. Discuss the roles of the cell membrane and cell wall  2. Describe passive transport and active transport
  16. 16. Cell Membrane Outer boundary that separates and protects cell from its surroundings  Must allow certain substances to come in  Must allow waste to exit Descried as selectively permeable  “The bouncer” or “Main gate” Picture by The Biology Corner
  17. 17. Lipid Bilayer Cell membrane is made up of lipid molecules  Known as phospholipids Polar end = head (attract water) Nonpolar end = tail (repel water) Picture by
  18. 18. Lipid Bilayer Line up in double-layer pattern  Known as lipid bilayer Lipid Bilayer  Provides cell membrane with tough flexible barrier  Protects cells Picture by
  19. 19. Other Cell Membrane Components Most cell membranes have proteins in lipid bilayer  Have carbohydrates attached Protein purpose  Move material across cell membrane Picture by Cell Membrane Wiki  Protect membrane  Carbohydrates act as “ID” cards
  20. 20. Cell Wall Porous membrane located outside cell membrane  Found in plant cells, algae, and bacteria  NOT found in animal cells Supports and protects cells  Allow substance to pass in and out Made of:  Carbohydrates called cellulose  Give plants their strength  Proteins Picture by Molecular Expressions
  21. 21. Passive Transport Process of moving substances in and out of a cell  Does NOT use energy Picture by Cell Organization & Functions
  22. 22. Diffusion Process by which substances spread through a liquid or gas  Move from region of high concentration to area of low concentration  Example: food coloring in water In cells…  Liquids and small lipids diffuse directly across cell membrane Picture by Biology Corner
  23. 23. Facilitated Diffusion  Cell membrane also contains protein channels  Allows larger substance to pass through  Facilitated Diffusion  Diffusion that occurs with the aided help of a protein channel  Each protein channel is specified for a certain substancePicture by Our Virtual Classroom
  24. 24. Osmosis The diffusion of water through a selectively permeable membrane Water diffuses from areas of high concentration to areas of low concentration Picture by Free Drinking Water
  25. 25. Osmotic Pressure When water moves by osmosis, it produces pressure  Enough to destroy cell Three ways to control:  1) cell wall  2) pump out water  3) bathe cells in blood Picture by Non Ideal Solutions
  26. 26. Osmotic Pressure Cell Wall  Strong tough wall prevents cell from expanding  Counter acts osmotic pressure Pump Out  Cells use contractile vacuole to pump out water Picture by Non Ideal Solutions
  27. 27. Osmotic Pressure Bathe Cells in Blood  Mostly in large animals  Blood cells have same concentration of dissolved substances  Help absorb excess water Picture by A Sweet Life
  28. 28. Active Transport Movement of a substance against a concentration difference Requires A LOT of energy  Transports:  Large molecules  Food  Whole cells Picture by G11-BioA -2011
  29. 29. 3.3: Inside The Cell Objectives  1. Describe the composition and function of the nucleus  2. List and describe the organelles of the cytoplasm  3. Interpret the changes observed when a paramecium takes in food
  30. 30. Nucleus  Large, dense structure contained in cells  Known as control center  “Main office of factory”Picture by Plant Cell
  31. 31. Nucleus Organisms can be classified into 2 categories  1. Eukaryotes  Organisms cells HAVE nuclei  Include unicellular and multicellular  2. Prokaryotes  Organisms that do NOT contain nuclei  Small single celled organisms Picture by Bacterial/Prokaryotic Phylogeny
  32. 32. Role of Nucleus Contains nearly all of cell’s DNA  Has instructions to make proteins / molecules  Form material called chromatin  Spreads through nucleus When cell divides  Chromatin condense into chromosomes  Acts as “blueprint of factory” Picture by Animal Port
  33. 33. Structures In The Nucleus Nucleolus  Small dense region inside nucleus  Where ribosomes are made Picture by Molecular Expressions Nuclear Envelope  Membrane that surrounds the nucleus  Has pores to transport materials in and out
  34. 34. Cytoplasm Fluid outside nucleus held in by cell membrane  Holds all other cell organelles  These are small structures that perform specialized functions in the cell  Allows for movement Known as the “factory floor” Picture by Daylilies
  35. 35. Ribosomes  Tiny particles made of RNA and protein  Site for protein synthesis  Gets instructions from nucleus  Known as “the workers”Picture by Cellupedia
  36. 36. Endoplasmic Reticulum (ER)  Processing and transporting of proteins and other macromolecules  Network of membranes  2 types  1. Smooth ER… NO ribosomes attached to surface  2. Rough ER… ribosomes attached to surface  Act as the subwayPicture by Molecular Expressions
  37. 37. Golgi Apparatus  Act as packaging center  Modify and add components to proteins  Attach carbohydrates or lipidsPicture by Molecular Expressions
  38. 38. Lysosomes  Sac-like membrane that gets rid of waste  Filled with chemicals and enzymes  Can also break down and gets rid of damaged organelles  Known as the “garbage man”Picture by Molecular Expressions
  39. 39. Cytoskeleton Act as a supporting framework for cell  Found in eukaryotic cells Components  Microtubules  Mircofillaments Picture by Cellupedia  These are hollow tubes of protein that provide framework to support cell
  40. 40. Vacuoles Sac-like structure used for storage  Animals  Store proteins, fats, and carbohydrates  Plants  Store water and dissolved salts  Provide support  Known as “the warehouse” Picture by Molecular Expressions
  41. 41. Mitochondria Produces energy from a chemical fuel  Organic molecules like glucose or other sugars Found in eukaryotic cells  Plants and animals Contain own DNA Picture by Molecular Expressions Known as “powerhouse of cell”
  42. 42. Chloroplasts Organelle that produces energy from sunlight  Found in plants ONLY and some algae Aids in the process of photosynthesis Green due to chlorophyll pigment Also contains own DNA Picture by eTeaching Program
  43. 43. 3.4: The Origin of the Eukaryotic Cell Objectives  1. Define the endosymbiont hypothesis
  44. 44. Eukaryotic vs. Prokaryotic  Eukaryotes  Prokaryotes  Nuclues  Have NONE of these  Mitochondria  Chloroplasts  Other organelles  WHY???Picture by BioCoach Activity
  45. 45. The Work of Lynn Margulis Focused on mitochondria and chloroplasts  Used on DNA to make compounds  Both surrounded by two membranes  Both reproduced separately from rest of cell  Mitochondria from mitochondria  Chloroplasts from chloroplasts  Why did this happen??? Picture by The Alien Next Door Blog
  46. 46. The Endosymbiont Hypothesis Billions of years ago…  Eukaryotic cells arose as a combination of different prokaryotic cells  Cells consumed other cells but still each survivedPicture by Molecular Expressions
  47. 47. Margulis’s Model  Stated mitochondria and chloroplasts had ancestors that were free-living organisms  Were consumed by larger cells  Became organelles in larger cellsPicture by The Endosymbiotic Hypothesis
  48. 48. Further Evidence Chloroplast DNA  Similar to DNA in prokaryotic cells In Mitochondria & Chloroplasts  Contain own ribosomes to make own proteins  Ribosomes similar to prokaryotic ribosomes Picture by Molecular Expressions