2a; cells


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2a; cells

  1. 1. Lecture 2a: Cells Cells
  2. 2. Plasma Membrane <ul><li>Forms the boundary of the cell </li></ul><ul><li>It is the ‘gatekeeper’ for the cell </li></ul>Here is a simple bilayer
  3. 3. Plasma Membrane <ul><li>There are proteins imbedded in the membrane - these are the keymasters </li></ul>
  4. 4. Membrane Proteins <ul><li>There are several different functions that the membrane proteins perform for the cell - write in the definitions! </li></ul><ul><ul><li>Channel </li></ul></ul><ul><ul><li>Transport </li></ul></ul><ul><ul><li>Recognition </li></ul></ul>
  5. 5. Membrane Proteins <ul><li>There are several different functions that the membrane proteins perform for the cell - write in the definitions! </li></ul><ul><ul><li>Receptor </li></ul></ul><ul><ul><ul><li>Signal molecule </li></ul></ul></ul><ul><ul><li>Enzymatic </li></ul></ul><ul><ul><li>Junction </li></ul></ul>
  6. 6. Eukaryotic Cells <ul><li>Have a membrane-bound nucleus </li></ul><ul><li>Organelles </li></ul><ul><ul><li>The ‘organs’ of the cell- the organelles concentrate the molecules needed for various functions in one place </li></ul></ul>
  7. 7. Nucleus <ul><li>Nucleus: where the DNA is, the CEO of the cell </li></ul><ul><li>Chromatin: ‘uncoiled’ DNA- long strands of DNA, what condenses into chromosomes during cell division </li></ul><ul><li>Some RNA and protein are in chromatin too </li></ul>
  8. 8. Nucleus and Ribosomes <ul><li>Messenger RNA (mRNA) takes the genetic information from the DNA to the ribosomes </li></ul><ul><li>mRNA is made in the nucleus </li></ul><ul><li>Ribosomal RNA (rRNA) forms part of the ribosomes </li></ul><ul><li>rRNA is made in the nucleolus </li></ul>
  9. 9. Nucleus <ul><li>The nucleus has a double membrane- the nuclear envelope, with pores that allow various RNA/ proteins in and out. </li></ul>
  10. 10. Anatomy of the Nucleus
  11. 11. Ribosomes <ul><li>The site of protein synthesis - receives mRNA from nucleus </li></ul><ul><li>Has two subunits: large and small </li></ul><ul><li>Some free-floating, some attached to endoplasmic reticulum </li></ul><ul><ul><li>Proteins made on ER move inside it; where finalization takes place </li></ul></ul>
  12. 12. Endomembrane System <ul><li>The membranous parts of the cell that help to organize it </li></ul><ul><li>Includes: nuclear envelope, ER, Golgi appratus, vesicles </li></ul><ul><ul><li>Vesicle: membranous sac </li></ul></ul>
  13. 13. Endoplasmic Reticulum <ul><li>The factory of the cell </li></ul><ul><li>Rough ER: Makes proteins, studded with ribosomes </li></ul><ul><li>Smooth ER: makes lipids, specific to cell type </li></ul><ul><ul><li>ex: smooth ER in testes makes testosterone </li></ul></ul><ul><li>Both make transport vesicles </li></ul>
  14. 15. Golgi Apparatus <ul><li>It is the transport station of the cell </li></ul><ul><li>Receives transport vesicles from ER </li></ul><ul><ul><li>Modifies proteins or lipids </li></ul></ul><ul><li>Sorts and organizes products for shipment, either to cytoplasm or out of the cell </li></ul>
  15. 17. Lysosomes <ul><li>The body’s recycling plant </li></ul><ul><li>Specialized vesicles that digest waste or unused molecules or cell parts </li></ul><ul><li>Contain enzymes </li></ul>
  16. 18. Vacuoles <ul><li>Super-size vesicles with specialized functions </li></ul><ul><ul><li>Water in plant cells </li></ul></ul><ul><ul><li>Color, toxins in plant cells </li></ul></ul><ul><ul><li>Fat cells store lipids in vaculoles </li></ul></ul>
  17. 19. Energy Organelles <ul><li>Chloroplasts: plants </li></ul><ul><li>Mitochondria: plants and animals </li></ul><ul><li>Things common to both: </li></ul><ul><ul><li>Bound by double membrane, then another membrane inside </li></ul></ul><ul><ul><li>Have their own DNA and ribosomes; theory is that they are derived from bacteria that invaded eukaryotic cells </li></ul></ul>
  18. 20. Chloroplasts <ul><li>Chloroplasts: Where plants do their magic! - Turn sunlight into glucose </li></ul><ul><li>This is photosynthesis </li></ul>
  19. 21. Chloroplasts <ul><li>Parts to know: </li></ul><ul><ul><li>Stroma: Inner space - Where enzymes that make glucose are </li></ul></ul><ul><ul><li>Thylakoids: disklike sacs, which when stacked together are called </li></ul></ul><ul><ul><li>Granum - this is where pigments capture sunlight </li></ul></ul>
  20. 23. Mitochondria <ul><li>Very small- but very important! </li></ul><ul><li>Make ATP, the energy molecule, via </li></ul><ul><li>Cellular Respiration </li></ul><ul><li>Can move from place to place as needed </li></ul><ul><li>adenosine triphosphate: ATP </li></ul>
  21. 24. Mitochondria <ul><li>Parts to know: </li></ul><ul><ul><li>Matrix: inner area, contains enzymes to break down carbohydrates </li></ul></ul><ul><ul><li>Cristae: highly folded inner membrane </li></ul></ul><ul><ul><ul><li>Where ATP is actually made </li></ul></ul></ul>
  22. 26. Structure and Motion <ul><li>Cytoskeleton: provides structure </li></ul><ul><ul><li>Microtubules: small hollow cylinders </li></ul></ul><ul><ul><ul><li>Provide structure and pathways </li></ul></ul></ul><ul><ul><li>Intermediate filaments </li></ul></ul><ul><ul><ul><li>Support between nucleus and membrane </li></ul></ul></ul><ul><ul><li>Actin Filaments </li></ul></ul><ul><ul><ul><li>Form a web inside membrane </li></ul></ul></ul>
  23. 27. Structure and Motion <ul><li>Motor Proteins </li></ul><ul><ul><li>Three proteins used: myosin, kinesin, dynein </li></ul></ul><ul><ul><ul><li>Myosin moves entire cell in some way </li></ul></ul></ul><ul><ul><ul><li>Others attach with organelles to move them around the cell </li></ul></ul></ul>
  24. 28. Structure and Motion <ul><li>Cilia and Flagella </li></ul><ul><ul><li>Used to move the entire cell around </li></ul></ul><ul><ul><li>Single-celled organisms </li></ul></ul>
  25. 29. The Outer Layer <ul><li>Cell Wall </li></ul><ul><ul><li>All plant cells have this - where the cellulose is </li></ul></ul><ul><ul><li>Gives the plant its strength, both through structure and by joining to other cells </li></ul></ul>
  26. 30. The Outer Layer <ul><li>Extracellular Matrix </li></ul><ul><ul><li>In animal cells, Provides stucture to animal </li></ul></ul><ul><ul><ul><li>Where you find collagen and elastin </li></ul></ul></ul><ul><ul><ul><li>Can be very strong or rather weak, depending on the tissue </li></ul></ul></ul>
  27. 31. The Outer Layer <ul><li>Junctions </li></ul><ul><ul><li>Adhesion: Creates sturdy but flexible sheet of cells - like in the bladder </li></ul></ul><ul><ul><li>Tight: plasma membranes attach to each other - cells that are barriers </li></ul></ul><ul><ul><li>Gap: allows cells to communicate, it is the joining of two identical membrane channels - what allows heart cells to contract as one unit </li></ul></ul>