2. What is the cell theory? What are the names of those who added to the cell theory? What did each contribute? Cell

3.  What do you know about the cell theory?  Get together with a partner and discuss this question.  Be ready to share what you have discussed!

4. Cell Theory  Robert Hooke (1665) ◦ first discovered and named “cells” ◦ looked at dead cells of a cork plant Cell

5. Cell Theory  Anton van Leeuwenhoek (1674) ◦ built microscopes to study ‘animalcules’ known today as microorganisms ◦ first to see living cells Cell

6. Cell Theory  Matthias Schleiden (1838) ◦ stated all plants are made of cells Cell

7. Cell Theory  Theodore Schwann (1839) ◦ studied human notochord ◦ concluded all animals are made of cells Cell

8. Cell Theory  Rudolph Virchow (1858) ◦ every cell comes from another cell like it. Cell

9. Cell Theory  modern Cell Theory ◦ All living things are composed of cells. ◦ Cells are the units of structure and function in living things. ◦ New cells are produced from pre-existing cells. Cell

10. Basic Cell Structure  Cells can come in 3 shapes 1. Sphere 2. Brick 3. Cube Cell

11. Cell Structure The smallest are bacteria cells The largest is the human egg Cell

12.  Cell Membrane ◦ Encloses cell ◦ Controls the movement of materials into and out of cell  Cytoplasm ◦ Jellylike substance that contains the molecular building blocks (proteins, nucleic acids, minerals, ions, organelles etc.)  Organelles ◦ Structures specialized to perform a distinct cell function

13. Cell Structure  Two types of organisms 1. Unicellular- ex. Bacteria, yeasts, Amoeba 2. Multicellular- some cells are specialized; evolved from unicellular cells Cell

14. Cell Structure  Two Types of Organisms  Prokaryote ◦ No nucleus ◦ No membrane organelles ◦ DNA is in Cytoplasm ◦ Single Celled Organisms (unicellular) Cell

15. Cell Structure  Two Types of Organisms  Eukaryote ◦ Have a nucleus ◦ Genetic Information is located in the nucleus ◦ Have membrane bound organelles ◦ Unicellular or multicellular

16. Evolution of eukaryotic cells Prokaryotes were the 1st to evolve, then eukaryotes Why??

17.  What are the major organelles of a cell?  What function or major role does each organelle play within a cell?

18.  List as many cell organelles that you can think of.  List the major function of each!

19. 1. Cell membrane/Plasma membrane:  Boundary between cell and outside environment  Controls the passage of materials in and out of cell  Double layer of phospholipid (charge phosphate group, glycerol head, fatty acid tail)  Phosphate group and glycerol head are polar and hydrophilic  Fatty acid tail is nonpolar and hydrophobic  Very important properties for transport (we will come back to this very soon)

21. 2. Cell Wall  In plants, algae, fungi, and most bacteria  Strong and rigid  Gives cell protection, support, and shape  Cell walls can adhere to each other for support

22. 3. Nucleus  Storehouse for genetic information  Surrounded by a double layer nuclear envelope  Select molecules can cross this barrier  Also contains the nucleolus  place where ribosomes are made

23.  4. Cytoskeleton  In Eukaryotic cells  Network of proteins  Made-up by 3 types of fibers ◦ Microtubules ◦ Microfilaments ◦ Intermediate filaments

24. Cytoskeleton Microtubules  Stained green  Long, hollow tubes  Gives cell shape  The “track” for organelle movement  Used in cell division to pull DNA Intermediate Filaments  Give cell strength

25. Cytoskeleton Microfilaments  Smallest of the 3  Tiny threads that enable cell to divide  Important roles in muscle cells, as they allow muscles to contract and relax

26. 5. Endoplasmic reticulum (ER)  Thin folded membranes (many creases and folds)  Interior is called the lumen  Many cell processes but mostly protein and lipid synthesis  Rough: ribosomes  Smooth: no ribosomes

27. 6. Ribosomes  Stained red  Site of protein synthesis (transport to lumen if on ER)  Assembled in the nucleus and transported to cytoplasm or on ER  Link amino acids together

28. 7. Golgi Apparatus  From the ER proteins move to the golgi  Here, proteins are sorted, modified, and packaged  Either stored or transported out of cell

29. 8. Mitochondria  Supplies energy to the cell  Two membranes, folded and has a high surface area  Converts food to energy  Have their own DNA and ribosomes  Originally free living prokaryotes?

31. 10. Lysosome  Contain enzymes  Defend cells from bacteria and viruses  Break down damaged or worn out cell parts  Do not know if they are in plant cells  Made in ER and are inactive  Activated and Packaged in Golgi  Bud from vesicles

32. 11. Vacuole  Fluid-filled  Storage of materials needed by cell (water, food, ions, enzymes, etc)  Animals have several small vacuoles  Plants have one large one  largest structure in plant cells  holds fluid that strengthens and supports plant  also can hold toxins, waste, and pigments

33. 12. Chloroplasts  Carry out photosynthesis  Stacked disc shaped structures called thylakoids contain the chlorophyll (light absorbing molecule)  Have own mitochondria and DNA  Free living prokaryote?

34. 13. Centrosome and Centrioles  Centrosome is a small area in cytoplasm that produces microtubules  Has two small structures called centrioles  Cylinder shaped made of microtubules arranged in a circle  Used in cell division  Organize microtubules to form cilia and flagella

35. 14. Flagella  Cell movement  Propels cell like a motor boat

36. 15.Cilia  Cell movement  Small hair like structures  Crawl

37. Evolution of eukaryotic cells Endo-Symbiotic Theory: prokaryotes were once engulfed by other cells, giving rise to eukaryotes. 1. Ex. Mitochondria and Chloroplasts have their own DNA and RNA

38. Evolution of eukaryotic cells mitochondria are the result of endocytosis of aerobic bacteria chloroplasts are the result of endocytosis of photosynthetic bacteria Cell

40. What are the different states of concentration across a membrane? Cell

41.  Brainstorm the following with a partner:  How do cells transport substances in and out of the cell membrane?  Be prepared to share with the class.

42. Fluid Mosaic Model ◦ Cell membrane is fluid, not rigid ◦ Phospholipids can move side to side and slide past each other  membrane constantly moving ◦ 3 main molecules  proteins  carbohydrates  lipids  hydrophilic (water loving) heads  hydrophobic (water fearing) tails

43. Transport Cell

44. Transport  cell membrane ◦ allows for transport of materials into and out of cell Cell

45.  Allows some but not all materials to cross  Maintains homeostasis  Molecules cross in several ways: ◦ Small nonpolar cross easily ◦ Small polar cross with help of proteins ◦ Large cross with help of vesicles

46.  Passive:  Movement of molecules across a cell membrane without energy input from the cell ◦ Diffusion ◦ Osmosis ◦ Facilitated diffusion  Active:  Movement of molecules across a cell membrane by chemical energy ◦ Endocytosis ◦ Exocytosis ◦ Phagocytosis

47. Movement of molecules across a cell membrane without energy input!

48. diffusion ◦ movement of molecules in liquid or gas from a region of higher concentration to lower concentration

49. Diffusion Results In:  equilibrium ◦ state in which concentration is equal in all areas

50. osmosis ◦ movement of water from higher to lower concentration.

51.  osmosis ◦ Can be described in 3 ways: ◦ hypertonic ◦ Hypotonic ◦ Isotonic ◦ Note that we are speaking of solutions in comparison to each other, this requires a point of reference. ◦ Example: You may be taller than ___________

52. ◦ hypertonic  concentration of solute is greater outside cell  Water is more concentrated inside the cell  Water diffuses out of the cell, causing it to shrivel ◦ hypotonic  concentration of solute is less outside cell  Water is more concentrated outside the cell  Water diffuses into the cell  Cell sells

53.  Isotonic ◦ Same concentration inside as outside of cell ◦ Water molecules move in and out of the cell in equal rates ◦ Cell size remains constant

54.  osmosis

56. Get with a partner and answer the following: Which is isotonic, hypertonic, hypotonic?

57. Tugor: the pressure within cells derived from osmotic pressure differences between the inside and outside of the cell causing rigidity.

58.  Osmosis  Complete the following table meaning of name concentration of solute (compared to cell) percent of water (compared to cell) water moves into/out of cell hyper hypo iso

59.  osmosis meaning of name concentration of solute (compared to cell) percent of water (compared to cell) water moves into/out of cell hypermorehigherlowerout of cell hypolesslowerhigherinto cell iso

60.  osmosis meaning of name concentration of solute (compared to cell) percent of water (compared to cell) water moves into/out of cell hypermorehigherlowerout of cell hypolesslowerhigherinto cell isosame both directions

61.  facilitated diffusion ◦ molecules move across membrane with help of transport proteins ◦ Still moving down the concentration gradient, no energy required

62. Movement of molecules across a cell membrane by chemical energy

63.  active transport ◦ uses energy to transport molecules against concentration gradient

64.  active transport ◦ uses energy to transport molecules against concentration gradient

65.  Done with the help of transport proteins, usually called pumps  Low concentration to high concentration!  Maintain Homeostasis

66.  Span the membrane  Change shape when bind to a molecule  Each protein has one or two target molecules  Uses chemical energy: ATP!

67.  endocytosis ◦ engulfing solid particles using the cell membrane

68.  endocytosis ◦ engulfing solid particles using the cell membrane 1. phagocytosis  endocytosis of solid material 2. Pinocytosis  Endocytosis of liquid material

69. Transport  exocytosis ◦ cell secretes large particles via membrane bound sacs Cell