2. A.Base B.Pillar C.Arm D.Stage E.Slide F.Cover slip G.Stage clip H.Light source I.Low power objective lens J.High power objective lens K.Body tube L.Ocular (eyepiece) M.Coarse adjustment knob N.Fine adjustment knob O.Nosepiece P.Diaphragm

3. Chapter 7: Cells

4. Microscopes Magnification – increase of an object’s apparent size Total magnification – mag. of eyepiece x mag. of objective lens Ex: (10X) x (4X) = 40X Resolution (resolving power) – the distance needed to distinguish 2 points as separate Types of microscopes: compound light, transmission electron, scanning electron

5. Compound light microscope: Specimen is enlarged as light passes through set of glass lenses Magnification – up to 2000X Resolving power – up to 200nm Can be used to view living specimens

7. Transmission electron microscope: Electrons passing through a specimen are brought into focus by a set of magnetic lenses Image is projected onto a fluorescent screen or photographic film; flat image Magnification – up to 500,000X Resolving power – 0.2nm Cannot be used to view living specimens

9. Scanning electron microscope: A narrow beam of electrons is scanned over the surface of the specimen, which is coated with a thin layer of metal Metal gives off secondary electrons, which are collected to produce a picture of the specimen on the screen Magnification – up to 100,000X Resolving power – 1 nm Cannot view living specimen; 3D image

11. http://remf.dartmouth.edu/imagesindex.html Microscope images:

12. The Cellular Level of Organization Living things are made of cells. Living things may be unicellular or multicellular. Cells can be prokaryotic or eukaryotic Cell structure is diverse (different shapes & sizes based on jobs) but all cells share common characteristics. Organelles – tiny specialized structures performing specific cellular functions

13. First cells observed in 17 th century by Anton van Leeuwenhoek Term “cell” coined by Robert Hooke - observing cork cells, reminded him of cells (rooms) in a monastery. Observations by Matthias Schleiden, Theodor Schwann, and Rudolf Vichow contributed to the development of the cell theory.

14. The cell theory states: 1.All organisms are composed of one or more cells. 2.Cells are the basic unit of structure and function in organisms. 3.All cells come only from other cells.

15. Sizes of living things

16. Prokaryotic cells Include the bacteria and archaea; adapted to live anywhere. Outer Boundary: Cell wall & plasma membrane –In some cells, wall is surrounded by a capsule or slime layer Cytoplasm: Ribosomes, enzymes, & thylakoids (in Cyanobacteria only – for photosynthesis) Nucleoid: Region (not bound by a membrane) where DNA is found on a single chromosome

17. Plasmids – small accessory rings of DNA that may be found in bacterial cells Most bacteria have flagella composed of the protein flagellin - for movement Some also have fimbriae (short appendages) that help cells attach to surfaces. Bacteria have a great metabolic diversity –Can use any type of organic matter for nutrients –Are able to synthesize any needed molecules given an energy source

20. Prokaryotes vs. eukaryotes ProkaryotesEukaryotes OrganismsBacteriaProtists, Fungus, Plants, & Animals NucleusNoYes Cell wall/membraneYes RibosomesYes Other organellesNoYes CytosolYes

21. ProkaryotesEukaryotes Cilia or flagella Yes DNASingle loop in nucleiod In nucleus Cell specialization NoIf multicelled

22. Evolution of the Eukaryotic Cell Organelles like nuclear envelope, ER, & golgi apparatus may have appeared when plasma membrane folded inward Endosymbiotic theory: eukaryotes arose from a symbiotic relationship between various prokaryotes. Flagella, mitochondria & chloroplasts were taken in by a larger cell, yet not destroyed. Symbiotic relationship would have been established within that larger cell (a eukaryotic cell)

23. -Spirochete would become flagellum -Heterotrophic bacteria became mitochondria. -Cyanobacteria became chloroplasts. -Would explain the following about mitochondria & chloroplasts: Similarity to bacteria in size & structure Double membrane surrounding them Small amount of DNA found inside each Each contain own ribosomes resembling those of bacteria RNA base sequence of their ribosomes suggests prokaryotic origin

24. Evolution of the eukaryotic cell

25. Eukaryotic cells Have a nucleus that controls all cell activities. Contain many cell organelles that perform specific jobs. Organisms in the following kingdoms are eukaryotic: Protists, Fungus, Plants, and Animals

26. Plasma (cell) membrane – A Nucleus* Nuclear membrane – B Nuclear Pore – C Nucleolus – D Chromatin – E Cytoplasm* Cytosol – F Mitochondria – G Golgi apparatus – H Centriole – I Cytoskeleton* Microtubules – J Microfilaments – N Vacuole – K Lysosome – L Ribosome – O Endoplasmic reticulum* Rough ER – Q Smooth ER - P

29. Plasma (cell) membrane – A Cell wall – B Cytoplasm* Cytosol – C Vacuole – D Chloroplast – F Golgi apparatus – I Ribosome – J Endoplasmic reticulum* Rough ER – K Smooth ER – T Mitochondria Cytoskeleton* Microtubules – M Microfilaments – N Lysosome – O Nucleus* Nuclear membrane – R Nuclear pores – S Nucleolus (not shown) Chromatin (not shown)

32. Plasma membrane: Surround all cells Made of phospholipids and proteins. Regulates what materials enter & leave cell

33. Cell wall: –Found in plant cells in addition to the plasma membrane. –Protects and supports the cell Cytoplasm – area between the nucleus and the plasma membrane –Contains all cell organelles Cytosol - The fluid in-between the organelles

34. Structure of the Nucleus Nucleus: stores genetic information and controls metabolic activities Nucleus contains the following: Chromatin Nucleoplasm Nucleolus Nuclear envelope Nuclear pores

35. Chromatin: DNA and protein Will coil to form chromosomes just before cell division Nucleoplasm: semifluid material inside the nucleus Nucleolus: Darkened region in chromatin Makes ribosomal RNA, which will leave nucleus to form ribosomal subunits in cytoplasm Nuclear envelope: Double membrane around nucleus Nuclear pores: openings in nuclear membrane to allow proteins into the nucleus and rRNA out of the nucleus

36. Nucleus and nuclear envelope

37. Ribosomes Location where protein synthesis occurs Ribosomes are composed of a large subunit and a small subunit. Where ribosomes can be found: –alone in the cytoplasm –in groups called polyribosomes –attached to the endoplasmic reticulum ER with ribosomes is called rough ER

38. Ribosomes in cytoplasm: Proteins made here are used by cell at structures such as mitochondria and chloroplasts Ribosomes on ER: Proteins made here are eventually sent out from cell or become part of cell membrane

39. Ribosomes on ER

40. The Endomembrane System Consists of : –Nuclear envelope –Endoplasmic reticulum (ER) –Golgi apparatus –Vacuoles and Vesicles All parts are connected either directly or through transport vesicles

41. Endoplasmic reticulum System of membranous channels and saccules (flattened vesicles). Rough ER - has ribosomes –Makes proteins that will be used outside of the cell. Smooth ER - lacks ribosomes –Site of synthesis of complex carbohydrates and lipids, including phospholipids –Packaging of proteins into vesicles and transported to golgi apparatus

42. The endoplasmic reticulum

43. Golgi apparatus Consists of a stack of curved saccules (often compared to stack of plates). Receives vesicles (containing protein and lipids from the smooth ER) Packages, processes, and distributes them within the cell. Also involved in secretion – send vesicles to plasma membrane where contents are released Involved in formation of lysosomes.

44. The Golgi apparatus

45. Vacuoles and vesicles Both are membranous sacs in the cell that store substances Vacuoles are large; vesicles are small Much larger in plants than in animals Plant vacuoles are typically filled with fluid to give the cell added support – water, sugars, salts, pigments (for color of flowers) & toxins (for protection) In protists – contractile vacuoles pump out excess water and digestive vacuoles break down nutrients

46. Lysosomes Vesicles produced by the Golgi apparatus. Contain enzymes. Involved in intracellular digestion (even digesting worn-out cell parts). When cells bring in macromolecules by vesicle formation at plasma membrane, vesicle fuses to lysosome and contents are digested

47. Energy-Related Organelles Chloroplasts – use solar energy to make sugars - photosynthesis Mitochondria – break down sugars to produce ATP – cellular respiration

48. Chloroplasts Belong to group of organelles called plastids Found in plant cells Structure: –Surrounded by two membranes –Stroma - a fluid that contains enzymes. –Thylakoids – sacs/discs inside the stroma that contain chlorophyll (absorbs solar energy) –Grana - stacks of thylakoids

49. Chloroplast structure

50. Other examples of plastids: Amyloplasts – found in roots; store starch Chromoplasts – found in leaves; contain orange & red pigments Elaioplasts - storage organelles of plants that produce oils. Leucoplasts - basically colorless & may not have specific functions. Etioplasts - develop when plants are grown in the dark and have no chlorophyll; will become fully functional chlorplasts with chlorophyll when exposed to light. ****Don’t need to know any of these!!!****

51. Mitochondria Found in plant and animal cells. Structure: –Surrounded by a double membrane –Matrix – fluid that contains enzymes –Cristae – folding of inner membrane – increases surface area - increases space on which cellular respiration can occur

52. Mitochondrion structure

53. Photosynthesis Only occurs in plants, algae, and cyanobacteria Solar energy + carbon dioxide + water  carbohydrate + oxygen Cellular Respiration Occurs in all eukaryotic cells Carbohydrate + oxygen  carbon dioxide + water + energy

54. Cytoskeleton Network of filaments and tubules that extends from the nucleus to the plasma membrane. Maintain cell shape & cause cell & its organelles to move Constantly changing Contains: –Microfilaments –Microtubules

56. Microfilaments Thin protein threads that help give the cell shape and enable the entire cell or parts of the cell to move Play a structural role in intestinal microvilli Interact with motor molecules, such as myosin - movement

57. Microfilaments

58. Microtubules Long, hollow protein cylinders Form rigid skeleton for the cell Assist in moving substances within the cell Centrosome - microtubule organizing center; controls microtubule assembly

59. Microtubule structure

60. Centrioles Involved in cell division Short cylinders with a 9 + 0 pattern of microtubule triplets. –Ring with 9 sets of triplets & none in the middle

61. Only in animal cells Plants have centrosome, but no centrioles within. Centrosome contains 2 centrioles at right angles to each other Centrosome organizes microtubules within cell Roles in cell: Help in organizing spindle fibers (made from microtubules) Direct organization of microtubules within cilia and flagella.

63. Cilia and flagella Involved in cell movement. Cilia – small, numerous hairs Flagella – large, single hair 9 + 2 pattern of microtubules – 9 sets of doublet microtubules around 2 central single ones Cilia and flagella move when the microtubule doublets slide past one another.

65. Plant vs. animal cells PlantAnimal Cell wallYesNo Plasma membraneYes ChloroplastsYesNo CentriolesNoYes Vacuoles1 large central one Several small ones LysosomesFewermore