CHAPTER 7: A VIEW OF THE CELL THE DISCOVERY OF CELLS!! ▸ 1.THE FIRST MICROSCOPIST: ▸ ANTHON VAN LEEUWENHOEK –A. MID 1600'S –B. HIS MICROSCOPE HAD ONE LENS –C. IT USED NATURAL LIGHT –D. HE WAS THE FIRST TO OBSERVE LIVING THING S IN WATER!

2. ROBERT HOOKE - NAMED CELLS ▪A. HE LIVED AT THE SAME TIME AS VAN LEEVWENHOEK! ▪B. HIS MICROSCOPE WAS COMPOUND, WITH 2 OR MORE LENSES. ▪C. HE OBSERVED CORK - THE DEAD CELLS OF OAK BARK. ▪D. THE SHAPE OF THE CORK PARTS REMINDED HIM OF THE SMALL ROOMS THAT MONKS LIVED IN AT THE MONASTERY. ▪E. HOOKE NAMED THE SHAPES “CELLS”

3. MATTHIAS SCHLEIDEN ▪A.OBSERVED MANY PLANTS MICROSCOPICALLY ▪B. CONCLUDED “ALL PLANTS” ARE MADE OF CELLS ▪4. THEODORE SCHWANN ▪A. OBSERVED MANY ANIMALS MICROSCOPICALLY ▪B. CONCLUDED “ALL ANIMALS” ARE MADE OF CELLS

5. ROBERT BROWN ▪A. DISCOVERED THE CELL NUCLEUS ▪B. THE NUCLEUS WAS DISCOVERED IN RUDOLPH VIRCHOW ▪A. DECIDED THAT THE NUCLEUS WAS RESPONSIBLE FOR CELL DIVISION ▪B. CONCLUDED “ALL CELLS COME FROM OTHER LIVING CELLS”

THE CELL THEORY ▪1. ALL ORGANISMS ARE MADE OF ONE OR MORE CELLS! ▪2. THE CELL IS THE BASIC UNIT OF ORGANIZATION ▪3. ALL CELLS COME FROM PRE-EXISTING CELLS

TYPES OF MICROSCOPES A. COMPOUND LIGHT MICROSCOPES ▪1. USED TO VIEW SINGLE CELLS OR SLICED & STAINED PARTS OF CELLS ▪2. MAGNIFIES ABOUT 1500 TIMES ▪3. TWO OR MORE GLASS LENSES ARE USED TO MAGNIFY OBJECTS

B. PHASE CONTRAST MICROSCOPE ▪1. BEST TO SEE INSIDE LIVING CELLS ▪2. 3-D EFFECT GIVES DEPTH TO OBJECTS ▪ MAGNIFICATIONS POSSIBLE

SCANNING ELECTRON MICROSCOPE ▪1. SHOWS A 3-D IMAGE OF THE SURFACE OF OBJECTS (LIKE CELLS) ▪2. MAGNIFIES FROM 60,000 TO 500,000 TIMES! ▪3. USES A BEAM OF ELECTRONS TO SWEEP OVER THE SURFACE OF CELLS!

TRANSMISSION ELECTRON MICROSCOPE ▪1. A BEAM OF ELECTRONS MUST PASS THROUGH SPECIMENS ▪2. THIS PROVIDES A 2-D IMAGE ONLY ▪3. IT IS USED TO STUDY SLICED & STAINED CELL PARTS & OBJECTS ▪4. 500,000 MAGNIFICATIONS ARE POSSIBLE!

SCANNING TUNNELING MICROSCOPE ▪1. CREATES A 3-D IMAGE BY USING A STREAM OF ELECTRONS TO MAP THE CONTOUR OF THE ATOMS ON AN OBJECT’S SURFACE. ▪2. DYES CAN ALSO BE ADDED TO SOME PARTS OF THE OBJECT. THIS NEW TECHNIQUE ENHANCES OUR ABILITY TO EXAMINE THESE SUPER SMALL IMAGES.

TWO BASIC CELL TYPES ▪PROKARYOTES: –1. LACK INTERNAL MEMBRANE BOUND STRUCTURES –2. NO NUCLEAR MEMBRANE –3. EXAMPLES: BACTERIA & CYANO (BLUE-GREEN) BACTERIA

EUKARYOTE: ▪1. CONTAIN INTERNAL MEMBRANE BOUND STRUCTURES, SUCH AS A NUCLEUS & MITOCHONDRIA! ▪2. ANIMAL CELLS, PLANT CELLS, PROTIST CELLS, & FUNGI CELLS ARE ALL EUKARYOTIC!

THE PLASMA MEMBRANE: BOUNDARY BETWEEN THE CELL & ITS ENVIRONMENT! ▪1. IT CONTROLS ENTRY OF GLUCOSE, AMINO ACIDS, LIPIDS, ETC. ▪2. IT KEEPS OUT HARMFUL STUFF! ▪3. IT REMOVES EXCESS IONS, ETC.! ▪4. IT IS SELECTIVELY PERMEABLE!

PLASMA MEMBRANE STRUCTURE A PHOSPHOLIPID BILAYER ▪TWO LAYERS OF PHOSPHOLIPID MAKE A SANDWICH WITH THE FATTY ACID TAILS FORMING THE INTERIOR OF THE MEMBRANE. ▪ PHOSPHOLIPID HEAD ▪ FATTY ACID TAIL▼ ▪ FATTY ACID TAIL ▲ ▪ PHOSPHOLIPID HEAD

▪WITH THE PHOSPHOLIPID ON THE OUTSIDE & THE FATTY ACID ON THE INSIDE THE BARRIER IS WATER SOLUBLE ON THE OUTSIDE & WATER INSOLUBLE IN THE MIDDLE! ▪WATER SOLUBLE MOLECULES WILL NOT EASILY MOVE THROUGH THE PLASMA MEMBRANE BECAUSE THEY ARE STOPPED BY THE WATER INSOLUBLE MIDDLE LAYER!

THE FLUID MOSAIC MODEL ▪1. THE MEMBRANE IS FLEXIBLE! ▪2. PHOSPHOLIPID MOVE WITHIN THE MEMBRANE LIKE WATER MOVES IN THE CURRENTS OF A LAKE! ▪3. PROTEINS IN THE MEMBRANE MOVE AMONG THE PHOSPHOLIPID LIKE BOATS WITH THE DECKS ABOVE WATER & THE HULL BELOW WATER! ▪4. THE PROTEINS CREATE A“MOSAIC” OR PATTERN ON THE MEMBRANE’S SURFACE

▪CHOLESTEROL: ▸ 1. IS FOUND IN THE PLASMA MEMBRANE ▸ 2. IS CRITICAL IN THE STABILITY OF THE PLASMA MEMBRANE ▸ 3. PREVENTS FATTY ACID CHAINS IN THE MEMBRANE FROM STICKING TOGETHER

PROTEINS ▪1.SPAN THE ENTIRE MEMBRANE CREATING SELECTIVE PERMEABILITY ▪2.THESE PROTEINS ARE TRANSPORT PROTEINS THAT ALLOW NEEDED MATERIALS OR WASTES TO MOVE THROUGH THE PLASMA MEMBRANE! ▪3.OTHER PROTEINS & CARBOHYDRATES STICK OUT FROM THE SURFACE & HELP CELLS IDENTIFY EACH OTHER ▪4.THIS IS IMPORTANT IN PROTECTING YOUR CELLS FROM INFECTION!

EUKARYOTIC CELL STRUCTURE ( CELL PARTS FOR YOU TO LEARN ! ) ▪1. CELL WALL ▪2. PLASMA MEMBRANE/ CELL MEMBRANE ▪3. NUCLEUS ▪4. NUCLEOLUS ▪5. CHROMATIN ▪6. DNA ▪7. CHROMOSOMES

( CELL ORGANELLE’S CONTINUED ) ▪8. RIBOSOMES ▪9. CYTOPLASM ▪10. ENDOPLASMIC RETICULUM ▪11. GOLGI APPARATUS ▪12. VACUOLE ▪13. LYSOSOME ▪14. PLASTIDS ▸ A. CHLOROPLAST ▸ B. CHROMOPLAST ▸ C. LEUCOPLAST

( CELL ORGANELLES CONTINUED ) ▪15. MITOCHONDRIA ▪16. CYTOSKELETON ▸ A.MICROTUBULES ▸ B.MICROFILAMENTS ▪EACH ORGANELLE HAS IMPORTANT FUNCTIONS TO TAKE CARE OF IN THE CELL. THEY ENABLE EACH CELL TO CARRY OUT ALL OF THE FUNCTIONS OF LIFE !

COMPARING PLANT & ANIMAL CELLS ▪PLANT CELLS HAVE: ▪A CELL WALL ▪CHLOROPLASTS & ▪USUALLY ONLY ONE VERY LARGE WATER VACUOLE !

▪ANIMAL CELLS: ▪THE CENTRIOLE IS THE ONLY ORGANELLE UNIQUE TO ANIMAL CELLS ▪ANIMAL CELLS TYPICALLY HAVE MANY SMALL VACUOLES ▪ALL OTHER ORGANELLES ARE FOUND IN BOTH PLANTS & ANIMALS !