Transcript Microscopes
Microscopes Objectives • Relate advances in microscope technology to discoveries about cells and cell structure • Compare the operation of a compound light microscope with that of an electron miroscope • Identify the main ideas of the cell theory Before Microscopes • Before microscopes people believed that diseases were caused by curses and supernatural spirits. MICROSCOPE • Microscope tool used to look at small organisms (microorganisms) MICROSCOPE • “Micro” = small • “Scope” = to look at MICROSCOPES ALLOW US TO SEE CELLS Cell basic unit of life Plant cell Animal cell Kinds of Microscopes • 3 Major kinds of microscopes 1. Simple Light Microscope 2. Compound Light Microscope 3. Electron Microscope Simple Light Microscope 1. Simple Light – 1st type invented (1500’s) • 1 Lens • Energy Source = Light • Low Magnification power Compound Light Microscope 2. Compound Light – 2+ Lenses – Energy Source = Sunlight or Electricity – Up to about 1500 x’s actual size Can you find the differences between simple and compound? Magnification TOTAL MAGNIFIATION = (lens) X (objective) lens = 10X objective = 4X (multiply) Total Magnification = (10) X (4) = 40 X’s actual size • What is the total magnification of a microscope with an objective of 10x? Electron Microscopes Electron Microscopes • • Light Source = beam of electrons Magnify up to 500,000 X’s actual size Electron Microscopes 2 kinds of electron microscopes: SEM TEM •Scanning Electron Microscope •Transmission Electron Microscope •surface •inside MAJOR DISADVANTAGE : KILLS SPECIMEN Taken by a S.E.M. Can you guess what this is? It was taken by a T.E.M. Carrying a Microscope • • • • CAREFULLY!!!! They are expen$ive!! One hand on ARM Other hand on BASE Microscope Label • Turn to page 1070 in your book • Label your microscope worksheet • Write down vocab on back of paper Important Scientists ONCE UPON A TIME in the mid 1600’s… • Anton van Leeuwenhoek – first microscope (single lens, used light to see object) • Robert Hooke – named cells – looked at dead oak bark (cork), saw small chambers like rooms in a monastery – Coined the term “cell” More Important Scientists •Schleiden – all plants made of cells •Schwann – all animals made of cells Schwan sounds like swan (an animal) • Brown – some cells contain a “prominent structure” (aka nucleus) • Virchow – Brown’s “structure” (aka nucleus) is responsible for cell division Cell • Cell – basic units of living things atomsmake up moleculesmake up organellesmake up cells make up tissues make up organs make up organ systems make up Organisms (LIKE YOU!) IS AN ORGANELLE A LIVING ORGANISM? The Summary of all these Ideas led to the… Cell Theory • 1. All organisms are composed of one or more cells • 2. The cell is the basic unit of living organisms • 3. All cells come from preexisting cells Quick Project: Cell Theory Foldable • Make a tri-fold in a piece of paper • Label each section with a PART of the cell theory… • Explain each part of the cell theory using a PICTURE… • Be sure to include any important scientists in your drawings where appropriate! • You may use words to explain your picture, but the picture should do “most of the talking,” if you know what I mean… Cells are made up of ORGANELLES • Organelles = specialized structures that have a specific function in the cell 2 Types of Cells • 2 kinds of Organelles and 2 kinds of CELLS Prokaryotic Cells Eukaryotic Cells Eukaryotic Cells – Membrane-bound organelles – Have nucleus – Most come from multicellular (plants/animals) – Can be unicellular (some protists – ameba & paramecium) – Larger Prokaryotic – No nucleus – No membrane-bound organelles – Contain Ribosomes – Single celled organisms (usually) – Smaller (usually) – Round DNA/RNA called Plasmids – Example: bacteria Plant cell vs. Animal cell Plant cell Animal cell What differences do you see? Plant cell Animal cell Plants vs. Animal • Plants contain: – – – – Cell wall Chloroplast Large vacuoles Some animal cells contain vacuoles – smaller & more numerous – Why do plants need LARGE vacuoles? Plants vs. Animal • Animal cells contain: – NO cell wall (only membrane) – Small vacuoles – Why would an animal only need SMALL vacuoles? Organelle Animal Cell Plant Cell Shape: Round (irregular shape) Rectangular (fixed shape) Golgi apparatus: Present Present Cilia: Nucleus: Mitochondria: Cytoplasm: Present Present Present Present Chloroplast: Cell wall: Plasma Membrane: It is very Rare Present Present Present Plant cells have Animal cells don't chloroplasts because have chloroplasts they make their own food None Yes cell wall and a cell only cell membrane membrane Animal Cell Organelle Plant Cell May be found in some cells Lysosomes occur in cytoplasm. Present May be found in some cells Lysosomes usually not evident. Present Endoplasmic Reticulum (Smooth and Rough): Present Present Vacuole: One or more small vacuoles (much smaller than plant cells). One, large central vacuole taking up 90% of cell volume. Centrioles: Present in all animal cells Only present in lower plant forms. Flagella: Lysosomes: Ribosomes: