Which one is the prokaryotic cell? What makes prokaryotic cells different from Eukaryotic cells?

How can we see the parts of a cell How can we see the parts of a cell? Some organelles can be seen by looking through a compound light microscope while other need a higher power microscope to observe. Which organelles do you only find in plant cells Which organelle is larger in a plant cell than in an animal cell?

History of the microscope Sci Show https://www.youtube.com/watch?v=Ue-86MDmjns 5 min

Organelles that can be seen with a light microscope

Observing Very Small Living Things The microscope is used by scientists to observe very small unicellular and multicellular living things. There are many different types of microscopes. a magnifying lens a compound light microscope electron microscopes scanning electron microscope (SEM) See page 11 Water flea (Daphnia) (c) McGraw Hill Ryerson 2007

(c) McGraw Hill Ryerson 2007 Early Microscopes First light microscope invented in 1590’s by Zacharias Jansen put several lenses in a tube and made a very important discovery.. The microscope is used by scientists to observe very small unicellular and multicellular living things. Early microscopes were built in the late 1600’s. The history of the microscope begins with Zacharias Jansen's invention of the first light microscope in the 1590's. Anton van Leeuwenhoek later made significant improvements to the compound microscope. (c) McGraw Hill Ryerson 2007

Anton van Leeuwenhoek Was the first man to make and use a real microscope in 1666. His microscopes had a single lens and were hand- held. He could magnify up to 250x, and used it to observe microscopic living things. Van Leeuwenhoek discovered "protozoa" - the single- celled organisms and he called them "animalcules” First to observe red blood cells and sperm

Microscopes Wacky History of the Cell video

Compound Light Microscope The compound light microscope has two sets of lenses that magnify an image. Each of the objective lenses has a different magnification power. Low power = 4x objective Med power = 10x objective High power = 40x objective Multiply the objective by the eyepiece for total magnification. Example: High Power = 40 x 10 = 400 x Do you know all the compound microscope parts? See pages 12-13 (c) McGraw Hill Ryerson 2007

Electron Microscope uses beams of electrons instead of rays of visible light to form highly magnified images of tiny areas materials or biological specimens. It is capable of much higher magnifications and has a greater resolving power than a light microscope, allowing it to see much smaller objects in finer detail. Magnification up to 10,000,000x

How the Compound Light Microscope works Use your text book to label the parts and their functions Do you know all the compound microscope parts? See pages 12-13 (c) McGraw Hill Ryerson 2007

Label

Proper Handling of a Microscope Always use 2 hands: One hand on the arm, one hand supporting the base

Using a light microscope Always start and end your microscope session by placing the lowest power objective lens in position. Place slide on the stage, secure with clips. Looking from the side, turn the coarse focus knob until it is close to the slide. You may have to move the slide around on the stage of the microscope to bring the specimen into the viewing area. Once object is located and in focus, you may move to higher objective. Only use fine focus knob when using highest power objective. Use lowest objective first: Find your object, get it into focus without cracking slid

Why do we need to start with the lowest objective first? The lowest object makes it is easier to locate the specimen on the slide than if you start with a higher power objective. To calculate the power of magnification of a microscope simply multiply the magnification of the ocular lens and the magnification of the objective lens.

Practice Using letter “e”, bits of yarn, feather, colored magazine paper. Students learn handling, focusing, navigating, switching to higher power, noticing difference of size in FOV under different magnification. Using letter “e”, bits of yarn, feather, colored magazine paper. Students learn handling, focusing, navigating, switching to higher power, noticing difference of size in FOV under different magnification.

Field of View (FOV) The diameter of the circle of light that you see when looking into a microscope.  As the power gets greater, the image gets larger and the field of view gets smaller.  

Calculating Field of View (FOV) Your can determine field of view by placing a clear metric ruler on the stage and counting the millimeters from one side to the other. 

Using FOV to determine approximate size of an object. For the diagram on the right, If each line represents 1 mm, how big is the bug? For the diagram on the right, If each line represents 1 mm, how big is the bug?

Using FOV to determine approximate size of an object. If the Field of View is 2mm, how big is the cell?

How many? Cm in 4 meter? Cm in 4000 mm? Millimeters in 40 cm?

Magnification The compound light microscope has two sets of lenses that magnify an image. The image you observe is upside, backwards, and magnified. Magnification: Each of the objective lenses has a different magnification power. Low power = 4x objective Med power = 10x objective High power = 40x objective

Calculating Total Magnification Eye Piece (10x) X Objective (4x, 10, 40x) Example: High Power = 40 x 10 = 400 x

Resolving Power Resolving power is the ability to distinguish between very small objects that are very close together. Magnification is the ability to make small objects seem larger, such as making a microscopic organism visible. Resolution is the ability to distinguish two objects from each other. Light microscopy has limits to both its resolution and itsmagnification. The human eye has a certain resolving power. You can see the individual dots in diagrams A, B and C. The human eye does not have the resolving power to see the dots in diagram D. Can you think of ways to increase resolving power?

Preparing a Wet Mount of a Specimen In a wet mount the specimen is suspended in a drop of water on the microscope slide and then covered with a coverslip (smaller sheet of glass or plastic). The cover glass/slip is needed to protect the microscope's objective lens from contacting the specimen. Wet mounts are used to view microscopic organisms that grow in pond water or other liquid media, especially when studying their movement and behaviour.

Preparing a Wet Mount of a Specimen Place specimen on a clean microscope slide. Using a dropper, place one drop of water on the slide. Take cover slip, hold at a 45 degree angle to the slide and slowly lower it until the specimen is covered. This prevents bubbles.