Unit One: Matter and Energy Flow in Cells Biology 20 Unit One: Matter and Energy Flow in Cells Topic Two: The Microscope

Objects that can be observed by the unaided eye

Objects that can ONLY be viewed using a microscope

Introduction The cell is the unit of structure of all living things. Living organisms include: Plants Animals Bacteria Protists Fungi All living things are made of at least ONE cell Hundreds of years ago, no one knew this because cells were too small to be seen with the unaided eye The creation of the MICROSCOPE proved the existence of cells!!!

Microscopes 1.Why do we use microscopes? microscopes magnify objects and make small things appear larger 2.What is the main benefit of using microscopes? - resolution or the ability to see detail 3 main types of microscopes: Light/compound microscope Transmission Electron Microscope (TEM) Scanning Electron Microscope (SEM)

3. How do we calculate the total magnification of an object using a light microscope? Total magnification = magnification of ocular lens x magnification of the objective lens Ocular Lens 10X Total mag. = 10 x 40 = 400 times Objective Lens 40X

1. Light Transmission Microscope Total Magnification: 1000X The image is produced by light passing through the specimen The qualities of the image produced are: color and 2-D

Light Transmission Microscope Advantages of the light microscope include: color image living material may be used Disadvantages include: low magnification poor resolution at higher magnifications as the light rays are bent (large images but little detail) Amoeba moving video http://www.youtube.com/watch?v=7pR7TNzJ_pA&feature=related&safety_mode=true&persist_safety_mode=1&safe=active

Scanning Electron Microscope

Scanning Electron Microscope TotalMagnification: 500,000X Scans the surface of the specimen The image is produced by Electrons reflected off the surface Often coat specimen with gold for a sharper image

Scanning Electron Microscope The qualities of the image are: 3D, black and white picture of the surface of the specimen. Advantages: high magnification 3D image that can be easily understood Disadvantages: specimen must be dead

Transmission Electron Microscope Phillips CM 10 TEM Mitochondrion image taken by a TEM

Transmission Electron Microscope Total Magnification: 1,000,000X The image is produced by electrons passing through the specimen shorter wavelength than visible light less scatter - sharper image Qualities of the image are: 2D, high resolution, black and white

Transmission Electron Microscope Advantages: Highest magnification and high resolution the internal detail of cell can be seen Disadvantages: 2-D image black and white image the specimen must be dead; uses very thin slice of the specimen image is difficult to understand

Transmission Electron Microscope Scanning Electron Microscope Light Microscope Transmission Electron Microscope TEM Microscope

SEM Images Bed Bug

SEM Images House Fly

More SEM images Various blood cells Image of a spider’s leg

More SEM images Moth

6. Objective lenses magnify 4x, 10x and 40x Ocular lens magnifies 10X 2. Body tube 4. Revolving nose piece 3. Arm 6. Objective lenses magnify 4x, 10x and 40x 5. Stage clip 7. Adjustment knob 8. Slide 9. Stage 10. Coarse adjustment knob (low power) 11. Iris Diaphragm 12. Light 13. Fine adjustment knob 15. Base 14. Power switch

Microscope parts and functions Part Name Purpose of Part 1 Look through this to see an object under the microscope. Usually 10X magnification. 2 Connects the ocular to the microscope. 3 Connects the base and the barrel. 4 Turns to change the objective lenses to use. 5 Holds the slide in place 6 Used to view objects at three different magnifications 7 Moves the stage side-to-side, or forward and back to get the object into the field of view Ocular lens Body Tube Arm Nose piece Stage Clip Objective lens Stage adjustment knob

Microscope parts and functions Part Name Purpose of Part 8 Piece of glass onto which the object to be viewed is placed 9 Holds the slide for viewing 10 Raises and lowers the stage for focusing under low power 11 Adjusts the amount of light entering the field of view 12 Source of light 13 Slightly moves the stage to sharpen the image 14 Turns the illumination on or off 15 Supports the microscope Slide Stage Coarse focus Iris diaphragm Lamp Fine Focus Power Switch Base

How To Use a Microscope Make sure the objective lens with the lowest power is in place. Place the slide on the stage and secure the slide using the stage clip. Use the coarse focus knob to bring the objective lens close to the slide. Use the fine focus knob to focus. To move to high power, rotate the nosepiece to the high power objective lens. Use the fine adjustment knob to bring the image into focus.