october 27, 20151 unit 1: cellular biology 1.1 cell theory & the microscope
TRANSCRIPT
April 20, 2023 1
UNIT 1: CELLULAR BIOLOGYUNIT 1: CELLULAR BIOLOGY
1.1 Cell Theory & the Microscope1.1 Cell Theory & the Microscope
Cell Theory
1. All living things are composed of one or more cells.
2. Cells are the basic structural and functional units of life.
3. All cells arise from the division of other cells
Note: Robert Hooke discovered cells in 1655
How? …………
Robert Hooke
Hooke viewed a thin cutting of cork and discovered empty spaces contained by walls which he termed them cells
Compound Light Microscope
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Compound Light Microscope1. ocular
2. body tube
3. arm
4. stage clip adjustment knob
5. coarse adjustment knob
6. fine adjustment knob
7. revolving nosepiece
8. objective
9. aperture
10. stage clip
11. stage
12. condenser
13. diaphragm
14. light
15. base
Compound Light Microscope
Microscope Part
Function
1. ocular eyepiece lens, magnifies 10X
2. body tube directs light into ocular, supports
3. arm support
4. stage clip adjustment knob
moves slide around
5. coarse adjustment knob
moves stage up and down to focus image
Compound Light Microscope
Microscope Part
Function
6. fine adjustment knob
fine focus for most clear image
7. revolving nosepiece
holds objective lenses & facilitates changing
magnification
8. objective lens further magnifies the image
9. aperture opening to allow light to hit the specimen
10. stage clip holds slide in place
Compound Light Microscope
Microscope Part
Function
11. stage place specimen on it
12. condenser focuses light into a beam
13. diaphragm controls the amount of light hitting the specimen
14. light sends out light rays so specimen is visible
15. base supports microscope
Compound Light Microscope• has two lenses
1. ocular lens (10X)2. objective lens (4X, 10X, 40X)
- Low 4X- Medium 10X- High 40X
magnification:
the ability of lenses to enlarge the image of a specimen
magnification = ocular lens X objective lens400X = 10X times 40X
Other kinds of Microscopes
• Do you know any other kinds?
• ..\Videos\Different-Kinds-of-Microscopes[www.savevid.com].3gp
The Transmission Electron Microscope (TEM):
• How it works:Uses invisible beam of electrons that
pass through the specimen.
Best to observe:
Very thin pieces of the specimen.
Magnify up to:5 000 000X
Human Lung Tissue – Alveolar area
The Scanning Electron Microscope (SEM):
http://legacy.mos.org/sln/sem/seminfo.html
How it works: Reflects electrons from the surface of the
specimen.
Magnifies to:
300 000X
Best to observe:
Thicker specimens, surface features
Radiolarian (SEM)
• single-celled organism.• live in large quantities as part of the
ocean's plankton.
Magnification: X 750
Bladderwort
• Plant that live in fresh water• Lives where nutrients are scarce• Supplements its diet with insects or
other small organisms
Magnification: X 100
• http://www.telegraph.co.uk/science/picture-galleries/7924099/Creepy-crawlies-Amazing-Scanning-Electron-Microscope-pictures-of-insects-and-spiders.html
TEM & SEM
Scanning electron microscope image of a snowflake.
Transmission electron microscope image of the influenza virus.
Cholera TEM OR SEM??
Microscope ActivityWorking in pairs, identify all of the parts of the microscope. (Quiz each other)
Materials: compound light microscopeslide & cover slip coloured picture from a magazine
1. Cut out a small letter “e” and picture from the magazine.
Answer the following questions with your partner:
a) What happens when you move the slide to the right?
b) What happens when you move the slide down?
c) Describe the magnified image when looked at under high power? How does this differ when viewed with the unaided eye?