1. Section 7.2 – Cells and Technology
Chapter 7

2. Light Microscopes Earliest microscopes were simple microscopes
Used only one lens
Used light to view objects

3. Zacharias Janssen designed a microscope that used two lenses to produce a large image
Created the first compound light microscope

4. Electron Microscopes http://www.youtube.co m/watch?v=fToTFjwUc5 M
Used to see objects that are too small to be seen with a light microscope
Specimens are illuminated with a beam of electrons instead of a beam of light

5. Electron micrograph – photograph of an image from an electron microscope
Extremely powerful – magnifying images up to 1.2 million times ME

6. Transmission electron microscope (TEM)
Type of electron microscope
Produces a two-dimensional image magnified X to X

7. Scanning electron microscope (SEM)
Creates a three-dimensional image
Can be used to view the shapes of specimens in realistic detail
Can reach a magnification of X
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8. Confocal Laser Scanning Microscope (CLSM)
Makes it possible to study specimens that are too thick to be viewed using a compound light microscope
Don’t need to cut the specimen
Creates a series of two-dimensional images

9. Scanning Tunnelling Microscope (STM)
Allows scientists to obtain an image of atoms on an object’s surface
More magnifying power than an electron microscope
Researchers are able to produce images of molecules such as DNA

10. A Molecular World genes direct the activities of our cells
genes are sections of DNA (deoxyribonucleic acid)
DNA is found in a cell’s nucleus

11. DNA has a sugar-phosphate backbone
DNA has four bases that make up its ‘rungs’:
adenine (A), cytosine (C), guanine (G), thymine (T)
adenine always pairs with thymine
cytosine pairs with guanine

12. Gene sequencing – mapping the order of all of a gene’s bases
Human Genome Project
International project to sequence all to human genes
Will help diagnose and treat genetic disorders
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13. Stem Cells are blank cells that can develop into any type of cell
other cells in your body can only divide to make other cells like them
stems cells are found in embryos, umbilical cords and bone marrow
scientists hope to use stem cells’ to grow tissues or organs for transplants

14. Living or Not?
virus’ are not considered living organisms; they are classified as non-living
a virus contains genetic material that is enclosed in a protein coat
needs to take over a host cell to be able to reproduce
i.e. HIV