1)All living organisms are composed of cells.They may be unicellular or multicellular.2)The cell is the basis 'unit' of life.3)Cells are formed from pre-existing cells during cell division.4)Energy flow occurs within cells.
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What different types of telescopes?
1)Transmission Electron Microscopes. 3) Scanning Electron Microscopes
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How does a Transmission Electron Microscope work?
Transmission electron microscopes use an electron beam that passes through the sample and is reflected on a fluorescent screen. Therefore, the sample has to be very thin.
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How does a Scanning Electron Microscope work?
When using a scanning electron microscope the sample doesn’t need to be as thin as the electrons don’t pass through the sample, but instead they strike the surface. This causes the build up of a 3d structure.
A bacterium is a single-celled organism. A bacterial cell has a different structure to an animal or plant cell. It has cytoplasm, a membrane and a surrounding cell wall, but the genetic material in a bacterial cell is not in a distinct nucleus.
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What is a yeast cell?
Yeast is a single-celled organism. Like bacterial cells, yeast cells have cytoplasm and a membrane surrounded by a cell wall. But unlike bacterial cells, yeast cells have a nucleus.
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Why is bacteria not seen as a cell?
Using electron microscopes we now know that bacteria have a cell wall. This is similar to a plant cell wall but is more flexible. Bacteria do not have a nucleus. They do have two types of DNA – plasmid and chromosomal.
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Other cards in this set
Card 2
Front
What different types of telescopes?
Back
1)Transmission Electron Microscopes. 3) Scanning Electron Microscopes
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