Download Understanding Cells Understanding Cells Prokaryotic Cells

2/17/2017
• They learned many things about cells.
Understanding Cells
– There are two major types of cells, prokaryotic cells
and eukaryotic cells.
• English scientist Robert Hooke
first identified cells over 300 years
ago while looking at cork under a
microscope he built.
– All cells have DNA, a cell membrane to protect
them, and are filled with a jelly-like substance called
cytoplasm.
• He saw honeycomb-like openings.
They reminded him of small
rooms, so he called them cells.
– Some cells have special structures that do specific
jobs, called organelles.
– Plant and animal cells have different structures
Understanding Cells
Prokaryotic Cells
• After Hooke’s discovery, other
scientists began to use better
microscopes to identify different
structures in the cells of plants and
animals.
• Over time, they developed cell theory.
Cell theory includes three principles.
• Prokaryotic Cells are very simple and
very abundant cells.
• They were the first cells to evolve.
• They are mostly bacteria.
• All have a hard cell wall.
Prokaryotic Cells
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• They do not store their DNA in a nucleus
(an area in the center that holds DNA)
• They do not have organelles (cell organs)
• They are unicellular.
• All have a hard cell wall on the outside for
protection.
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Prokaryotic Cells
• Some have flagella (whip-like tails used
for movement)
Understanding Cells (cont.)
How did scientists’
understanding of cells
develop?
Eukaryotic Cells
• Eukaryotic Cells are any cell that is not a
bacteria.
• They are more complex that prokaryotic
cells.
• They can be unicellular or multicellular.
Eukaryotic Cells
• They store their DNA in a nucleus (an area
in the center that holds DNA)
• They have organelles (cell organs)
• All have a hard cell wall on the outside for
protection.
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