Questions and Answers
What is the characteristic of the genetic material in prokaryotes?
What is the function of plasmid DNA in bacteria?
Which of the following organelles are found in prokaryotic cells?
What is the size of typical bacteria?
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Which of the following is NOT a characteristic of prokaryotic cells?
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What is the function of the cytoplasm in prokaryotic cells?
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Which of the following bacteria is an exception to having a cell wall?
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What is the significance of plasmid DNA in higher classes?
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What is the approximate length of Mycoplasmas, the smallest cells?
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What is a unique feature of prokaryotes?
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What is the typical shape of the bacterium Coccus?
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What is the outermost layer of the cell envelope in prokaryotes?
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What is the general size range of bacteria?
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What is the main function of the cell wall in prokaryotes?
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Which of the following is a characteristic of the plasma membrane in prokaryotes?
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Which of the following is a characteristic of prokaryotic cells?
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What is the name of the smallest isolated single cell?
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What is the term for the process of staining cells to distinguish between Gram-positive and Gram-negative bacteria?
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Which of the following is an example of a prokaryotic cell?
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What is the function of glycocalyx in prokaryotes?
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What is the shape of the bacterium Vibrio?
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What is the term for the infoldings of cell membrane in prokaryotes?
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Which of the following is a characteristic of Gram-positive bacteria?
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What is the fundamental organization of prokaryotic cells?
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Study Notes
Cell Size and Shape
- Mycoplasmas, the smallest cells, are only 0.3 µm in length.
- Bacteria can be 3 to 5 µm in length.
- The largest isolated single cell is the egg of an ostrich.
- Red blood cells are about 7.0 µm in diameter.
- Cells vary greatly in shape, including disc-like, polygonal, columnar, cuboid, thread-like, or irregular shapes.
Prokaryotic Cells
- Prokaryotic cells include bacteria, blue-green algae, mycoplasma, and PPLO.
- They are generally smaller and multiply more rapidly than eukaryotic cells.
- Prokaryotes exhibit a wide variety of shapes and functions.
- They have a cell wall surrounding the cell membrane, except in mycoplasma.
- The fluid matrix filling the cell is the cytoplasm.
- There is no well-defined nucleus in prokaryotes.
- Genetic material is basically naked, not enveloped by a nuclear membrane.
- Prokaryotes have plasmids, which are small circular DNA outside the genomic DNA, conferring unique phenotypic characters to bacteria.
Cell Envelope and Modifications
- The cell envelope consists of a tightly bound three-layered structure: glycocalyx, cell wall, and plasma membrane.
- Each layer of the envelope performs distinct functions, but they act together as a single protective unit.
- Bacteria can be classified into two groups based on the differences in the cell envelopes and the manner in which they respond to the staining procedure developed by Gram.
- Gram-positive bacteria take up the gram stain, while Gram-negative bacteria do not.
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Description
This quiz covers the basic structure and types of cells, including red blood cells, white blood cells, and epithelial cells.