Chapter 1: Types of Cells
The major differences between Prokaryotic and Eukarotic cells are
that prokaryotes don't have a nucleus and rarely have membrane bound
organelles, (the only exception I have heard of is bacteria with
vacuoles). The both do have DNA for genetic material, have a exterior
membrane, have ribosomes, accomplish similar functions, and are very
diverse. For instance, there are over 200 types of cells in the human
body, that very greatly in size, shape, and function.
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- Prokaryotes are cells without a nucleus. They have genetic
materials but are not enclosed within a membrane. These include
bacteria and cyanophytes. The genetic material is a single circular DNA
and is contained in the cytoplasm, since there is no nucleus.
Recombination happens through transfers of plasmids (short circles of
DNA that pass from one bacterium to another). They do not engulf solids
nor do they have centrioles or asters. There are pictures of 2
prokaryotes below. Prokaryotes have a cell wall made up of
peptidoglycan.
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- These are cells with a nucleus, this is where the genetic
material is surrounded by a membrane much like the cells membrane.
Eucaryotic cells are found in humans and other multicellular organisms
(plants and animals) also algae, protazoa. They have both a cellular
membrane and a nuclear membrane, also the genetic material forms
multiple chromosomes, that is linear and complexed with proteins that
help it 'pack' and is involved in regulation.
Eukaryotes are composed of both plant and animal cells.
Plants vary from animal cells in that they have large vacuoles, cell
wall, chloroplasts, and a lack of lysosomes, centrioles, pseudopods,
and flagella or cilia. Animal cells do not have the chloroplasts, and
may or may not have cilia, pseudopods or flagella, depending on the
type of cell.
- Go to Chapter 2: 'Parts
of the Cell'
- WWW Cell Biology Course Index
- Go back to the Introduction.
Please send questions/comments/suggestions to: Mark
Dalton at markwdalton@gmail.com.
