prokaryotic cells and viruses (cell structure (cytoplasm (contains…
prokaryotic cells and viruses
contains ribosomes - but they are smaller than those in a eukaryotic cell.
it is mainly made of lipid and proteins. it controls the movement of substances into and out of the cell.
it supports the cell and prevents it from changing shape. its made of a polymer called murein. Murein is a glycoprotein.
some prokaryotic cells also have a capsule made up of secreted slime. it helps to protect the bacteria from attack by cells of the immune system.
they are small loops DNA that aren't part of the main circular DNA molecule. plasmids contain genes for things like antibiotic resistance, and can be passed between prokaryotes. plasmids are not always present in prokaryotic cells. some prokaryotic cells have several.
they don't have a nucleus. instead the DNA floats free in the cytoplasm. its circular DNA, present as one long coiled strand. its not attached to any histone proteins.
it is a long hair-like structure that rotates to make the rotates to make the prokaryotic cell move. Not all prokaryotes have a flagellum. some have more than one.
the cells replicate by a process called binary fission.
step one: the circular DNA and plasmids replicate. the main DNA loop is only replicated once, but plasmids can be replicated loads of times.
step two: the cell gets bigger and the DNA loops move to opposite poles of the cell.
step three: the cytoplasm begins to divide (and new cell walls begin to form)
step four: the cytoplasm divides and two daughter cells are produced. each daughter cell has one copy of the circular DNA, but can have a variable number of copies of the plasmids.