Prokaryotic Cell Structure Flashcards
what are prokaryotic cells
cells with the simplest cell structures, being the first organisms to evolve on earth
what are the two domains of prokaryotic cells
bacteria or eubacteria (true bacteria and archaebacteria or archaea - in extreme environments)
what size are prokaryotic cells
0.1µm to 5.0µm
common structures to most prokaryotes
70S ribosomes
DNA in a loop
Cytoplasm
Plasma membrane
Cell wall
cytoplasm function
not divided into compartments, does not have membrane-bound organelles
site of many cellular reactions - metabolism
where 70S ribosomes are found
contains mainly cytosol (water based solution containing ions, small molecules and macromolecules)
plasma membrane function
responsible for regulating what materials move into and out of the cell as well as cell to cell communication
barrier separating the interior from its surroundings
a bilayer formed from phospholipids as a consequence of their hydrophobic and hydrophilic regions
archaea have a monolayer membrane
ribosome function
binds and reads mRNA during translation to produce proteins, 70S ribosomes (smaller)
composed of two subunits
cell wall function
provides shape and allows cell to withstand turgor pressure without bursting
contains murein/peptidoglycan (glycoproteins)
classifies some bacteria depending on how they react
pili function
only in some cells
enable the cell to attach to surfaces, swap DNA with other cells (conjugation)and may be used to harpoon DNA in the environment (assist with movement)
avoid attack by wbcs
capsule function
only in some cells
keeps the cell from dehydrating, from being attacked and helps adhere to surfaces
flagellum function
only in some cells
long extensions used in locomotion
rotate
can have more than one
DNA function
no nucleus but have genetic material, in a naked single circular DNA molecule (not associated with proteins) in the nucleoid and in smaller loops called plasmids
used across all forms of life
nucleoid function
contains DNA that is not enclosed in a membrane in a single loop and is naked
plasmid function
only in some cells
small loops of DNA separate from the nucleoid
contain genes that can be passed between prokaryotes (like antibiotic resistance)
circular and naked
replicated independently of the nucleoid DNA
can be shared between bacteria
how do they show up on light micrographs
arranged in groups or chains
small, typically <5µm
often gram-stained
can be helical, spherical or rod shaped
