MODULE 2 : prokaryotic cell structure Flashcards
what is a prokaryotic cell?
prokaryotic cells are less complex than eukaryotic cells and they don’t have a true nucleus
e.g. bacterial cells, blue - green algal cells
how many domains are there and what are there?
3 domains : eukaryotes, archaea and bacteria
bacteria
small unicellular organisms measuring between 1 -10 micrometres across
they have different shape and single cells can join together to form chains
plasma membrane
made of a phospholipid bilayer
controls what enters and exits the cell
chemical reactions take place there
cell wall
gives shape and rigidity to the cell
made of two polysaccharides:
- glycoprotein called peptidoglycan
- glycolipid called teichoic acid
mesosome
a tightly folded region of the plasma membrane which folds out into the cell
contains all the membrane bound proteins required for respiration and cell division
folding gives it a large surface are
nucleoid
found free in the cytoplasm not membrane bound
made of double stranded DNA but not associated with any proteins
sometimes referred to as bacterial chromosome
70s ribosomes
smaller than eukaryotes which are 80s
free in the cytoplasm not membrane bound
used for protein synthesis
cytoplasm
mainly made up of water and contains highly organised system of proteins
area where most chemical reactions take place
flagellum
a rotating helical shaped tail used for movement
made of protein called flagellin
some bacteria have or many flagella
capsule
a thick sticky material secreted on the outside of the cell wall
aids cell adhesion to surfaces/cells
protection against desiccation (drying out) and engulfing by white blood cells
plasmids
small circles of DNA, separate from the main DNA loop
used to exchange DNA between bacterial cells
useful for genetic engineering
genes for antibiotic resistance often occur here
