Catégories : Tous - genetic - cytoplasm - bacteria - prokaryotic

par NURUL NADIA BINTI NARONI / UPM Il y a 8 années

400

Prokaryotic Cells

Prokaryotic cells are characterized by their lack of membrane-bound organelles and a nucleus. Their genetic material, comprising DNA and RNA, is found in the cytoplasm, often in circular forms and small pieces called plasmids.

Prokaryotic Cells

Prokaryotic Cells

main structure

genetic material
contain large quantities of genetic material in the form of DNA and RNA
contain small pieces of DNA called plasmids
ribosome
build proteins by translating messages sent from DNA
smaller and have a slightly different shape and composition
cytoplasm
does not contain organelles
gel-like, fluid substance
plasma membrane
responsible for controlling what gets into and out of the cell
can have multiple plasma membrane

cell before nucleus, divide into two

bacteria
bacteria shape

streptococci

sarcinae

tetrads

diplococci

coccus

various form (singly, in pairs, chains or clusters)
various shape (round, flattened, thick, thin, short or long)
genetic material not enclosed in a nuclear membrane
unicellular organisms
archea
found in extreme environment
membrane fats are ether
cell wall lack peptidoglycan
three main group: - methanogens -extreme halophiles -extreme thermophiles

features

small ribosome 70s
no membrane bound organelles
reproduction by binary fission
complex cell wall
circular DNA
smaller size
unbound nucleoid
2-20 micrometer