Download A prokaryotic cell

Prokaryotic cell :-
A prokaryotic cell is a cell that does not have a true nucleus. The
nuclear structure is called a nucleoid. The nucleoid contains most of
the cell’s genetic materials this cell represented by the bacteria
and the cytobacteria . it is bounded by a plasma membrane but
has no other separate membrane –bound organelles .
Prokaryotic cell do not posses mitochondria , or photosynthetic
chloroplasts. Most prokaryotic posses a cell wall external to the
cytoplasmic membrane which contains muramic acid , a compound
not found in eukaryotic cells.
prokaryotic Posses ribosome smaller than those found in the
cytoplasm of eukaryotic cells . prokaryotic are unable to take
any material unless it is first made soluble .Bacteria have no
nucleus but all the chemical elements of nucleic acid and protein
synthesis are present . Although their nutritional requirements vary
greatly ,most bacteria are free living if given appropriate energy
source .They divide by binary fission and can be grow in artificial
culture .
The diversity of living organisms is incredible. It is estimated that
at least 5 million different kinds of plants, animals, microorganism
exist . this teeming diversity is divided into five kingdom :
1- Kingdom monera: they are simplest in structure , their cell of
prokaryotic type , they have no membrane bound compartment
within them . they are unicellular microorganism such us bacteria,
blue-green algae.
2- kingdom protista : they are multicellular organisms or
unicellular microorganisms but all are of eukaryotic type such us
protozoa and alga
3-kingdom fungi : having the true fungi .
4- kingdom plante : having the true plant .
5- kingdom animalia : having the true animals .
Prokaryotic cell
Eukaryotic cell
1-it is simple ,primitive.
1- It is more complicated modern.
2-lack of membrane enclosed
nucleus & membrane -bounded
organelles.
2- have nucleus & other type of organelles.
Endoplasmic reticulum
Golgi complex
Lysomes
Mitochondria
3-reproduce by simple binary
Chloroplasts
fission.
3- Reproduce by mitosis & meiosis.
4- Ribosomes: 70S
4- Ribosomes: 80S
5-e.g : bacteria & blue- green algae.
5- e.g: fungus, plant ,animal.
Phyllum : Protozoa
Included unicellar , many exist in groups called colonies . Each cell
usually represent an in dependent unit. Some are spherical to
oval, some are elongated, & some even change their shape as
they move along a surface. Some may be as small as (10 µm) in
length & some may measure (200µm) certain species may
measure(1-2µm). Typical protozoa are holozoic they ingest their
food as solid particles through a mouth opening or cytosome
after ingestion the food is contained in a food vacuole. Enzymes
are secreted in to vacuole.
Once dissolved they enter the cytoplasm. Any food not digested in
the vacuole extracted through an anal pore or brought to the
surface.
All protozoa are able to reproduce both asexually & sexually.
Asexually most by splitting into two cells of equal size. However
unlike bacteria which divide by simple transverse fission (cross
wise) most protozoa divide longitudinally (length wise) unequal
fission or budding also is found. Sexual reproduction by
conjugation.
1- Class: Mastigophora : flagellated ,elongated cell which is
surrounded by a pellicle, may have mouth opening & a gullet .
major pathogens are :
Trypanosome , Leishmania , Trichomonas, Giardia .
Leishmania spp.
2- Class: Sarcodina : flexible amoeba , may form cysts , major
pathogen is Entamoeba histolytica ( cause the amoebic dysentery
).
Entamoeba histolytica trophozoite
• 3-Class: Sporozoa : all are non motile , animal parasites with a
complex life cycle that may require different hosts for sexual &
asexual reproduction don’t engulf particulate matter. Major
pathogens are: Plasmodium spp (malaria ), Toxoplasma gondii
(toxoplasmosis ).
Toxoplasma gondii tissue cyst
Plasmodium spp.
4- Class: Ciliata: Highly developed cells covered with short, hair
like projection called cilia , shaped of cells highly variable , but
constant within species Paramecium (free living ciliate ) Balantidium
coli (dysentery).
Balantidium coli •