Transcript Are eukaryotes that depend on another host for their nutrients

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Are eukaryotes that depend on another host
for their nutrients and metabolic activities.
Divided to
1-Protozoa: Unicellular.
2-Helminths: Multicellular.
3-Arthropods: Multicellular.
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Common stages of life cycle
1- Trophozoite: active growing stage
2- Cyst: resting non active stage
Can infect all major tissues and organs of the
body
Transmission of protozoan parasites by
1- injection via bites of blood sucking
insects
2- ingestion of infective stages
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Protozoa move by :
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Psuedopod: (extending part of protoplasm
towards direction of movement)
Example: Entamoeba species
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Flagella :
Example: Trypanosoma species, Giardia Lamblia
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Cilia:
Example: Balantidium coli
non motile:
Example : Plasmodium species
Trophozoite
Cyst
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Multicellular organisms with organ systems
as digestive, nervous , excretory system.
Have complicated life cycle
Mostly have different stages of life cycle
which are: ova(egg), larvae (Adult)
Adult worms can measure centimeters or
even meters long
Extracellular parasites
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Are classified according to shape into:
1- Nematodes (round worms) cylindrical thin
Example: Ascaris lumbricoides
2- Cestodes ( tape worms)flat long worms
Example: Tenia saginata,tenia solium
3- Trematodes( Flukes)leaf like flat worms
Example: Schistosoma species
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Are insects such as bugs ,fleas, biting flies,
mosquitoes etc.
Harmful effects of parasites
Discomfort, transmission of diseases(
malaria, yellow fever, typhus), cause
disease(amoebic dysentery, bilharzias),
damage to crops.
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Heterotrophic eukaryotes
Saprophytes: obtain nutrients from dead
organic material
Nucleated achlorophyllous organisms
Reproduce sexually and asexually
Surrounded by true cell wall
2 groups Yeast and mold
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Grow within a wide range pH(acidic-alkaline)
Grow at room temperature (can grow at cold
temp)
Prefer moist or humid atmospheres
Can be cultured in Sabouraud Dextrose agar
media (SDA) or potato dextrose agar (PDA)
that contains a source of protein (peptone)
and a source of carbohydrate (dextrose)
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The commonest microscopic examination of
fungi is LACTO-PHENOL- COTTON BLUE tease
mount or reagent (LPCB)
Benefits of fungi: important in baking ,
pharmaceutical(antibiotic),brewing industries.
Also as saprophytes and as food.
Harmful effects: cause a lot of diseases in
skin, hair, nail and systemic diseases.
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Yeast
Unicellular, round or oval( tear drop)shape
Multiply asexually by budding resulting in
production of 2 cells
Molds
Multicellular branching hyphea forming a
mycelium.
Fungi
Molds using LPCB x40
Alternaria
species
Fungi
Molds using LPCB x40
Penicillium
Fungi
Molds using LPCB x40
Aspergillus species
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Iron needles
made from iron because fungi dig into agar
thus it is difficult to culture them with wire
loop
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Virus in Latin means poison
All viruses are obligate intracellular parasites(
can multiply only in living cells)
Possess a single type of nucleic acid either
DNA or RNA (Ss or Ds)
Nucleic material is enclosed in a protein coat
called capsid. ( both capsid and nucleic acid
are called nucleocapsid)
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Vary in size from 20-300nm
Cannot be seen by bright field microscope
Can be examined by Electron microscope
Can infect humans, animals, plants and
bacteria
Viruses that infect bacteria are called
bacteriophages
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Isolation of viruses :
a- animal inoculation
b- embrynoted egg inoculation
c- cell culture
Cytopathic effects
are morphological changes in cell lines due
to virus infection.