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Classification of Eukaryotes (Fungi (Types (microscopic (yeast (Candia…
Classification of Eukaryotes
Structure
Boundary of cell
Cell wall
present in some fungi
rigid and provide strutural support and shape
different in chemical composition from prokaryotic cell walls
thick layer of polysaccaride fibers, composed of chitin
thin outer layer of mixed glycans
doesn't present in protozoa and helminths
Cytoplasmic membrane
bilayer of phospholipids with protein molecules embedded
contain sterole
gives stability, espercially important in cells without a cell wall
gram stains : pink
Internal
Cytoplasm
Organelles
Golgi apparatus
proteins modified and sent to their final destinations
do not form a continuous network
closely associated with ER in location and functiom
Mitochondria
energy generators
smooth, continuous outer membrane
inner folder membrane (folds are cristae)
cristae hold enzymes and electron carriers of aerobic respiration
matrix-consist of ribosomes, DNA, and enzymes
similar to a bacterium
have their own circular strand if DNA
use their SNA to produce proteins and enzymes required for their function
contain prokaryotic -sized 70s ribosomes
divide independently of the cell
Endoplasmic reticulum
used in transport and storage
micoscopic series of tunnels
two kinds
rough endoplasmic reticulum (RER)
protein syethsized on the ribosome, shunted into the cavity of the RER and held for later packing and transport
Smooth endoplasmic reticulum (SER)
No ribosomes
Nutrient processsing
Synthesis and storge of nonprotein macromolecules
Choroplasts
Vesicles
Lysosomes
contain enzymes in intracellular digestion of food particles and protection against invading microorganisms
participate in the removal of cell decris and damaged tissues
Vacuoles
membrane bound sacs containing fluids or solid particles to be digeted, excreted or stored
formed in phargocytic cells in response to food and other substances that have been engulfed
Nucleus: the control center
Nucleolus: site for RNA synthesis
Nuclear encelope: seperate nucleus from cytoplasm
Chromosomes
Bouns to histone proteins
visible during mitosis
long, linear DNA molecules
Ribosomes
distruibuted throughout the call
cytoplasm, cytoskeleton, RER, mitochondria and chloroplasts
site of protein synthesis
size and structure
Eukaryotic ribosome is 80S
seperats into 60S and 40 S subunits when translation terminates
reunite when a new initiation complex is formed
Cytoskeleton
Microtubules
Intermeduate filaments
Actin filaments
External
Glycocalyx
capsules
Slimes
function
protection
adherence of cells to surface
reception of signals from other cells and the environment
Appendages for locomotion
Cilia
shorter and more numerous
Flagella
smaller and simple
mde up of flagellin
movement rotatory
protein drive
Fungi
Types
decomposers
food spoilage
macroscopic
mushrooms
saprophytic
live on decaying and dead tissues
microscopic
mold
grow in the form of multicullar filaments called hyphae
Aseptate hyphae
form a long cell with mant nuclei
continuous cytoplam facilitates quick nutrient movement throughtout the filament
filament dies if hypha is ruptured beacuse cytoplasm leak
Septate hyphae
structure
the septa have openings called pores
pores allow the flow of cytoplasm and nutrients throughout the mycelium
have dividers called septa between cells
septa provides increased structural stability for the hyphae
septate hyphae completely colse the septa if they ae injured, preserving filament integrity
yeast
single round to oval cell that reproduce sexually and asexually
Candia albicans
thrush vaginal infectiov
pathogen of genital tract mostly in immunocompromised including AIDS patient
fungi mperfecti-fungi with no known sexual stage of reproduction
Saccaromyces cerevisiae
wine- fermentation capacity, low pH and high ETOH tolerance
beer- ferments sugar to alcohol even when oxygen is present
bread- produces carbi dioxide from sugar very rapidly
cell walls are rich in mannan and glucan
Cryptococcis neoformans
cause a fungal meningitis or skin lesions, often in immunocompromised patients such as AIDS patient
Hyphae are long threadkike cells found in the bodies of filamentous fungi or molds, can form pseudhypae
Dimorphic fungi
exist in two form- yeast or mold
depending on
thermally dimorphic- change due to temperature
at room temperature (25'C) grow as a mold
a body temperature (37'C) - grow as a yeast
environmental, physiological conditions, or genrtic characteristics of the fungus
Asexual spores
produce of mototic division of a single cell
Sporangiospores
formed by successive cleavages within the sproangium
sporangium sttached to the sporangiophore
released when the sporangium ruptures
Conidiospores
free spores
develop either by pinching off the tip of fertile hyphae or by segmentation of a vegetative hyphae
Sexual spores
fussion of two parental nuclei followed by meiosis
the result of fusion of fertile hyphae of two different strains
the union of differentiated male and female structures that produce fruiting structures for the dissemination of sexual spores (complex)
increase genetic variation
majority of fungi produce sexual spores at some point
Characteristics
unicellular and multicellular with sexual and asexual reprodutive lifesyles
aerobic to facultative anaerobic
Cell wall made of Chitin and grow best in sugar rich and acidic medium
Mycoses (infections)
Cutaneous
have affinity for the keratin of the skin, nails and hair
Subcutaneous
involve the deeper layers of skin and often muscle tissues, affect connective tissues below the dermis
Superificial
confined to the outermost layers of the skin and hair
Systemic
affect deep organs and blood and often create symptoms that resemble other diesase
opportunistic: part of normal microbiota with low virulence but affects immuocompromised host
trult pathogenic: cause disease in healthy human host when the inoculum is of sufficient concentration
Histoplamosis
causes by histoplama capsulatum
pulmonary lesions ans calcifications
Mycotoxicosis
eating food contaminated with fungal toxins
aflatoxin produced by Aspergillus flavus is associated with liver diesase
Allergies
Food poisoning
benifits of fungi
Production of
antibotics
alcohol
organic acids
viatmins
decomposing orgaic matter and returning essential minerals to the soil
food flavorings
Protists
Types
Protazoa
types
Amoeba
Mostly uninucleate and usually encyst in unpleasant conditions
Move using pseudopodia
Ingest food by surrounding and engulfing food (endocytosis), creating a food vacuole
Asexual reproduction by binary fission
Can cause amebic dysentery in humans – diarrhea and stomach upset from drinking contaminated water
examples
entamoeba
Naegleria
Acanthamoeba
Apicomplexans
Are obligatory intracellular parasites
Have special organelles located at the tips (apices) of the cells
organelles contain enzymes that punch through, slice open, and penetrate host tissues
Most are not motile except male gametes
Complex life cycles
Produce sporozoites following sexual reproduction
sporozoites are transmitted via the saliva of a feeding vector
Sporozoites infect cells
Cells infected with sporozoites eventually burst, releasing merozoites into the bloodstream
Entire group is parasitic
examples
Toxoplasma
Toxoplasmosis a disease of blood and lymphatics
Transmitted by Toxoplasma gondii - a spore-forming protozoan
Pregnant women are at risk of abortion; infants suffer from hydrocephaly - excessive accumulation of fluid in the brain
Cats are reservoirs
few have symptoms because the immune system usually keeps the parasite from causing illness
Plasmodium
Malarial Parasite
Transmitted by female Anopheles mosquito
Morphologic forms seen in erythrocytes are: ring forms, merozoites, and sporozoites
species
Plasmodium vivax
P. ovale
P. malariae
P. falciparum
Cryptosporidium
a zoonotic disease characterized by severe diarrhea with fluid and weight loss
Natural waterways in U.S. are contaminated by Cryptosporidium parvum oocysts due to livestock wastes
Indicator disease for clinical stage of AIDS
Neospora,
Flagelletes
used to direct food particles or cells into the organism’s mouth-like opening
Single nucleus
Parasitic forms tend to lack mitochondria and Golgi apparatus
Most form cysts
examples
Giardia lamblia
causes intestinal giardiasis
No mitochondria; multiple flagella
Trichomonas vaginalis
causes trichomoniasis – STD
Blood Flagellates
Arthropod borne parasites with complex life cycles
Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense cause African Sleeping Sickness
transmitted by the bite of an infected tsetse fly
Leishmania tropica causes Leishmaniasis Recidivans a.k.a Baghdad Boil or Aleppo Button
transmitted by the bite of an infected sand fly
two stages
Trophozoite stage
vegetative or feeding stage is frequently the cause of the pathology or symptoms
Cyst stage
dormant, resting, non-feeding, and resistant form that can withstand harsh environmental conditions
characteristic
Unicellular or colonial organism that lacks true tissues
chemoheterotrophs
found in soil, water and some reside in animal hosts
styles of locomotion
Some unusual species move by gliding or twisting
All protozoans but the Apicomplexa are motile by
Pseudopods (false feet)
Can serve as feeding structures
Flagella
Some attached along the length of the cell by the undulating membrane
From one to several
Undulatory movement
Cilia
Mostly distributed over the entire surface of the cell
Form characteristic patterns
two nuclei
macronucleus devoted solely to metabolism
micronucleus that controls reproduction
Reproduce asexually
covered in microscopic projections that look like tiny hairs
Are heterotrophs, feeding on bacteria and algae
examples
Balantidium coli
can cause diarrhea, weight loss and dysentery
Sweeping movement or pendular stroke
Identification and Cultivation
Presence of special organelles or cysts
Number of nuclei
Type, number, and distribution of locomotor structures
Identified clinically by Ova and Parasite Exam
Shape and size of cell
algae
Characteristic
mostly unicellular, but some are multicullar
can be heterotrophic or autotrophic
Helminthes
characteristics
Eukaryotic parasites including worms which live within a host.
Are multicellular but have unicellular egg or larval forms
types
Phylum: Platyhelminthes (flatworms)
Class: Cestoda (tapeworms)
Intestinal Flukes Fasciolopsis buski
Class: Trematoda (flukes)
Trematodes are the blood flukes that use humans as the definitive host
characteristic
Often segmented
Thin and flat
Phylum: Nematoda (roundworms)
Characterics
Elongate, Cylindrical
Live inside and feed off an animal's intestines
Unsegmented
Hookworm
Necator americanus
Ancylostoma duodenale
Infection is acquired by larval penetration of the host
Adult worms attach to intestinal mucosa and feed on blood of host causing anemia
Dracunculiasis
Guinea worm disease casued by Dracunculus medinensis
Contracted by drinking contaminated water
No animal or environmental reservoir
Infection must pass through humans each year
How to identify Helmomth infections
See helminth eggs in stool
High eosinophils in the blood