Eukaryotic Cells and Parasites
o Protists o Fungi o Helminths o Arthropods
o Protists
o Fungi
o Helminths
o Arthropods
Terminology explanation: Prokaryote and Eukaryote
Pro = before Eu = true Karyon (Greek) = kernel or nucleus Nucleus. Membrane-bound compartment within an eukaryotic cell containing the genetic material (chromosomes) o Prokaryotic cell lacks a nucleus and evolved before the eukaryotic cell o Eukaryotic cell may have evolved from a large prokaryote after the latter surrounded its DNA with a membrane and then formed an internal symbiotic association with smaller prokaryotic cells that became mitochondria and chloroplasts in eukaryotic cells
Pro = before
Eu = true
Karyon (Greek) = kernel or nucleus
Nucleus. Membrane-bound compartment within an eukaryotic cell containing the genetic material (chromosomes)
o Prokaryotic cell lacks a nucleus and evolved before the eukaryotic cell
o Eukaryotic cell may have evolved from a large prokaryote after the latter surrounded its DNA with a membrane and then formed an internal symbiotic association with smaller prokaryotic cells that became mitochondria and chloroplasts in eukaryotic cells
Eukaryotic cells are larger and more complex than prokaryotic cells
1. Cell wall
Peptidoglycan never present (only in prokaryotes) Algae have cellulose (polysaccharide) Fungi and yeast have cellulose or chitin (polysaccharides) Protozoa do not have a cell wall
Peptidoglycan never present (only in prokaryotes)
Algae have cellulose (polysaccharide)
Fungi and yeast have cellulose or chitin (polysaccharides)
Protozoa do not have a cell wall
2. Cell membrane
Phospholipid bilayer Proteins Sterols (Prokaryotic cell membranes do not contain sterols, except the Mycoplasmas)
Phospholipid bilayer
Proteins
Sterols (Prokaryotic cell membranes do not contain sterols, except the Mycoplasmas)
3. Cytoplasm and internal structures -organelles and specialized compartments (not found in prokaryotes, except ribosomes)
Nucleus Contains chromosomes (DNA) surrounded by nuclear membrane Ribosomes Site of protein synthesis Larger than prokaryotic ribosomes Mitochondria Site of ATP synthesis Chloroplasts Site of photosynthesis in algae and other photosynthetic eukaryotes Cytoskeleton Network of protein fibers and tubes Support cell structure and are scaffolds for movement of various intracellular components (Ex. chromosomes during cell division) Membrane bound structures and compartments Endoplasmic reticulum Involved in synthesis of lipids and secreted proteins Golgi apparatus Packages proteins that the cell secretes into vesicles for export out of the cell Lysozomes and peroxisomes Compartments with chemicals and enzymes that digest proteins, lipids, food particles, bacteria, cell debris
Nucleus Contains chromosomes (DNA) surrounded by nuclear membrane
Ribosomes Site of protein synthesis
Larger than prokaryotic ribosomes
Mitochondria Site of ATP synthesis
Chloroplasts Site of photosynthesis in algae and other photosynthetic eukaryotes
Cytoskeleton Network of protein fibers and tubes
Support cell structure and are scaffolds for movement of various intracellular components (Ex. chromosomes during cell division)
Membrane bound structures and compartments
Endoplasmic reticulum
Involved in synthesis of lipids and secreted proteins
Golgi apparatus
Packages proteins that the cell secretes into vesicles for export out of the cell
Lysozomes and peroxisomes
Compartments with chemicals and enzymes that digest proteins, lipids, food particles, bacteria, cell debris
4. External structures
Flagella Larger, more complex than prokaryotic flagella Cilia Shorter and more numerous than flagella o Motility in protozoa o Movement of fluid across exterior surface of cell of multicellular organisms Ex. -Removal of mucus from the lungs -Transport of the egg toward the uterus in the oviduct
Flagella Larger, more complex than prokaryotic flagella
Cilia Shorter and more numerous than flagella
o Motility in protozoa o Movement of fluid across exterior surface of cell of multicellular organisms Ex. -Removal of mucus from the lungs -Transport of the egg toward the uterus in the oviduct
o Motility in protozoa
o Movement of fluid across exterior surface of cell of multicellular organisms
Ex.
-Removal of mucus from the lungs
-Transport of the egg toward the uterus in the oviduct
Principles of parasitology
I. Terms
Parasite --organism that lives at the expense of another living organism (host)
o Host --provides home and nutrients to parasite
Ectoparasites --live on surface of host
Ex. ticks, lice
Endoparasites --live within host
Ex. protozoa, fungi and worms
Vector --organism that transfers a parasite to new host
Ex. mosquito transfers malaria parasite
Reservoir --host that harbors a parasite that is transmitted to different hosts
Ex. Pigs are reservoirs for Trichinella A helminth (worm) that causes trichinosis in humans
Ex. Pigs are reservoirs for Trichinella
A helminth (worm) that causes trichinosis in humans
Endemic --organism or disease that is always present in a geographic location
Ex. Histoplasmosis. A fungal disease endemic to Ohio and Mississippi River alleys
Effects of parasites
1. Rob host of nutrients --may inhibit growth and development
2. Damage host tissue --intestines, liver, heart, brain, skin, clogged blood vessels
3. Trigger immune response by host --inflammation, fever
Important parasites and their diseases
A. Parasitic Protists (Protozoa)
1. Mastigophorans --have flagella
o Trypanosoma African sleeping sickness Transmitted by tsetse fly (reservoir for parasite and vector for transmission to host) o Leishmania Fever, fatigue, diarrhea, anemia Transmitted by sand flies o Giardia Backpacker's disease, diarrhea Transmitted by contaminated drinking water
o Trypanosoma
African sleeping sickness
Transmitted by tsetse fly (reservoir for parasite and vector for transmission to host)
o Leishmania
Fever, fatigue, diarrhea, anemia
Transmitted by sand flies
o Giardia
Backpacker's disease, diarrhea Transmitted by contaminated drinking water
Backpacker's disease, diarrhea
Transmitted by contaminated drinking water
2. Sarcodines --amoeboid, indefinite shape
o Entamoeba Amoebic dysentery: inflammation of intestines, bloody stools Transmitted by contaminated food and water
o Entamoeba
Amoebic dysentery: inflammation of intestines, bloody stools
Transmitted by contaminated food and water
3. Apicomplexans --not motile, complex life cycles
o Plasmodium Malaria: kills 1.5 to 3 million/year Transmitted to humans by mosquitoes
o Plasmodium
Malaria: kills 1.5 to 3 million/year
Transmitted to humans by mosquitoes
o Toxoplasma Toxoplasmosis Transmitted by contact with feces of cats & wild animals, a teratogen (can harm a developing fetus in the womb)
o Toxoplasma
Toxoplasmosis
Transmitted by contact with feces of cats & wild animals, a teratogen (can harm a developing fetus in the womb)
B. Fungi (molds and yeasts)
Molds have multicellular filaments called hyphae Yeasts are single-celled fungi Mycoses are infections caused by fungi
Molds have multicellular filaments called hyphae
Yeasts are single-celled fungi
Mycoses are infections caused by fungi
Some diseases caused by parasitic fungi
Plants: wilts, blights, rusts, smuts Humans and animals Trichophyton --athlete's foot and ringworm Histoplasma --histoplasmosis, respiratory infection Candida --vaginal and oral yeast infections
Plants: wilts, blights, rusts, smuts
Humans and animals
Trichophyton --athlete's foot and ringworm Histoplasma --histoplasmosis, respiratory infection Candida --vaginal and oral yeast infections
Trichophyton --athlete's foot and ringworm Histoplasma --histoplasmosis, respiratory infection
Candida --vaginal and oral yeast infections
C. Parasitic helminths (worms)
1. Flatworms
Flukes Liver, lungs and blood parasites Complex life cycle involves snails or mollusks as reservoirs
Flukes
Liver, lungs and blood parasites
Complex life cycle involves snails or mollusks as reservoirs
Tapeworms Intestinal parasites Human infection from eating contaminated meat
Tapeworms
Intestinal parasites
Human infection from eating contaminated meat
2. Roundworms
Trichinella --causes trichinellosis, acquired by eating undercooked pork Forms cysts in muscle tissue Heartworms --transmitted to dogs by mosquitoes Hookworms --intestinal parasites
Trichinella --causes trichinellosis, acquired by eating undercooked pork
Forms cysts in muscle tissue
Heartworms --transmitted to dogs by mosquitoes
Hookworms --intestinal parasites
D. Arthropod (insect) parasites
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SIUC / College of Science / Microbiology / Microbiology 201 http://www.micro.siu.edu/micr201/chapter5N.html Last updated: Feb. 8, 2006 /jh