The Eukaryotes: Fungi, Algae, Protozoa and Helminths Flashcards
List the defining characteristics of fungi.
They have hyphae
They also have mycelium
Molds are mostly filamentous
Yeasts are non filamentous, unicellular fungi; budding yeasts divide asymmetrically.
Fungi can be dimorphic
Contain reproductive fungal spores
They like environments which are hostile to bacteria
They can metabolize complex carbohydrates such as lignin in wood.
Hyphae
each of the branching filaments that make up the mycelium of a fungus.
Mycelium
Mass of hyphae.
Fungi are dimorphic, what does this mean?
fungi can grow as ether mold or yeast depending on the temperature; yeasts like 37 degrees celsius and molds like 25 degrees celsius.
How do fungal spores differ from bacterial spores?
fungal spores are formed from aerial hyphae, they are not as resistant as bacterial spores, they are true reproductive spores.
Fungi like to grow in environments not suitable to bacteria, what are some of these environmental factors?
they like low pH (acidity)
they prefer low moisture
They like high osmotic pressure (lots of salt or sugar)
What are two beneficial and two harmful aspects of fungi?
Fungi can be used to kill pests such as termites, they can also be used to make bread, beer, and HBV vaccine. Fungi can be harmful because they can cause food spoilage (mold) or disease
List the defining characteristics of protozoa.
Unicellular, eukaryotic chemoheterotrophs. Large and diverse group. Few are pathogenic.
Found in soil and water and as normal microbiota in animals.
Trophozoite: Vegetative form (feeding and growing).
Asexual reproduction via fission, budding, or schizogony (multiple fission).
Sexual reproduction via conjugation.
Some protozoa can produce a cyst that provides protection during adverse environmental conditions.
Differentiate an intermediate host from a definitive host.
A definitive host is a host in which a parasite reaches sexual maturity (adult stage) . An intermediate host is a host in which a parasite passes one or more of its asexual stages (larval stage), usually designated first and second if there is more than one
List the distinguishing characteristics of the two classes of parasitic helminths, and give an example of each
a
Provide a rationale for the elaborate life cycles of parasitic worms
a
Define arthropod vector
arthropods that carry pathogens that cause disease
Differentiate between a tick and a mosquito, and name a disease transmitted by each.
A tick is part of the class arachnida and has 8 legs in its adult form, it cannot fly. A mosquito is part of the class insecta and has 6 legs, mosquitos can fly. An example of a tick borne disease would be lyme disease, and an example of a mosquito borne disease would be malaria.
List the causative agent, mode of transmission, and clinical symptoms of scabies
- caused by Sarcoptes scabiei
- transmitted by direct skin to skin contact with the infected or indirect contact with fomites such as linens or clothing.
- symptoms include intense itching and pimple-like skin rash
chemoheterotrophic fungi
has to ingest carbon for energy and nutrition; does this by absorption, it recycles nutrients and returns them to the soil.
What are the oxygen requirements of mold?
they are aerobic
What are the oxygen requirements of yeasts?
They are facultatively anaerobic
Mycology
The study of fungi
Most fungi are ____________, few are __________ of plants and animals.
decomposers
parasites
the number of serious fungal infections is _______________.
on the rise
Not all fungi make ___________.
mushrooms
cells in hyphae release __________ so fungus can absorb nutrients and make _________.
enzymes
ATP
The mushroom is the _____________ body of a fungus and produces _________ which are released from its ________, the remaining __________ is under ground
reproductive
spores
gills
mycelium
How is yeast used in HBV vaccine?
it is used as an adjuvent or additive to the vaccine to help increase the body’s immune response.
Mycoses
fungal diseases
Systemic mycosis
infection deep within body, affects many tissues and organs. Histoplasmosis and coccidiomycosis.
Subcutaneous mycosis
Caused by saprophytic fungi, e.g.: Sporotrichosis.
Cutaneous mycosis/ Dermatomycosis
affects keratin-containing tissues (hair, nails, skin).
Superficial mycosis
localized on hair shafts and superficial skin cells.
Fungus alone has only a minimal capacity to damage skin directly. Superficial mycoses affect approximately 9 million Americans and account for 5% of skin diseases. These fungi invade only the dead or keratinized layers of the skin, hair and nails.
Opportunistic mycoses
caused by normal microbiota or fungi that are not usually pathogenic (E.g.: Candidiasis and Pneumocystis pneumonia)
usually systemic
Algae
Mostly photoautotrophs (photosynthetic), mostly in ocean; two kinds, diatoms and dinoflagellates
Diatoms
- Unicellular, store energy in form of oil
- Domoic acid causes Neurological disease
- Ingestion of mussels that fed on diatoms can cause intoxication (also affects birds and sealions)
Dinoflagellates (plankton)
- Some produce neurotoxins: red tide
- Kills fish, marine mammals, and humans, e.g.: parasitic shellfish poisoning (PSP)
Medically Important Protozoa
Arcaezoa
Microspora
Amoebozoa
Apicomplexa
Euglenozoa
Euglenozoa
Hemoflagellates- any parasitic flagellate protozoan that lives in the bloodstream.
- move by flagella
Trypanosoma
Apicomplexa
- not mobile
- intracellular
Plasmodium, Babesia, Toxoplasma, Cryptosporidium
Amoebozoa
- Cause Amoebiasis
(move via pseudopodia or pseudopods) Entamoeba histolytic (dysentery; secretes enzymes that breakdown tissue) and Acanthamoeba (eye infection)
Microspora
(no mitochondria and no microtubules) – diarrhea and keratoconjunctivitis in AIDS patients