Fungi Flashcards
Round to oval shape
• Uses asexual reproduction
Yeast cell
• Long, threadlike cells found in filamentous tungi or molds
• Pseudohypha: chain of yeast
Hyphae
• Some fungi can take either form dependent on growth conditions
Dimorphic
Used in winemaking, baking, and brewing since ancient times
• Isolated from skin of grapes
Saccharomyces cerevisiae
• Acquire nutrients from a wide variety of substrates
• All fungi are heterotrophic
Heterotrophic
Obtain substrates from dead plants and animals
Saprobes
• Live on the bodies of living animals or plants
Parasites
the woven, intertwining mass of hyphae that makes up the body or colony of a mold
Mycelium
cross walls dividing hyphae into segments
Septa
fungal reproductive bodies
Spores
Types of hyphae
Vegetative hyphae
Reproductive hyphae
Germination
Formed by successive cleavages within a sporangium
Sporangiospores:
Free spores not enclosed by a spore-bearing sac
Conidiospores or Conidia:
Purpose of sexual spore formation
• Important variations occur when fungi of different genetic makeup combine their genetic material
• Slight variations in the form and function are potentially advantageous to the adaptation and survival of the species
Identification in medical specimens
• Isolation on special media
• Observation microscopically and macroscopically
• Asexual spore-forming structures and spores used to identify genus and species
• Hyphal type, colony texture, pigmentation, physiological characteristics, and genetic makeup
Pathogenic fungis
• Community-acquired infections caused by environmental pathogens
• Hospital-associated infections caused by fungal pathogens in clinical settings
• Opportunistic infections caused by pathogens infecting already weakened individuals like transplant, cancer, and HIV-positive patients
Beneficial impacts of fungi
• Essential role in decomposing organic matter and returning essential minerals to the soil
• Form stable associations with plant roots that increase water and nutrient absorption
• Production of antibiotics, alcohol, organic acids, and vitamins
• Food flavoring
• Alcohol in beer and wine, gas that causes bread to rise
any eukaryotic unicellular or colonial organism that lacks true tissues
Protists
• Floating community of microscopic organisms
• Essential role in the aquatic food web
• Produce about 70% of the earth’s oxygen
• Primary medical threat from algae is through ingestion of toxins during a red tide (Paralytic shellfish Poisoning)
Plankton
Organelles can be highly specialized into structures analogous to
• Mouths
• Digestive systems
• Reproductive tracts
• Legs-means of locomotion
Nutritional habitat and range
• Heterotrophic and require their food in complex organic form
• Free-living species:
• Scavenge dead plant or animal debris
• Graze on live cells of bacteria and algae
• Parasitic species:
• Live on fluids of the host such as plasma and digestive juices
• May actively feed on tissues
• Amoeboid motion
• Serve as feeding structures
Pseudopods (false feet)
Vary in number from one to several
Flagella
Distributed over the entire surface of the cell in characteristic patterns
Cilia
• Motile feeding stage
• Requires ample food and moisture to remain active
Trophozoite
• Dormant, resting stage
• Formed when conditions become unfavorable for growth and feeding
• Important factor in the spread of disease
Cyst
• Simple, asexual methods, usually mitosis
• Several parasitic species reproduce by multiple fission
• Sexual reproduction also occurs
Protozoan reproduction:
form of genetic exchange between two cells
Conjugation
