Fungi Flashcards
(95 cards)
0
Q
What cells are fungi?
A
Eukaryotic cells so contain similar features to human cells
1
Q
What useful materials do fungi produce?
A
Food, chemicals and pharmaceuticals
2
Q
What do antifungal agents give rise to?
A
Toxic effects
3
Q
What do most antifungal agents target on the fungi?
A
Fungal membrane
4
Q
A characteristic of fungi is metabolism what is this?
A
Energy obtained from chemical reactions (rather than from photosynthesis)
5
Q
Fungi have a heterotrophic mode of nutrition, what is this?
A
Absorb simple molecules from external environment
6
Q
Are fungi motile?
A
Generally not
7
Q
What is the cell wall of a fungi like?
A
Rigid
8
Q
Are fungi unicellular or multicellular?
A
Some are unicellular and some are multicellular
9
Q
What does the cell wall of fungi contain?
A
Chitin - polymer of acetylglucosamine + cellulose and polymers of glucose (glucans)
10
Q
What type of fungi are yeast?
A
Microscopic - Unicellular
11
Q
What type of fungi are molds/mushrooms?
A
Macroscopic multicellular
12
Q
What is hyphae?
A
Cells of fungi that are in branching filaments
13
Q
Do yeast grow as hyphae?
A
No because they are unicellular
14
Q
Do molds/mushrooms appear on hyphae?
A
Yes because they are multicellular
15
Q
What is mycelium?
A
A thick Mass of hyphae
16
Q
What phases does a fungi life cycle involve?
A
Growth phase and reproductive phase
17
Q
What are septa and what do they do?
A
Septa are cross walls they divide the cytoplasm into separate cells
18
Q
What are coenocytic?
A
Hyphae containing many nuclei
19
Q
Most fungi are saprobes, what is this?
A
Any organism esp. A fu his or bacterium that live and feeds on dead organic matter
20
Q
What do vegetative hyphae do?
A
Anchor the mold and used for absorbing nutrients
21
Q
What are aerial hyphae?
A
Reproductive structures of the fungus
22
Q
Where are spores formed?
A
At the tip of aerial hypha
23
Q
What do spores give?
A
Colour to the fungal mycelium
24
What are fungi that do not possess septa called?
Fungi that lack these divisions are termed nonseptate or coenocytic hyphae
25
What is the shape and the size of yeast cells?
Oval cells measuring 5-10 micrometers in diameter
26
How do yeast reproduce?
Sexually and asexually
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What can biphasic or dimorphic fungi form?
Can form a mycelium under particular environmental conditions and subsequently revert to a yeast form when exposed to other conditions
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Give an example of a biphasic or dimorphic fungi?
Candida albicans
29
How do fungi take up nutrients?
Through absorption
30
What temperature do most fungi grow best at?
Room temperature
31
Are fungi aerobic?
Yes
32
Where do psychrophilic fungi grow?
In the refrigerator
33
What pH do many fungi thrive at?
Slightly acidic pH (pH 5-6)
34
What is a spore?
A reproductive feature of a fungi which is a single cell
35
What are bacterial spores?
Resistance mechanism
36
What does a single spore have the capability to regenerate?
The entire mycelium of a fungus
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What are sporangia?
Sacs that asexual spores develop in
38
What happens in budding?
A blastospore develops from the parent cell
39
What do fragments of hyphae yield?
arthrospores
40
What is ergosterol?
A provitamins D2 a white crystalline organic solid belonging to the steroid family found only in fungi, and is chemically related to cholesterol
41
How is ergosterol converted to vitamin D2?
By ultraviolet irradiation
42
What is ergosterol produced by?
Yeast
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What is ergosterol used for?
As a vitamin D food supplement to alleviate tickets a deficiency disease of bond caused by lack of vitamin D in the diet
44
How many phyla can fungi be classified in?
5
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What are the chytridiomycota related to?
The oldest known fungi
46
What do chytridiomycota have?
They are primarily aquatic
| They have flagellated reproductive cells
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What are Glomermycota?
Groups of mycorrhizae that live in over 80% of plants' roots
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What do mitosporic fungi lack?
A sexual cycle of reproduction
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What are zygomycetes?
Terrestrial fungi that grow as mold on bread and produce
50
What do zygomycetes form during sexual reproduction?
They form a heterokaryotic, diploid zygospore
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What percentage of know fungi does asomycetes account for?
75%
52
Give examples of fungi that are ascomycetes.
```
Bakers yeast
The fungus that produce aflatoxin
The edible morel
The mold that produces penicillin
Candida albicans, the cause of thrush, diaper rash and vaginitis
```
53
By what reproduction does ascomycetes produce conidia?
Asexual reproduction
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By what reproduction does ascomycetes produce ascospores?
Sexual reproduction
55
What are lichens?
Mutualistic association between a fungus (frequently an ascomycete) and a photosynthetic organism
56
What are basidiomycetes?
Club fungi, incurring mushrooms and puffballs.
| Some form mycorrhizae and others are plant pathogens.
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What do basidia on the gills of mushrooms caps contain?
Sexually-produced basidiospores
58
What is saccharomyces?
A fungus that can ferment sugars
59
What is S.cerevisiae?
A model eukaryotic organism they are used in bread backing and alcohol production
60
What are fungal toxins called?
Mycotoxins which are poisonous or deadly when consumed
61
What do Aspergillus flavus and A.parasiticus produce?
Carcinogenic aflatoxins which contaminate many agriculture products
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What is ergotism (poisoning) caused by?
Claviceps purpurea which grow on grains
63
What can ergot in grains cause?
Numbness
Hot and cold sensations
Seizures
Paralysis of nerve endings
64
What is Lysergic acid diethylamide (LSD)?
A derivative of an alkaloid in ergot
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What does mushroom poisoning of mycetod million mimic? And what does it cause?
Mimics Acetylcholine affecting peripheral nervous system.
| Causes hallucinations and produces intoxication
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What percentage of deaths form mushroom ingestion does Amanita cause?
90%
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What symptoms does Amanita cause?
Produces cramping, vomiting and diarrhoea.
| In a week, leads to liver and kidney failure
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What is Dermatophtosis?
An infection of the body surface infections /ringworm a on the skin, hair or nails
69
What can Dermatophtosis be transmitted by?
Domestic animals
| Formites like floors,mats or towels
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What are symptoms of Dermatophtosis?
Blister-like lesions with a thin fluid discharge
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How can Dermatophtosis be treated?
Treatment involves changing the skin environment (moisture, pH, ect.)
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What is candidiasis?
A mild, superficial infection
73
When can Candida albicans cause candidiasis in a individual?
When the immune system is compromised
Or
When microbial populations in the body change
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What is Vulvovaginitis? And what are symptoms?
A yeast infection.
Itching, burning , reddening
Swelling, discharge
75
What may excessive antibiotics use cause?
Decrease of protective bacteria in the vagina and intestine, allowing C.albicans to flourish
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What does oral candidiasis (thrush) involve?
White curd-like growth in the mucous membrane of the mouth
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What does onychia involve?
Hardening, browsing , and distortion of fingernails
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What is sporotrichosis?
An occupational hazard that occurs in people who work with wood, wood products and soil
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What can infection with spores of sporotrichosis cause?
Pus-filled lesions
80
Which individuals does cryptococcosis occur in?
Immunocompromised individuals
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What is Cryptococcsis caused by? And where is it found?
Caused by Cryptococcus neoformans.
| Is found in urban soil and pigeon droppings.
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Where can inhaled C.neoformans be inhaled and where can it rarely infect?
```
Penetrate to the air sacs of lungs.
Cells can (rarely) pass into the bloodstream, infecting the brain and meninges
```
83
What can histoplasmosis produce? And what is it caused by?
A systemic disease.
| It is caused by Histoplasma capsulatum
84
Where is Histoplasma capsulatum found? And what are the symptoms?
If is found in dry,dusty,soil, chicken coops , and bat caves.
Usually mild influenza-like symptoms
85
Where is blastomycosis usually acquired? And what is it caused by?
Via the respiratory route.
| Caused by Blastomyces dermatitidis
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What can Blastomycosis cause?
Lung and skin infections.
Inhalation causes lung lesions, persistent cough, chest pains.
Chronic pneumonia and may disseminate to other organs in AIDS patients
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What is coccidioidomycosis? What cause it? And where can it be seen?
Potentially lethal infection.
Caused by coccidioides immitis.
Seen in desert valleys of the SW U.S
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What can inhalation / infection of coccidiomycosis cause?
A dry, hacking cough.
Chest pains
High fever
Rarely infection disseminates to tissues such as internal organs and meninges of the spinal cord
89
What can Pneumocystis pneumonia (PCP) cause and what is it caused by?
Lethal pneumonia
| Caused by Pneumocystis jiroveci, which has a complex life cycle in the alveoli.
90
What individuals is PCP common in? And how is it transmitted?
Common infection in AIDS patients. Transmitted through respiratory droplets
91
What other fungi cause mycoses?
In Aspergillosis, conidia enter the body and grow as a mycelium. It is caused by Aspergillus fumigates
92
What may need to be done to remove aspergilloma?
Surgery to remove it from the lungs
93
What is the cause of otomycosis in earwax?
Aspergillus
94
What can disseminated Aspergillus affect?
The heart
