BIOL 1002 Chapter : Chapter 22 Notes

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15 Mar 2019

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The diversity of fungi: key features of fungi. Pores in the septa allow cytoplasm to stream from one cell to the next. Fungal decomposers (saprobes) feed on dead organic material and. Fungal parasites absorb nutrients from cells of living hosts and may. Some symbiotic fungi live in mutually beneficial relationships with wastes cause disease (athlete"s foot) other organisms. Fungal predators consume living organisms: fungi reproduce by means of spores, spores are haploid reproductive cells capable of developing into an adult fungus. Asexual spore formation: spores germinate and develop into a new mycelium by mitosis, results in the rapid production of genetically identical clones, sexual reproduction, typically occurs under conditions of environmental change or stress. Two different hyphae fused so that the nuclei share a common cell. The different haploid nuclei fuse to form a diploid zygote. Zygote undergoes meiosis to form haploid sexual spores.

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1.A mycologist visits your biology class and discusses herresearch on a particular fungus that lives on the bark of damagedspruce trees. She explains that the fungal hyphae of her researchorganism is heterokaryotic. You raise your hand and request thatshe define that word. Her correct response is

heterokaryotic means that thenuclei of the fungal hyphae are genetically the same.

heterokaryotic means that eachcompartment of the hyphae contain two distinct nuclei.

heterokaryotic means that thenuclei of each compartment of the hyphae are geneticallydistinct.

heterokaryotic means that each compartment of the hyphaecontains only one nucleus.

2. Select the true statements concerning reproduction ofbasidiomycetes. (Check all that apply.)

The adult forms of a typicalbasidiomycete consists of a mass of dikaryotic primarymycelia.

The secondary mycelia fuse to formprimary mycelia. The primary mycelia form the fruiting body.

The gills of an Amanitamushroom contains basidiospores.

Karyogamy produces a diploid zygotethat undergoes meiosis.

Meiosis produces basidiospores, and the fusion of spores fromdifferent mating strains produces the primary mycelium.

3. In the life cycle of a zygomycete, after the zygospore isformed, the next event will be

karyogamy.

4. Why does champagne have bubbles?

CO₂ is used to makeglucose during respiration.

Yeast fermentation continues afterthe champagne is bottled.

Dead yeast cells releaseCO₂ into the bottles.

Yeast produce O₂ during aerobic respiration.

5. Many antibacterial antibiotics interfere with proteinsynthesis. Why would these not be a good target for antifungaldrugs?

Fungi can rapidly metabolizedrugs.

Fungi produce few proteins.

Chitin cell walls prevent uptake ofdrugs.

Human and fungal ribosomes areextremely similar to each other.

Fungi absorb proteins during decomposition of organicmatter.

6. Which molecule would be an indicator of fungal contaminationin a drug preparation?

Deoxyribose

7. Why can lichens live on bare rock?

UV radiation powers enzymes thatallow the fungus to extract organic material from itssurroundings.

The fungi are autotrophic.

The photosynthetic endosymbiontprovides the fungus with nutrition.

They absorb heat from the sun.

They secrete acids to liberate minerals from the bare rock.

8. What type of symbiotic relationship is exemplified bymycorrhizal fungi?

Parasitism

Commensalism

Atavism

Mutualism

9. In what way are bacteria and fungi similar?

Cell wall components

Ribosome structure

Design of the nucleus

Ecological function

10. he fungal group that is most closely related to ancestralfungi are the

Zygomycota.

Basidomycota.

Ascomycota.

Chytridomycota.

11.Select the INCORRECT statement(s) concerning reproduction ofthe mold Rhizopus.

Fungal hyphae are multinucleate andhaploid.

Meiosis comes immediately beforefertilization.

The germinating zygosporangiumcontains diploid nuclei.

Rhizopus exclusivelyreproduces asexually.

Zygospores are only produced after meiosis.

12. Primary mycelia contain twice as much DNA as secondarymycelia.

True

False

13.After severe floods homeowners often return home to find thewall of their homes covered in mold. How does mold survive on wetwallboard?

It eats the gypsum that makes upthe wallboard.

Spores from within the wallboardgerminate and start growing.

It uses the wallboard as asubstrate but extracts nutrients from the air.

It digests the cellulose in the paper backing.

14. Why is the term "fungal cell mitosis" not technicallyaccurate?

The septa between nuclei form priorto mitosis.

All of the mycelium undergoesmitosis at the same time.

All stages of mitosis occur withinthe nucleus.

The mitotic spindle spans across the perforations of thesepta.

15. Select the true statements regarding the lifecycles ofbasidiomycetes and ascomycetes. (Check all that apply.)

Basidiocarps and ascocarps arefunctionally equivalent.

Dikaryotic mycelia are the same asdiploid mycelia.

Ascogenic hyphae are functionallyequivalent to secondary mycelia.

Both basidiospores and ascospores are stored externally.

16. A division of fungi that lacks septa in their hyphae exceptwhen they form sporangia or gametangia is the

	ascomycetes.
	zygomycetes.
	chytridomycetes
	basidiomycetes. PLEASE HELP

ceruleanzebra964

Fungi Fungi are the great decomposers of the biosphere. Most plants form mycorrhizae with fungi to increase absorptive area without having to grow more roots, in this relationship fungi recieve carbohydrates from plants. Humans consume fungi, mushrooms, may use fungi as a source of drugs for blood pressure, antibiotics and immunosuppresive drugs. Fungi are used in biotechnology to produce fermetation products, and some have been very useful models to study gentics in eukaryotic cells that are unicellular such as yeasts. About one third of fungi may cause infections, mycoses, in plants, animals and humans. Fungi tolerate concentration of salt and sugar that plasmolyze bacteria in perserved foods exposed to air which contains fungal spores may germinate and may spoil food. Fungi have two body shapes, molds and yeasts. Mold are large and made of long filamentous hyphae. Hyphae form mats called mycelium ( plural is mycelia). Mycelia may extend for miles underground, making fungi the largest organism on earth. The visible portion of subterrean fungi are the fruitng bodies such as mushrooms. Yeasts are globular and unicellular. They may bud forming up 24 daughter cells from a single cell. When budding is incomplete it may produce a psuedohypa. Fungi that may exist in both body types are dimorphic fungi. In general, the yeast form of a dimorphic fungus is a pathogen, the filamentous form is not pathogenic. Examples are Histoplasmosis capsulatum (histoplasmosis) and Coccidiodes immitis (coccidioidomycosis). Fungi are saprobes, they absorb nutrients from the remains of dead plants or they lasso nematodes. Fungi may derive nutrients from a living plant utilizing haustoria which are modified hyphae that penetrate living plant tissue. Some fungi use melanin to absorb gamma rays which they convert to chemical energy. Some herbivores have fungi in thier gut microbiome to help digest plants. Zygomycota contains 1100 species and reproduces asexually through sporangiaspores, which form in a sac called a sporangium on a stalk called a sporangiaphore. An example is Nosema which is an obligate intracellular parasite in insects and honeybees. Ascomycota havd 32,000 species form haploid ascospores in sacs called ascus (asci plura) and reproduce asexually with condiospores which develop on the tips of hyphae on stalks called conidiophores. Examples are Claviceps purpurea, ergot, which grows on grain and causes abortions in cattle and hallucinations in humans. Penicillium the source of the first antibiotic discovered by Fleming in the 1940s. Saccharomyces, a facultative anaerobe, ferments sugar to produce alcohol and carbon dioxide gas and is used in baking and brewing. Neurospora was used as a model to study molecular biology, Beadle and Tatum established one gene one enzyme using this model organism.

14. Why are there more antibacterial drugs than antifungal drugs? Basidiomycota have fruiting bodies called basidiocarps. Basidiospores are dispersed by the wind and germinate in warm moist environments. An example is the pathogen Cryptococcus neoformans the leading cause of fungal meningitis

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BIOL 1002 Chapter : Chapter 22 Notes

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