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BIOL 227 Lecture Notes - Lecture 4: Arbuscular Mycorrhiza, Mycelium, Zygomycota

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3 May 2016

School

Concordia University

Department

Course

Professor

Donald Gray Stirling

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Document Summary

Fungi are heterotrophs: they cannot make their own food. A fungus absorbs nutrients from the environment outside of its body by secreting hydrolytic enzymes into their surroundings. Other fungi use enzymes to penetrate the walls of cells, enabling the fungi to absorb nutrients from the cells. Fungal hyphae form an interwoven mass called a mycelium that infiltrates the material on which the fungus feeds. The hyphae are divided into cells by cross walls, or septa. Septa generally have pores large enough to allow ribosomes, mitochondria and even nuclei to flow from cell to cell. Some fungi lack septa, known as coenocytic fungi, these organisms consist of a continuous cytoplasmic mass having hundreds or thousands of nuclei. Results from the repeated division of nuclei without cytokinesis. Some fungal species have specialized hyphae called haustoria, which the fungi use to extract nutrients from, or exchange nutrients with, their plant hosts.

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Related Questions

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

dikaryon formation.

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?

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

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.

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

1. Which of the following is NOT true of mycorrhizae?

A) This groupâs name means âfungus rootsâ

B) Plant roots provide mutualistic mycorrhizae with organic nutrients

C) Mycorrhizal fungi may form a mutualistic symbiosis with plants

D) Mycorrhizal fungi provide plants with organic nutrients absorbed from the soil

2. Which of the following terms is INCORRECTLY defined or identified?

A) saprobic fungi-eukaryotic heterotrophs which absorb their nutrients from living organisms

B) plasmogamy-the union of the cytoplasms of two parent mycelia

C) dikaryon-the stage in fungal sexual reproduction in which hyphae contain pairs of haploid nuclei of opposing mating types

D) zygosporangia-the environmentally resistant dikaryotic stage of the Zygomycota

3. In the Kingdom Fungi,

A) a mycelium is a body formed of a network of hyphae

B) a haploid multicellular form alternates with a diploid multicellular form

C) coenocytic hyphae have multiple cross-walls with large pores

D) cell walls are reinforced with proteins similar to collagen

4. Which of the following groups is INCORRECTLY matched with a structure for asexual reproduction?

A) Zygomycota-sporangium(sporangia)

B) Yeast-budding off of new yeast cells

C) Basidiomycota-basidium(basidia)

5. Select the TRUE statement about animal development:

A) Deuterostome development is indeterminate

B) Mesoderm in protostomes arises as outpocketings of the primitive gut

C) In deuterostomes, the blastopore ultimately becomes the mouth of the adult

D) Radial cleavage is characteristic of protostome development

E) All of the above are true