Ch 12: Eukaryotes

Question 1

Most molds are ____ while most yeasts are ____.

Answer 1

• Aerobic
• Facultative anaerobes

Question 2

True or false. Most fungi can tolerate lower pHs and higher osmotic pressures than bacteria?

Answer 2

True

Question 3

What are Mycorrhizae?

Answer 3

Symbiotic fungi with plants that aid in nutrient absorption

Question 4

Multicellular fungi are identified based on _____

Answer 4

Physical appearance; including colony characteristics and reproductive spores

Question 5

A hyphal mass is referred to as a

Answer 5

Mycelium

Question 6

True or false. Yeasts are multicellular fungi.

Answer 6

False. They are unicellular

Question 7

What are the two methods of division in yeasts?

Answer 7

1. Fision
2. Budding

Question 8

Does Saccharomyces cerevisiae reproduce by budding or by fission?

Answer 8

Budding

Question 9

Buds that fail to detach from the parent cell form structures known as ____

Answer 9

Pseudohypha

Question 10

What yeast requires formation of pseudohypha to aid in its pathogenicity?

Answer 10

Candida albicans

Question 11

One yeast cell in its lifetime can produce about ____ daughter cells by budding

Answer 11

24

Question 12

What is the Crabtree effect?

Answer 12

Describes the phenomenon whereby S. cerevisiae produces EtOH aerobically in the presence of high external glucose concentrations

Question 13

Yeast can use oxygen or an organic compound as a final electron acceptor. Which method do they prefer?

Answer 13

• Oxygen
• Aerobic respiration

Question 14

What are dimorphic fungi?

Answer 14

Fungi that grow either as a mold, forming hyphae, or as a yeast through budding

Question 15

Dimorphism in fungi can be triggered by? (2)

Answer 15

1. Temperature (37 C for yeast-like; 25 C for mold-like)
2. CO₂ levels

Question 16

What is the difference between asexual and sexual spores?

Answer 16

• Asexual: genetically identical to parent; originate from a single hypha
• Sexual: arise from the fusion of nuclei from two opposite mating strains

Question 17

What is a telomorph?

Answer 17

Fungus that reproduces both sexually and asexually

Question 18

What is an anamorph?

Answer 18

Fungi that reproduce only asexually

Question 19

What is a conidiospore/conidium?

Answer 19

• Asexual spore not enclosed in a sac
• Produced in a chain at the end of a conidiophore
• Easily dispersed (dust)

Question 20

What is a sporangiospore?

Answer 20

• Asexual spore formed within a sac (sporangium) at the end of an aerial hypha
• One sporangium contains hundreds of sporangiospores

Question 21

What are arthroconidia?

Answer 21

• Condia subtype
• Spores relased by fragmentation

Question 22

What are blastoconidia?

Answer 22

• Conidia subtype
• Budding from a parent cell

Question 23

What are chlamydoconidia?

Answer 23

• Conidia subtype
• Thick-walled spores formed by rouding and enlargement within hyphae

Question 24

What are the three phases of reproduction for sexual spores?

Answer 24

1. Plasmogamy: union of two haploid cells with mixing
2. Karyogamy: + and - nuclei fuse
3. Meiosis: diploid nucleus produces haploid nuclei as sexual spores, which may be genetic recombinants

Question 25

What phyla are considered the “4 true fungi"

Answer 25

1. Zygomycota 2. Ascomycota 3. Basidiomycota 4. Chytridiomycota

Question 26

What is a zygospore?

Answer 26

* Large diploid spore (sexual) enclosed in a thick wall * Multi-ncleated diploid reproductive stage resulting from the fusion of haploid nuclei from two cells

Question 27

What is an ascospore?

Answer 27

* Sexual spore produced in a saclike structured (ascus) * Results from the fusion of nuclei from two cells * Haploid spores are produced during meiosis

Question 28

What is a basidiospore?

Answer 28

* Sexual haploid spore * formed externally on a pedestal (basidium)

Question 29

Any fungal disease is called a \_\_\_\_

Answer 29

Mycosis

Question 30

What type of mycosis is limited to hair shafts and surface epidermal cells; also prevalent in tropical climates?

Answer 30

Superficial

Question 31

What type of mycosis infects only the nails, epidermis, and hair; with transmission occurring by direct contact?

Answer 31

Cutaneous or Dermatomycoses

Question 32

What type of mycosis is found beneath the skin caused by fungi that live in soli or vegetation; infections occur by direct spore implantation into puncture wound?

Answer 32

Subcutaneous

Question 33

What type of mycosis can affect a number of organs and tissues; transmitted by inhalation of spores?

Answer 33

Systemic

Question 34

What type of mycosis is usually harmless but can become pathogenic in a compromised host (i.e. immunocompromised)

Answer 34

Opportunistic

Question 35

**Identify the phylum:** * Call conjugation fungi, sporangium fungi, or common mold * Molds that have coenocytic hyphae * Produce sporangiospores asexually * Produce zygospores sexually

Answer 35

Zygomycota

Question 36

**Identify the phylum:** * Sac fungi * Includes moldes with septate hyphae and some yeasts * Asexual spores: conidiospores * Sexual spores: ascospore

Answer 36

Ascomycota

Question 37

**Identify the phylum:** * Club fungi * Includes fungi that produce mushrooms * Septate hyphae * Asexual spore: conidiospores (or fragmentation) * Sexual spore: basidiospore

Answer 37

Basidiomycota

Question 38

True or false. *Penicillium* is an anamorph.

Answer 38

True