Chapter 31

Question 1

Fungi have an extremely high surface-to-volume ratio. What is the advantage of this characteristic to an organism that gets most of its nutrition through absorption?
A) The high ratio allows for more material to be acquired from the surroundings and transported through the cell membrane.
B) The lower volume prevents the cells from drying out too quickly, which can interfere with absorption.
C) This high ratio creates more room inside the cells for additional organelles involved in absorption.
D) This high ratio means that fungi have a thick, fleshy structure that allows the fungi to store more of the food it absorbs.

Answer 1

A) The high ratio allows for more material to be acquired from the surroundings and transported

Question 2

What are the filamentous mats formed by most fungi called?
A) mycelia
B) hyphae
C) haustoria
D) arbuscles

Answer 2

A) mycelia

Question 3

A fungal spore germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of the following accounts for the outward growth of the mycelium?
A) karyogamy
B) mycelial flagella
C) breezes distributing spores
D) cytoplasmic streaming in hyphae

Answer 3

D) cytoplasmic streaming in hyphae

Question 4

Which of the following best explains how mycorrhizal fungi are more efficient than plants at acquiring mineral nutrition from the soil?
A) Hyphae are 100 to 1,000 times larger than plant roots.
B) Hyphae have a smaller surface area-to-volume ratio than do the hairs on a plant root.
C) Mycelia are able to grow in the direction of food.
D) Fungi secrete extracellular enzymes that can break down large molecules.

Answer 4

D) Fungi secrete extracellular enzymes that can break down large molecules.

Question 5

Plasmogamy can directly result in which of the following types of cells?
A) cells with a single haploid nucleus or dikaryotic cells
B) heterokaryotic cells or dikaryotic cells
C) heterokaryotic cells or cells with two diploid nuclei
D) dikaryotic cells or cells with two diploid nuclei

Answer 5

B) heterokaryotic cells or dikaryotic cells

Question 6

It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi’s use. What is the best evidence in support of this hypothesis?
A) Fungi survive better when they are associated with plants.
B) Radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated.
C) Fungi associated with plants have the ability to undergo photosynthesis and produce their own sugars, while those not associated with plants do not produce their own sugars.
D) Radioactive labeling experiments show that plants pass crucial raw materials to the fungus for manufacturing sugars.

Answer 6

B) Radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated.

Question 7

7. Which of the following structures in an ascomycete is haploid?
   A) ascospore
   B) ascocarp
   C) ascus
   D) basidium

Answer 7

A) ascospore

Question 8

Diploid nuclei of the ascomycete Neurospora crassa contain 14 chromosomes. A single diploid cell in an ascus will undergo one round of meiosis, followed in each of the daughter cells by one round of mitosis, producing a total of eight ascospores. How many chromosomes would a single ascospore nucleus of this species contain?
A) 7 chromosomes
B) 14 chromosomes
C) 21 chromosomes
D) 28 chromosomes

Answer 8

A) 7 chromosomes

Question 9

Which of the following types of fungi often live in the digestive tracts of sheep and cattle?
A) ascomycetes
B) mucuromycetes
C) chytrids
D) basidiomycetes

Answer 9

C) chytrids

Question 10

Which of the following best describes the physical relationship of the partners involved in lichens?
A) Fungal cells are enclosed within algal cells.
B) Lichen cells are enclosed within fungal cells.
C) Photosynthetic cells are surrounded by fungal hyphae.
D) Fungi grow on rocks and trees and are covered by algae.

Answer 10

C) Photosynthetic cells are surrounded by fungal hyphae.

Question 11

Which of the following statements describes an adaptive advantage associated with the filamentous nature of fungal mycelia?

Answer 11

an extensive surface area well suited for invasive growth and absorptive nutrition

Question 12

Which of the following best explains how mycorrhizal fungi are more efficient than plants at acquiring mineral nutrition from the soil?

Answer 12

Fungi secrete extracellular enzymes that can break down large molecules.

Question 13

Plasmogamy can directly result in which of the following types of cells?

Answer 13

heterokaryotic cells or dikaryotic cells

Question 14

Which of the following structures carries out sexual reproduction in ascomycetes?

Answer 14

ascocarps

Question 15

A fungal spore germinates, giving rise to a mycelium that grows outward into the soil surrounding the site where the spore originally landed. Which of the following accounts for the outward growth of the mycelium?

Answer 15

cytoplasmic streaming in hyphae

Question 16

At which stage of a basidiomycete’s life cycle would reproduction be halted if an enzyme that prevented the fusion of hyphae was introduced?

Answer 16

plasmogamy

Question 17

Some fungal species live in plants and can kill herbivores that feed on the plant. What type of relationship does this fungus have with its host?

Answer 17

Mutualistic

Question 18

Researchers grew two plants of different species (plant 1 and plant 2) and added the same mychorrhizal species to the soil. They then measured the growth of each plant after one month. Plant 1 grew significantly more than plant 2. Which of the following conclusions is most consistent with these results?

Answer 18

plant 1 formed a mutualistic relationship with the mycorrhizal fungi and plant 2 did not