Fungi

Question 1

Most fungi are _____.

Answer 1

Most fungi are multicellular.

Question 2

Is yeast, a type of fungi, multicellular?

Answer 2

No, yeast is unicellular.

Question 3

Fungi cell walls contain _____.

Answer 3

Fungi cell walls contain chitin.

Question 4

How would fungi be classified based on how they obtain nutrients?

Answer 4

Fungi would be classified as chemoheterotrophs.

Question 5

How do fungi acquire nutrients? Describe this process.

Answer 5

Fungi acquire nutrients by absorption, by secreting hydrolytic enzymes and acids to break down complex organic molecules into simpler ones that can be absorbed.

Question 6

Describe the structure of mushroom fungi.

Answer 6

Mushroom fungi are comprised of tiny filaments called hyphae which are interwoven to form a mat. Hyphae can be divided by walls called septa (making it a septate fungus). Pores in the septa allow for the movement of organelles.

Question 7

What is mycelium?

Answer 7

Mycelium is the underground portion of hyphae that has a large surface area for absorption (the main body of the fungus).

Question 8

What is the fruiting body?

Answer 8

The temporary fruiting body is the above ground portion of the hyphae and is only for reproduction (it produces spores).

Question 9

What is coenocytic fungi?

Answer 9

Coenocytic fungi don’t have septa, making them one continuous cell.

Question 10

What are the three types of fungi (relevant to this course)? Which of the two are symbionts?

Answer 10

Saprotrophs, parasitic and mutualistic. Parasitic and mutualistic fungi are symbionts.

Question 11

Describe saprotrophs.

Answer 11

Saprotrophic fungi live on and obtain nutrients from dead/decomposing organic matter (they break-down this organic matter by secreting enzymes). They are important decomposers in the ecosystem.

Question 12

Describe parasitic fungi.

Answer 12

Parasitic fungi have modified hyphae called haustoria, which can penetrate host tissue for absorption of nutrients. The host is alive and is harmed by the fungi. Some mutualistic fungi also have haustoria.

Question 13

What is lichen?

Answer 13

Lichen is a mutualistic relationship between a photosynthetic organism and fungus.

Question 14

Describe mutualistic fungi.

Answer 14

Mutualistic fungi make up the fungi portion of lichen.

Question 15

How many types of lichen are there? Describe them.

Answer 15

1. Algae and fungus: algae is photosynthetic and fungi provides substrate (surface for an organism to live on; provides structure).
2. Cyanobacteria and fungus: cyanobacteria is photosynthetic and can fix nitrogen. In this case, the supporting fungi also receives usable nitrogen from this relationship.

Question 16

Describe mycorrhizae.

Answer 16

Mycorrhizal fungi attach to the roots of plants. The hyphae create networks in the soil that increase the plant’s access to nutrients and moisture in the soil. The fungi absorbs organic nutrients from the plant, making this a mutualistic relationship.

Question 17

Describe the life cycle of fungi (asexual preproduction).

Answer 17

Mycelium (n) will produce a spore forming structure that will bud off of the main body. The spores this structure produces will spread out and will germinate into new mycelium (if the conditions for growth as present).

Question 18

Describe the life cycle of fungi (sexual preproduction).

Answer 18

Two different mycelia of opposing mating types find each other and perform plasmogamy (they fuse their cytoplasms, but their nuclei will not fuse). Following the heterokaryotic stage, which can last years, the nuclei will fuse (karyogamy). This fusion results in a diploid zygote, eventually transforming into a spore forming structure. Spores form from meiosis. These spores eventually germinate to form new mycelium.

Question 19

Generally, fungi reproduce by releasing _____ which are dispersed by wind and water.

Answer 19

Generally, fungi reproduce by releasing spores which are dispersed by wind and water.

Question 20

Spores are usually _____ and are produced by either _____ or _____.

Answer 20

Spores are usually haploid and are produced by either mitosis or meiosis.

Question 21

In _____ conditions, spores are produced asexually (by _____).

Answer 21

In favourable conditions, spores are produced asexually (by mitosis).

Question 22

In _____ conditions, spores are produced sexually (by _____).

Answer 22

In unfavorable conditions, spores are produced sexually (by meiosis).

Question 23

Why do fungi reproduce sexually in unfavorable environmental conditions?

Answer 23

Fungi in unfavorable conditions are not well adapted to their environments. They reproduce sexually with the objective of increasing genetic variability so that the offspring may gain alleles that will allow them to be better adapted to the environment.

Question 24

Fungi can also reproduce through _____ of hyphae.

Answer 24

Fungi can also reproduce through fragmentation of hyphae (asexual).

Question 25

Yeast is a _____ fungi that does not form _____.

Answer 25

Yeast is a unicellular fungi that does not form hyphae.

Question 26

How do yeast reproduce?

Answer 26

Yeast reproduce through budding. Offspring cells bud off the parent cell.

Question 27

Yeast carry out _____. The equation for this chemical reaction is _____ –> _____.

Answer 27

Yeast carry out fermentation:

Sugar –> ethanol + CO2 + ATP

Question 28

Describe the role of fungi in the ecosystem.

Answer 28

Fungi are detritivores (decomposers) that convert organic molecules (from dead organic matter) into inorganic molecules that can be recycled back to primary producers. Some fungi (parasitic fungi) act as consumers. Though they are not primary producers themselves, mutualistic fungi can help primary producers.

Question 29

Many fungi can produce _____, which we then use to kill _____.

Answer 29

Many fungi can produce antibiotics, which we then use to kill bacteria.

Question 30

One way fungi compete is through _____ _____.

Answer 30

One way fungi compete is through chemical warfare. They produce antibiotics to kill bacteria around them, so that they can obtain once contested nutrients.