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Review Biology 20 – Kingdom Fungi
Written Answers
1) Describe the reproduction of Basidomycetes (3).
Club fungi reproduce sexually by forming spores in a structure called a basidium which can be found lining gills inside the basidiocarp (the mushroom cap). Each gill is lined with thousands of
dikaryotic basidia. In each basidium, two nuclei fuse to forma a zygote. The zygote undergoes meiosis to form four haploid nuclei, that develop into four basidospores which are released into the air.
2) Compare an Ascocarp with a Basidiocarp – draw a picture to support your answer (4).
A basidiocarp is the reproductive structure that holds the basidium, it is usually a stalk with a cap facing downward.
An ascocarp is a cup like structure that holds the ascus.
3) Describe three different kinds of Asexual Reproduction found in fungi (6).
Some unicellular fungi can reproduce by mitosis.
Yeast cells reproduce by a process called budding. An asexual process in which part of the cell pinches itself off to produce small offspring.
Most fungi can grow from a small piece of mycelium called fragmentation.
Most fungi can reproduce asexually by spores.
4) Describe the reproduction of Ascomycetes (3). At the very least be able to identify it.
Sac fungi reproduce asexually by forming spores at the tips of their hyphae.
Sac fungi reproduce sexually by forming an ascus – a sac structure in which spores are formed.
Sexual reproduction takes place when the hyphae of two compatible mating types form male
(antherdium) and female (ascogonium) haploid gametangia. As the ascogonium and antehridium approach one another, a tube forms between them and the nuclei from the antheridium cross and enters the ascogonium. The parent fungi form a visible cup-like reproductive structure called the
ascocarp that holds the sacs called asci which develop at the tips of the hyphae and form
ascospores which are released.
5) Describe the reproduction of Zygomycetes (3). At the very least be able to identify it.
When hyphae of different mating types or strains grow close to each other the mold may reproduce sexually by conjugation. The mold develops special extension for mating called
gametangium. The gametangia from the two types grow together and fuse. Nuclei from the two types mix and form a thicked walled structure called a zygosporangium which is a resting stage
(becomes dormant) of a fungus that contains many nuclei. A zygosporganium can survive hostile environmental conditions. When conditions improve, the diploid zygosporangium cracks open and a
sporangiophore grows and forms a sporangium. The sporangium releases thousands of haploid spores.
6) Explain if fungi they are heterotrophs or autotrophs and what that means (define), explain whether or not they are saprophytes (define), and summarize how fungi obtain their nutrients (6)?
All fungi are heterotrophs obtaining their nutrition from other organisms.
Most fungi are saprophytes, they obtain their nutrients by digesting and absorbing nutrients from dead organisms. Fungi are decomposers.
Fungi digest their food outside of their bodies by secreting enzymes that break down organic material. The fungi then absorbs food through their cell walls. Like animals, fungi store energy in the form of glycogen
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Name: Total /47
7) Explain why lichens are important to the environment (2).
Lichens absorb chemical nutrients, such as nitrogen and sulphur from the air. Because lichens absorb nutrients from the air they can grow on almost any surface. When lichens grow on bare rock, they help breakdown rock to soil.
8) How does gametangium differ from a zygosporangium (1)?
Gametangia are haploid hyphae that grow together and fuse to form a diploid zygosporangium, which is thick walled so it can go into a dormant state.
9) What is mycorrhizae AND what ecological role does it play/what are their benefits (2)?
Mycorrhizae is a symbiotic association between a fungus and plant roots. They benefit the plant and fungi by providing nutrients to both.
10) Identify ONE Way in which fungi differ from organisms in each of the other KINGDOMS of
Eukaryotic Organisms (6).
Protista  Fungi are mostly multicellular whereas the protista are usually unicellular
Plantae  Fungi are heterotrophs whereas plants are photosynthestic; fungi have chitin in their cell walls whereas plants have cellulose
Animalia  Fungi digest their food outside their bodies then absorb the nutrients whereas animal ingest their food then digest it inside their bodies; fungi have cell walls but animals do not
11) What characteristic makes fungi an important resource recycler in the environment (1)?
The ability of the fungi to break nutrients into their basic compounds and elements.
12) Explain why being able to reproduce both Sexually and Asexually is an adaptive advantage
(4).
The ability to reproduce both sexually and asexually is an adaptive advantage because if the fungi is living in ideal conditions the asexual form will be able to reproduce quickly to take advantage of the environment.
The ability to reproduce sexually allows for transfer of genetic information but also will allow the fungi to survive when environmental conditions are not the best for the organism, so it can go into dormant state.
13) Explain the benefits plants and fungi derive from a mycorrhizal relationship (3).
The fungus benefits because it can absorb nutrients (sugars) made by the plant during photosynthesis, the fungus provides the plant two important advantages: (a) they hyphae of the fungus acts as root extensions. This increases the plants roots ability to absorb water from the soil; (b) the digestive enzymes secreted by the fungus help breakdown organic matter in the soil, which the plant can then absorb as nutrients and minerals.
14) Compare the type of hyphae that each of the fungal phyla have (3).
Zygomycota – coenocytic
Basidiomycota – septate
Ascomycota – septate or unicellular
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