fungi

human uses of fungi

One way we use fungi is by eating them. Many species of mushrooms are edible. Yeasts are used for break making. Other fungi are used to ferment foods, such as soy sauce and cheeses. You can see the fungus growing through the blue cheese in Figure 9.14. The fungus gives the cheese its distinctive appearance and taste. People also use fungi: to produce antibiotics. to produce human hormones such as insulin. as natural pesticides. as model research organisms.

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fungi and human diseases

Several common human diseases are caused by fungi. They include ringworm and athletes foot, both shown in Figure 9.15. Ringworm isnt caused by a worm. Its a skin infection by a fungus that leads to a ring-shaped rash. The rash may occur on the head, neck, trunk, arms, or legs. Athletes foot is caused by the same fungus as ringworm. But in athletes foot, the fungus infects the skin between the toes. Athletes foot is the second most common skin disease in the U.S.

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fungi and people

Fungi may cause disease in people as well as other organisms. On the other hand, people have been using fungi for thousands of years.

asexual reproduction in fungi

During asexual reproduction, fungi produce haploid spores by mitosis of a haploid parent cell. A haploid cell has just one of each pair of chromosomes. The haploid spores are genetically identical to the parent cell. Spores may be spread by moving water, wind, or other organisms. Wherever the spores land, they will develop into new hyphae only when conditions are suitable for growth. Yeasts are an exception. They reproduce asexually by budding instead of by producing spores. An offspring cell forms on a parent cell. After it grows and develops, it buds off to form a new cell. The offspring cell is genetically identical to the parent cell. You can see yeast cells budding in Figure 9.11.

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fungi reproduction

Most fungi reproduce both asexually and sexually. In both types of reproduction, they produce spores. A spore is a special reproductive cell. When fungi reproduce asexually, they can spread quickly. This is good when conditions are stable. They can increase their genetic variation by sexual reproduction. This is beneficial when conditions are changing. Variation helps ensure that at least some organisms survive the changing conditions. Figure 9.10 shows how asexual and sexual reproduction occur in fungi. Refer to the figure as you read about each of them below.

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roles of fungi in ecosystems

Most fungi grow on moist soil or rotting vegetation such as dead logs. Some fungi live in water. Others live in or on other organisms. Fungi get their nutrition by absorbing organic compounds from other organisms. The other organisms may be dead or alive, depending on the fungus.

sexual reproduction in fungi

Sexual reproduction also occurs in most fungi. It happens when two haploid hyphae mate. During mating, two haploid parent cells fuse. The single fused cell that results is a diploid spore. It is genetically different from both parents. The spore undergoes meiosis to form haploid daughter cells. These haploid cells develop into new hyphae.

fungi symbiosis

Many fungi get organic compounds from living organisms. They have close relationships with other species. A close relationship between two species is called a symbiotic relationship. Two symbiotic relationships in fungi are mycorrhiza and lichen. These relationships are beneficial for both species. Mycorrhiza is a relationship between a fungus and a plant. The fungus grows in or on the plants roots. The fungus benefits from easy access to food made by the plant. The plant benefits because the fungal hyphae absorb water and nutrients from the soil that the plant needs. Lichen is a relationship between a fungus and cyanobacteria or green algae. The fungus grows around the bacterial or algal cells. The fungus benefits by getting some of the food made by the photosynthetic cells. The bacteria or algae benefit by getting some of the water and nutrients absorbed by the fungus. You can see a picture of lichen in Figure 9.12. Some fungi have a different kind of relationship with plants. They are plant parasites. They get food from the plants and cause harm to the plants in return. Fungi are the major causes of disease in agricultural crops. They may eventually kill their plant hosts. Some fungi are animal parasites. The wasp in Figure 9.13 is infected with a fungus. The fungus is the white fuzzy matter on the dark brown moth.

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what are fungi

Fungi (fungus, singular) are relatively simple eukaryotic organisms. They are placed in their own kingdom, the Fungus Kingdom. Most fungi are multicellular organisms. These fungi are called molds. However, some fungi exist as single cells. These fungi are called yeasts. You can see examples of different types of fungi in Figure 9.7. For a funny, fast-paced overview of fungi, watch this video: . MEDIA Click image to the left or use the URL below. URL:

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classification and evolution of fungi

For a long time, scientists classified fungi as members of the Plant Kingdom. Fungi share several obvious traits with plants. For example, both fungi and plants lack the ability to move. Both grow in soil, and both have cell walls. Some fungi even look like plants.

fungi classification

Today, fungi are no longer classified as plants. We now know that they have important traits that set them apart from plants. Thats why they are placed in their own kingdom. How do fungi differ from plants? The cell walls of fungi are made of chitin. Chitin is a tough carbohydrate that also makes up the outer skeleton of insects. The cell walls of plants are made of cellulose. Fungi are heterotrophs that absorb food from other organisms. Plants are autotrophs that make their own food. The Fungus Kingdom is large and diverse. It may contain more than a million species. However, fewer than 100,000 species of fungi have been identified.

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fungi evolution

The earliest fungi evolved about 600 million years ago. They lived in the water. Fungi colonized the land around the same time as plants. That was probably between 400 and 500 million years ago. After that, fungi became very abundant on land. By 250 million years ago, they may have been the dominant life forms on land.

structure of fungi

Yeasts grow as single cells. Other fungi grow into multicellular, thread-like structures. These structures are called hyphae (hypha, singular). You can see a photo of hyphae in Figure 9.8. They resemble plant roots. Each hypha consists of a group of cells surrounded by a tubular cell wall. A mass of hyphae make up the body of a fungus. The body is called the mycelium (mycelia, plural). A mycelium may range in size from microscopic to very large. In fact, the largest living thing on Earth is the mycelium of a single fungus. Nicknamed the humongous fungus, it grows in a forest in Oregon. A small part of the fungus is pictured in Figure 9.9. The giant fungus covers an area of 2384 acres. Thats about the size of 1,665 football fields! The fungus is estimated to be at least 2400 years old, but it could be much older.

fungi as decomposers

Most fungi get organic compounds from dead organisms. Fungi use their hyphae to penetrate deep into decaying organic matter. They produce enzymes at the tips of their hyphae. The enzymes digest the organic matter so the fungal cells can absorb it. Fungi are the main decomposers in forests. They are the only decomposers that can break down cellulose and wood. They have special enzymes for this purpose.

instructional diagrams

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The diagram shows the asexual and sexual reproduction cycle of Fungi. In both types of reproduction, they produce spores which are a special reproductive cell. A mass of hyphae makes up the body, or mycelium, of the fungus. During asexual reproduction, mycelium produce haploid spores by mitosis through spore-producing structures of a haploid parent cell. The haploid spores are genetically identical to the parent cell. After germination, spores develop to become mycelium. Sexual reproduction occurs when two haploid hyphae mate, and undergo plasmogamy (fusion of cytoplasm) to reach the heterokaryotic stage. Karyogamy (fusion of nuclei) then occurs to form a diploid cell called zygote. It then undergoes meiosis to form spores. The spores then undergo germination to become mycelium and the cycle continues.

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This diagram shows the asexual and sexual process of a fungi. Fungi can reproduce either of the two depending on the growth condition of the fungi. If the growth condition is stable, the fungi undergoes asexual reproduction. In asexual reproduction, the mycelium produces haploid spores via mitosis. These spores then spread themselves by air, water or other organisms. Once the spores landed on a place with stable growth condition, they will develop into new hyphaes. On the other hand, if the growth condition keeps changing, the fungi will exhibit sexual reproduction. Two haploid mycelia will fuse via plasmogamy and karyogamy, thus creating a diploid spore. This spore then produces haploid daughter cells via meiosis, which can then be developed into new hyphaes.

questions

All of the following are fungi except

-->  a. algae

b. mushrooms

c. puffballs

d. bread molds

Which of the following is a fungus?

a. slime mold

b. water mold

-->  c. bread mold

d. all of the above

Which of the following is true of all fungi?

a. They are multicellular organisms

-->  b. They are heterotrophs

c. They reproduce by budding

d. all of the above

Fungi were originally classified as

-->  a. plants

b. protists

c. animals

d. prokaryotes

All fungi are

a. multicellular organisms

-->  b. heterotrophs

c. parasites

d. decomposers

How are fungi similar to plants?

a. They cannot move on their own

b. They often grow in soil

c. They have chloroplasts in their cells

-->  d. two of the above

When did the earliest fungi evolve?

-->  a. 600 million years ago

b. 260 million years ago

c. 60 million years ago

d. 6 million years ago

When fungi reproduce sexually

a. two diploid hyphae mate

b. each parent produces haploid gametes

-->  c. the parents create a diploid spore

d. a mycelium releases haploid spores into water

Foods made with the help of fungi include

a. blue cheese

b. soy sauce

c. bread

-->  d. all of the above

Mycorrhiza is a relationship between a fungus and a

a. cyanobacterium

b. green alga

-->  c. plant

d. wasp

Athletes foot is

-->  a. a skin infection

b. very rare in the U.S

c. caused by a different fungus than ringworm

d. characterized by a rash on the hands, legs, and feet

Fungi can be used to produce

a. antibiotics

b. human hormones

c. natural pesticides

-->  d. all of the above

_Fungi obtain nutrients by absorbing organic compounds.

-->  a. true

b. false

_Fungi used to be placed in the Animal Kingdom.

a. true

-->  b. false

_Fungi have cell walls made of cellulose.

a. true

-->  b. false

_All fungi are heterotrophs.

-->  a. true

b. false

The earliest fungi evolved about 250 million years ago.

a. true

-->  b. false

Some fungi cause human diseases.

-->  a. true

b. false

_Mycelia are always very large.

a. true

-->  b. false

People have used fungi to produce antibiotics.

-->  a. true

b. false

_Most fungi reproduce both sexually and asexually.

-->  a. true

b. false

_Fungi are the only organisms that can decompose wood.

-->  a. true

b. false

_There are only about 10,000 species in the Fungus Kingdom.

a. true

-->  b. false

Fungi have special enzymes for decomposing cellulose.

-->  a. true

b. false

___thread-like, multicellular structure produced by a fungus

a. mycelium

b. spore

c. chitin

d. symbiosis

e. yeast

f. budding

-->  g. hypha

___method of asexual reproduction in yeasts

a. mycelium

b. spore

c. chitin

d. symbiosis

e. yeast

-->  f. budding

g. hypha

___tough carbohydrate that makes up the cell walls of fungi

a. mycelium

b. spore

-->  c. chitin

d. symbiosis

e. yeast

f. budding

g. hypha

___close relationship between two species in which at least one species benefits

a. mycelium

b. spore

c. chitin

-->  d. symbiosis

e. yeast

f. budding

g. hypha

___body of a multicellular fungus

-->  a. mycelium

b. spore

c. chitin

d. symbiosis

e. yeast

f. budding

g. hypha

___reproductive cell produced by a fungus

a. mycelium

-->  b. spore

c. chitin

d. symbiosis

e. yeast

f. budding

g. hypha

___type of fungus that exists as single cells

a. mycelium

b. spore

c. chitin

d. symbiosis

-->  e. yeast

f. budding

g. hypha

diagram questions

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After a spore is released, what is the plants next stage?

a. sporangium

-->  b. young gametophyte

c. zygote

d. younge gametophyte

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The new sporophyte and gametophyte comes from what?

a. Sporangium

-->  b. Zygote

c. Mature sporophyte

d. Antheridium

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How many stages from Fertilisation to Meiosis?

a. 3

b. 6

c. 4

-->  d. 5

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How many zygotes are shown in the picture?

a. 2

-->  b. 1

c. 3

d. 4

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According to the image what occurs between spores and the appearance of sporangia?

a. Sporangia bursts

b. Sporangia appears

-->  c. Spores

d. Spores grow hyphae

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At what level are spores?

a. 4

b. 3

-->  c. 1

d. 2

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How many stages are there in a spore's life?

a. 3

-->  b. 4

c. 5

d. 2

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How many steps does it take for spores to develop sporangia?

a. 1

b. 3

c. 4

-->  d. 2

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At what process does the fusion of the cytoplasm occur?

-->  a. Plasmogamy

b. Karyogamy

c. Germination

d. Meiosis

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What comes after Dikaryotic Stage?

a. Spores

b. Meiosis

-->  c. Karyogamy

d. Germination

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What stage follows karyogamy?

a. Gemination

-->  b. Diploid stage

c. Plasmogamy

d. Dikaryotic stage

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How many phases does sexual reproduction have?

a. 8

-->  b. 9

c. 13

d. 10

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How many processes represented by purple bubbles are involved in sexual reproduction?

a. 1

b. 2

c. 3

-->  d. 4

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What happens after the diploid stage?

a. karyogamy

b. germination

-->  c. meiosis

d. plasmogamy

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How does a zygote become a basidium with four nuclei?

a. plasmogamy

b. germination

c. dispersal

-->  d. meiosis

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What happens to the Zygote (2n) to produce a Basidium with four nuclei (1n)?

a. Plasmogamy

-->  b. Meiosis

c. Dispersal and Germination

d. Cell Division

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How many basidiospores are formed after cell division?

a. 2

b. 3

c. 1

-->  d. 4

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How many stages of reproduction are between basidium and basidiospores?

-->  a. 2

b. 1

c. 6

d. 4

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What happens after the cell divides in basidiomycete life cycle?

a. Mycelia

-->  b. Dispersal and germination

c. Basidium

d. Basidiospores

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What happens to the spores after they grow hyphae?

a. Sporangia disappears

-->  b. Sporangia appears

c. Sporangia bursts

d. Sporangia dies

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How many phases does this fungus have in its life?

a. 3

b. 2

-->  c. 4

d. 5

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How many stages in the fungi life cycle are shown in the diagram?

a. 2

b. 1

c. 3

-->  d. 4

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What happens after sporangia appears?

a. nothing happens

b. spores

-->  c. sporangia bursts

d. spores grow hyphae

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What type of living organism is shown in the diagram?

a. Fish

b. Jellyfish

-->  c. Fungi

d. Bird

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What do Fungi produce during asexual reproduction?

a. Mycellium

-->  b. Spores

c. Germination

d. Meiosis

question_image

What does Germination lead to?

a. Plasmogamy

b. Spores

c. Meiosis

-->  d. Mycelium (n)

question_image

What process turns spores into mycelium?

a. karyogamy

-->  b. germination

c. plasmogamy

d. meiosis

question_image

How many kinds of fusion are shown in the diagram?

-->  a. 2

b. 1

c. 4

d. 3

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How many stages in the asexual reproduction?

a. 5

b. 3

-->  c. 4

d. 2

question_image

What is the following stage to Mycelium?

-->  a. Spore-producing structures

b. karyogamy

c. spores

d. dikaryotic stage

question_image

What is the process in which a haploid parent cell produces haploid spores during asexual reproduction?

a. Plasmogamy

-->  b. Mitosis

c. Meiosis

d. Germination

question_image

What does produce the spores?

a. Mycelium

b. Germination

-->  c. Mitosis

d. Karyogamy

question_image

How many steps are shown in the Fungi Life Cycle?

a. 5

-->  b. 6

c. 4

d. 7

question_image

How many types of reproduction are in the fungi life cycle?

-->  a. 2

b. 6

c. 5

d. 8

question_image

Put the processes involved in sexual reproduction of fungi in the correct order.

a. Plasmogamy -> Karyogamy -> Mitosis -> Germination

-->  b. Plasmogamy -> Karyogamy -> Meiosis -> Germination

c. Karyogamy -> Plasmogamy -> Mitosis -> Germination

d. Karyogamy -> Plasmogamy -> Meiosis -> Germination

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What is karyogamy?

-->  a. the nuclei fuse to form a diploid zygote

b. spores

c. haploid cells from two different mycelia fuse to form a heterokaryotic cell with two or more nuclei

d. a multi-cellular mycellium

question_image

What is the fusion of nuclei?

a. diploid

b. plasmogamy

c. spasmogamy

-->  d. karyogamy