Fungi Key Facts

Question 1

What size are yeast cells typically ?

Answer 1

5-10 micrometers

Question 2

What type of nutrition do fungi use ?

Answer 2

Heterotrophy - by degrading complex organic molecules

Question 3

What are the types of heterotroph subtypes of fungi ?

Answer 3

Saprophytes - derive nutrients from dead remains

Necrophytes - derive nutrients from organisms
Biotrophs - derive nutrients from living host

Question 4

How do plants and fungi differ ?

Answer 4

Plants are photoautotrophs
Fungi secrete enzymes and digest/absorb organic material

Fungi - usually filamentous
P - box like

F- nuclear envelope doesn’t break down for mitosis
P- nuclear envelope breaks down

Question 5

Are yeast multi or singe cell ?
What shape ?

Answer 5

Single cell
Oval or spherical

Question 6

Do yeast reproduce asexually or sexually ?
Do they form a colony ?

Answer 6

Asexually

Can aggregate to form a colony / pseudohyphae

Question 7

Are filamentous fungi multicellular ?
What is a mycelium ?
How does reproduction occur ?

Answer 7

Yes
Colony or mass of hyphae
Via spores

Question 8

In fungal sexual reproduction when does this tend to occur ?

Answer 8

When nutrients are in poor supply

Question 9

What is heterothallism?

Answer 9

Results in exchange of genetic material and requires two different mating types

Question 10

What is homothallism ?

Answer 10

Some fungi can self-fertilise and produce sexual spores

Question 12

Describe sexual reproduction in fungi

Answer 12

Hyphal / cytoplasm fusion
Dikaryon (n+n)
Fusion of nuclei diploid (2n)
Meiosis restores haploid state resulting in haploid sexual spores and germination

Question 13

What are the 3 main phyla of fungi ?

Answer 13

Zygomycota
ascomycota
Basidomycota

Question 14

Describe asexual reproduction in zygomycetes

Answer 14

1. Aerial hypha produces a sporangium
2. Sporangium bursts to release
   Spore germinates to produce aseptate mycelium
   Vegetative mycelium grows
   Gamete forms at tip of hyphae

Question 15

Describe sexual reproduction in zygomycetes

Answer 15

5. Gamete forms at tip of hyphae (1n)
6. Mating hyphae join and fuse (n +n )
7. Zygosporangium (2n)
8. Mature zygosporangium
9. Nuclear meiosis
10. Zygosporangium produces an asexual sporangium (n)
11. Spores (n) are released from the sporangium
12. Spore germinates to produce mycelium

Question 16

What is the smallest phyla of fungi ?
Septate or aseptate ?
Asexual spore type
Sexual spore type

Answer 16

Zygomycetes
Aseptate
Haploid sporangiospores
Diploid Zygospores

Question 17

Are ascomycetes septate or aseptate ?
What are the asexual features ?
Sexual features ?
What are most ascomycetes?

Answer 17

Septate
Haploid conidospores
Haploid ascospores (meiosis followed by mitosis)
Saprophytes

Question 18

Are basidiomycetes Septate or aseptate ?
Sexual features as asexual is uncommon ?
What do they have?

Answer 18

Septate hyphae (dikaryons)
Haploid basidiospores (meiosis)
Fruiting body such as basidiocarps e.g toadstools , brackets and puffballs

Question 19

What nutritional type are most basidiomyctes ?

Answer 19

Saprophytes e.g lignin dercomposers

Question 20

What are deuteromycetes?

Answer 20

Sexual reproduction cycle is absent

Asexual spores produced in various ways
Fungi imperfecti - they lack a sexual cycle

Question 21

What can fungi control ?

Answer 21

Insect pests
Phytopathogenic fungi

Question 22

What is the cycle of typical infection for fungi to control insect pests ?

Answer 22

1. Spore attachment
2. Germination to intersegmental region
3. Penetration of cuticle
4. Hyphal invasion
5. Sporulates
6. Proliferation in to blood (yeast phase)
7. Death (toxins/sugar levels)
8. Saprophytic stage - spores

Question 23

What is an example of a fungi that is used to control insect pests ?

Answer 23

Verticillium lecanii
Kills whitefly and aphids

Question 24

How does verticillium kill insects ?

Answer 24

Produces spores in liquid fermentors
Fresh spores are sticky , they attach to the insect, which becomes contagious
Spores do not need to be ingested

Question 25

What are the mechanisms of control in phytopathogenic fungi ?

Answer 25

Parasitism of the pathogen by the BCA Production of antibiotics, BCA poisons the pathogen Competition for nutrients, water, space

Question 26

What are mycoparasites ?

Answer 26

Fungi that parasitize other fungi - ‘ mycoparasites’ (many are zygomycetes which are biotrophic and produce haustoria )

Question 27

What fungi Is in marmite ?

Answer 27

S.cerevisiae

Question 28

What product is formed by fermentation of beans with Aspergillus oryzae?

Answer 28

Soy sauce Beans soaked Aerobic fermentation A.oryzae Anaerobic fermentation with Zygosaccharomyces Drained and pasteurised

Question 30

What fungi does Quorn use ? What does it use to grow ?

Answer 30

Fusarium graminearum In 1980 Glucose syrup Ammonia - nitrogen source

Question 31

What enzymes are produced commercially by Aspergillus niger?

Answer 31

Glucoamylases : liquid starch to high glucose syrup (baking soda, brewing , mycoprotein) Pectinases ( fruit juices) Glucose oxidase (food preservation) , diagnostic tests Phytases ( improvement of animal feed)

Question 33

What carcinogen do starch based foods cooked at high temperature have ?

Answer 33

Acrylamide - carcinogen

Question 34

What does acrylaway do?

Answer 34

Lowers acrylamide

Question 35

Aspergillus Niger produce s which commercially important acid ?

Answer 35

Citric acid

Question 36

What are statins ?

Answer 36

Fungal metabolites that inhibit the biosynthesis of cholesterol and are used to reduce plasma cholesterol levels

Question 37

Trichoderma spp. produce what ?

Answer 37

Antibiotics