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Flashcards in Eukaryotic Microbes Deck (73):
1

What domain are fungi in?

Eukarya

2

Do fungi contain sterols in their membranes?

Yes honey!

3

What are the multi-cellular and uni-cellular forms of fungi called?

Multi-cellular = molds and mushrooms. Uni-cellular = yeast

4

What nutrient type are yeast?

Chemoheterotrophs organic molecules are the carbon source and the energy source

5

What is the food acquisition method fungi use?

Absorptive (saprotrophic) - produce and secrete enzymes that degrade the substrate and the products are then absorbed

6

Fungi form symbiotic relationships. What does this mean?

It's a form of mutualism so both partners benefit

7

A symbiotic relationship fungi form with plants is called

Mycorrhiza

8

The symbiotic association composed of a fungus and the roots of a vascular plant consists of both partners benefiting. How?

The plant obtains minerals such as phosphates and the fungi obtains sugars/amino acids

9

There are two types of mycorrhiza, what are they?

Endomycorrhiza and ectomycorrhiza

10

What happens in endomycorrhiza?

The fungi penetrates the cortical cells of the roots for the symbiotic relationship

11

What happens in ectomycorrhiza?

The fungi surrounds the roots for the symbiotic relationship

12

Fungi can form a symbiotic relationship with green algae/cyanobacteria. How do they both benefit?

The algae/cyanobacteria gets nutrients and the fungi gets sugars

13

Fungi can play a role in pest control against...

Nematodes, weeds, mites and other fungi

14

Fungi are food both directly and indirectly. Explain this statement.

Mushrooms - directly. Indirectly - cultured foods.

15

Which fungi is used to make bread and beer?

Saccharomyces cerevisiae

16

Which fungi is used to make quorn?

Fusarium venenatum

17

Fungi can be used for medicinal purposes, what is an example of an antibiotic from a fungi?

Penicillin

18

Fungi can be used for medicinal purposes, what is an example of a immunosuppressive from a fungi?

Cyclosporins

19

Fungi can be used for medicinal purposes, what is an example of a bacteriostat from a fungi? Remember a bacteriostat prevents bacteria from multiplying without destroying them.

Fusidic acid

20

Fungi can be used for medicinal purposes, what is an example of a vasoconstrictor from a fungi?

Ergotamine

21

There are around 200 species of fungi that are pathogenic to animals and humans. Many are nosocomial (hospital acquired) Give some examples.

Aspergillosis, candidiasis, cryptococcosis, pneumocystis

22

What are mycotoxins?

They are compounds produced by some fungi that are toxic to humans/animals

23

Give two examples of a mycotoxin.

Amatoxins and aflatoxins

24

Where are amatoxins found?

Found in Amanita mushrooms - Amanita phalloides.

25

How are amatoxins fatal?

They are selective inhibitors of RNA polymerase II which is a vital enzyme in the synthesis or mRNA. Without mRNA which is the template of protein synthesis, cell metabolism stops. Causes kidney/liver damage too which is fatal.

26

What produces aflatoxins?

Aspergillus, A. flavus

27

How do aflatoxins cause liver failure (cirrhosis/carcinoma)?

The toxins can intercalate with DNA, damage DNA bases by alkylation (transfer of one alkyl group to another)

28

Why are fungi problematic when it comes to plants?

Thousands of species are plant pathogens - economic importance (rusts, smuts, mildews)

29

How can fungi be problematic when it comes to food?

They cause food spoilage

30

The fungal cell wall is...

unique

31

The fungal cell wall is present to protect the underlying

cytoplasm

32

The fungal cell wall determines and maintains the shape of the

fungal cell

33

The fungal cell wall acts as an interface between the fungus and the

environment

34

The fungal cell wall is the binding site for some

enzymes

35

The fungal cell wall allows interactions with other

organisms

36

The fungal cell wall is multi-

layered

37

What three layers make up the fungal cell wall?

Chitin, glucans and glycoproteins

38

What component makes up the smallest percentage of the fungal cell wall?

The chitin

39

What percentage of the fungal cell wall does chitin make up in yeast?

1-2%

40

What percentage of the fungal cell wall does chitin make up in multicellular yeast such as Neurospora and Aspergillus?

10-20%

41

What is chitin?

A polymer of N-acetylglucosamine

42

How does the N-acetylglucosamine molecules bind together to form a polymer in the fungal cell wall?

By forming chains - beta 1-4 linkages

43

How do the beta 1-4 linkages of N-acetylglucosamine forming the chains actually connect with others?

Through inter-chain hydrogen bondings which form microfibrils

44

What is the function of the chitin in a fungal cell wall?

To provide stability to the cell wall

45

What is glucans in a fungal cell wall?

A polymer of glucose

46

What percentage of a fungal cell wall is made up of glucans?

About 50-60%, it is a major component

47

What is glucans made of?

A polysaccharide of D-glucose

48

What linkage is between saccharide molecules making up the polysaccharide of glucans in the fungal cell wall?

Mostly beta 1-3 linked

49

What is the function of glucans in a fungal cell wall?

To function as an attachment site for other wall components

50

What percentage of the fungal cell wall is made of glycoproteins in yeast?

Around 30-50%

51

What percentage of the fungal cell wall is made of glycoproteins in filamentous fungi?

Around 20-30%

52

Where are the glycoproteins found in a fungal cell wall?

Tightly interwoven in the chitin/glucan matrix

53

Different fungi have different _____________ in their fungal cell wall

Glycoprotein

54

What type of glycoproteins are present in yeast?

Mannoproteins

55

What type of glycoproteins are present in N.crassa and A.fumigatus?

Galactomanno proteins

56

Glycoproteins allow adhesion to

surfaces

57

Glycoproteins protect the fungus from

chemicals

58

Glycoproteins allow the synthesis of other

cell wall components

59

How do fungal molds grow?

Grow as tube like, multi cellular filaments called hyphae

60

What are hyphae in soil called?

Vegetative hyphae

61

What is the role of hyphae?

To scavange nutrients

62

Vegetative hyphae grow together to form a compact mass. What is this mass called?

Mycelium

63

The portion of the hyphae that obtains nutrients is called the

vegetative hyphae

64

The portion of the hyphae concerned with reproduction is

the ariel hyphae - often bares reproductive spores

65

Why is the ariel hyphae called what it is?

The ariel hyphae projects above the surface of the medium.

66

There are two types of vegetative hyphae, what are they called?

Septate hyphae and coenocytic hyphae

67

Describe the septate hyphae.

The hyphae contain cross walls which divide them int distinct, uni-nucleate cell like units

68

Describe the coenocytic hyphae.

Hyphae contain no septa, forming long continous cells with many nuclei

69

Where do the vegetative hyphae grow from?

At the tip

70

The growing tip is special because of three reasons. What are these reasons.

Structurally and functionally very different from the rest of the hypha
The cytoplasm appears more dense
No major organelles

71

Where do vegetative hyphae grow from and what is this known as?

At the tip - apical growth

72

What does the growing tip of a vegetative hyphae contain?

A structure where Golgi-derived vesicles accumulate known as the Spitzenkorper

73

What is the Spitzenkorper?

The growing tip of a vegetative hyphae where the golgi vesicles accumulate