Fungal Cells

Question 1

What percentage of angiosperm plants form a mycorrhizal symbiosis with fungi?

Answer 1

95%

Question 2

Name a group of fungi that are major killers of amphibians.

Answer 2

Chytrids

Question 3

What are the two major growth forms of fungi?

Answer 3

• Yeasts

- Hyphae

Question 4

Describe yeast cells.

Answer 4

• Unicellular

- Often rounded

Question 5

Describe hyphal cells.

Answer 5

• Elongated

- Usually multicellular

Question 6

What are dimorphic fungi?

Answer 6

Fungi that grow as yeasts and hyphae.

Question 7

Name the fungus that uses dimorphism to increase its pathogenicity.

Answer 7

Candida albicans

Question 8

What is required for fungal growth?

Answer 8

Delivery of vesicles to the growth region (bud or hyphal tip)

Question 9

How are vesicles delivered to the growth region of the fungus?

Answer 9

Using ‘fungal motors’ along the cytoskeleton

Question 10

Describe pseudohypha.

Answer 10

Yeast-like cells form a string, with no cell-cell communication.

Question 11

How are hyphal cells separated?

Answer 11

By septa

Question 12

How do:

a) Yeast cells grow?
b) Hyphal cells grow?

Answer 12

a) Yeast cells grow by isotrophic growth, known as ‘budding’.
b) Hyphal cells grow by polarised growth.

Question 13

Describe isotrophic growth.

Answer 13

Exocytosis occurs at the same rate all round the cell.

Question 14

Describe polarised growth.

Answer 14

Exocytosis is faster at one end of the cell.

Question 15

What is the disadvantage of hyphal fungi?

Answer 15

If one cell dies, the whole hypha dies

Question 16

What is different about the cytoskeleton of a yeast cell?

Answer 16

It has no microtubules, because it is smaller, so no need for long-range transport.

Question 17

What are actin patches involved in?

Answer 17

Endocytosis

Question 18

What is chitin synthase used for in fungal cells?

Answer 18

To make chitin, a component of fungal cell walls

Question 19

How often to vesicles arrive at a tip containing chitin synthase?

Answer 19

1 vesicle per minute

Question 20

What is the Spitzenkörper?

Answer 20

A structure found in hyphae which serves as a ‘vesicle supply centre’ and controls where next exocytosis goes.

Question 21

Who discovered there Spitzenkörper?

Answer 21

Reinhardt

Question 22

In what fungi are Woronin bodies found?

Answer 22

Ascomycetes

Question 23

Describe the concept of Woronin bodies.

Answer 23

Damaged cells in a hypha are isolated by ‘plugs’ in the septa called Woronin bodies, preventing other cells in the hypha from dying

Question 24

What are Woronin bodies derived from?

Answer 24

Peroxisomes

Question 25

What are Woronin bodies composed of?

Answer 25

Hexagonal crystals of the protein Hex1

Question 26

What is the size range of the hexagonal crystals found in Woronin bodies?

Answer 26

150-500nm

Question 27

How do hyphal cells exchange material?

Answer 27

Via septal pores

Question 28

Give a fungal-specific enzyme that synthesises the cell all at the growing hyphal tip.

Answer 28

Beta-1,3-D-glucan synthase

Question 29

Describe how fungi organise their nuclei.

Answer 29

• Do not contain nuclear lamina

- Instead, actively move nuclear pores and associated chromosomes