Chapter 21 Fungi

Question 1

Main features of Fungi

Answer 1

Heterotrophic 
Multicellular 
Made up of hyphae
Hyphae form mycelium
Walls made of chitin

Question 2

Saprophytic fungi

Answer 2

Eat dead organic matter
Most fungi are sacrophytic
Recycle nutrients
Eg. Mushrooms and mould

Question 3

Parasitic

Answer 3

Absorb their food from living organisms
Causes harm to /weakens hosts
Eg. Athletes foot and ringworm

Question 4

Types of parasites:

1. Obligate
2. Facultative
3. Symbiotic

Answer 4

1. Live on host but doesn’t kill
   Eg. Athletes foot and ringworm
2. Kills the host and feeds on remains.
   Eg. Fungi on fruit
3. Both benefit

Question 5

Rhizopus structure

Answer 5

Sporangio spores
Sporangio phore 
Columella
Apophysis
Sporangium
Stolon 
Hyphae
Rhizoids 
Mycelium
Substrate

Question 6

Function of:

1. Hyphae
2. Rhizoids
3. Stolon
4. Sporangiophore

Answer 6

1. Digest substrate
2. More surface for absorption of digested material
3. Aerial hyphae allows rhizopus to grow sideways
4. Aerial hyphae allows rhizopus to grow up and reproduce

Question 7

Describe Asexual reproduction of rhizopus

Answer 7

1. Sporangiophore grows up from substrate after a couple of days.
2. Grows a sporangium.
3. Cells divide by mitosis to produce spores. Apophysis supports columella, which feeds the spores.
4. Sporangium dries out and releases spores.
5. Each spore grows into a new hyphae if it lands on a suitable substrate

Question 8

Sexual reproduction in rhizopus

Answer 8

Can only occur between +hypha and -hypha.

1. Hyphae of opposite strains grow close together.
2. Swellings form and touch.
3. Nuclei from hyphae move into swellings. Called progametangia.
4. Cross walls form, producing a gametangia.
5. The walls of the gametangia dissolve. Fertilisation takes place. Produces diploid zygote nuclei.
6. A zygospore forms around the nuclei.
7. When conditions suitable, the zygospore germinates by meiosis.
8. A hyphae grows and produces a sporangium. Spores develop and are released.

Question 9

Features of yeast

Answer 9

Tiny
Unicellular
Round

Question 10

Structure of yeast

Answer 10

Food vacuole
Nucleus
Vacuole- large for storage
Cytoplasm
Cell wall-made of chitin

Question 11

Describe reproduction in yeast

Answer 11

Asexual- budding
1. Nuclei of parent divides by mitosis
2. A swelling (bud) forms on the side.
3. One of the nuclei enters the bud.
4. The bud separates and becomes a new individual cell.
In some cases the bud does not separate but can itself bud. This forms a colony

Question 12

Benefits of fungi

Answer 12

Yeast used to make bread and alcohol.

As a source of food. Eg. Mushrooms

Question 13

Harmful effects of fungi

Answer 13

Causes animal diseases. Eg. Athletes foot and ringworm.
Spoils food. Eg. Rhizopus
Attacks crops

Question 14

Edible and poisonous fungi examples

Answer 14

Edible:
Field mushrooms
Morel
Truffle(below ground)

Poisonous:
Death cap mushroom
Destroying Angel mushroom
Causes damage to liver and intestine.

Question 15

What does aseptic and sterile mean? And name an example

Answer 15

Aseptic: Measures to exclude unwanted microorganisms.

Sterile: Is an environment where all microorganisms are destroyed.

Eg. Flaming the forceps. Cleaning the bench. Washing hands.