Fungi

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This is a Biology Article
Image:Fungi diagram.png
Fungi
Subject	Biology
Section	The Organism
Note

A fungus is any eukaryotic organism that is a member of the kingdom fungi.

Contents 1 Rhizopus 1.1 Nutrition 1.2 Life Cycle 1.2.1 Asexual Reproduction 1.2.2 Sexual Reproduction 2 Saacharomyces (yeast) 2.1 Structure 2.2 Reproduction 2.2.1 Economic Importance of Yeast 3 Phytophthora 3.1 Structure 3.2 Life Cycle 3.3 Control Methods 4 Benefits of Fungi 4.1 Medical 4.2 Economic 5 Negatives of Fungi 5.1 Medical 5.2 Economic

Rhizopus

• The common bread mould
• It's cells:
  • Have vacuoles,
  • Contain many nuclei
  • Are aseptate (have no separating wall or membrane)
• It grows in strands known as Hyphae
• There are three types of Hyphae:

1. Stolons - grow on the surface of a substrate
2. Rhizoids - grow down from the stolon
3. Sporangiophores - grow up into the air

Nutrition

• Rhizopus is a saprophyte which get's it's nutrition from bread
• It does this by secreting digestive enzymes and then reabsorbing the food.

Life Cycle

Asexual Reproduction

Image:Rhizopus asexual reproduction.jpg

Sexual Reproduction

• There is no male of female, instead there's a + or a -
• They look alike, but are chemically different
• The conjugate much like the spirogyra, but this is quite rare

Saacharomyces (yeast)

Structure

• Saacharomyces is unicellular, which is uncommon in Fungi.
• It is found singularly or in groups
• It is ovoid in shape, with a diamater of 10mm

Reproduction

• Reproduction is asexual, through budding

1. A bud (bulge) forms on the side of the cell
2. The nucleus divides and moves into the bud, along with some cytoplasm
3. The bud separates, becoming a new cell

Economic Importance of Yeast

• Alcohol formation (Anaerobic Respiration)
• Baking industry - helps dough rise (Co2)
• Rich in Vitamin B

Phytophthora

• Phytophthora is a parasitic fungus that caused the potato famine.

Structure

Image:Phytophthora structure.jpg

Life Cycle

Image:Phytophthora life cycle.jpg

1. Develops in the stems and leaves of planted hubers
2. Attached by haustoria which absorb food from the cells of the host
3. Reproduces asexually in humid weather
4. The sporangia fall off
5. Develps further in two ways, depending on the temperature:
6. Low Temperature (12-15 Degrees Celcius)
   1. Sporangium develops Zoospores (with flagellae)
   2. These swim in a thin film of water
   3. Eventually they come to rest and germinate
7. High Temprature (18-22 Degrees)
   1. The whole sporangium falls as a single spore (conidium) which then germinates
8. In each case, the zoospore or condinium develops a germ tube
9. This then penetrates the host (through the stomata or by peircing the epidermis)
10. Once inside, a mycelium (group of hyphae) develops
11. The cycle starts again

Control Methods

1. Spraying with fungicides
2. Avoid planting infected tubers
3. Planting resistant types of potato
4. Spraying with corrosive solutions
5. Removing all potatoes at picking time, because blight can survive the winter

Benefits of Fungi

Medical

1. Antibiotics e.g. Penecillium notatum (penecillin)
2. Research
3. Produce important drugs

Economic

1. Decomposition
2. Brewing
3. Food industry:
   1. Some are edible e.g. Mushrooms
   2. Veined cheese
   3. Bakery

Negatives of Fungi

Medical

1. Cause Diseases
2. Poisonus to eat

Economic

1. Disease to crops
2. Deterioration to economic materials;
   1. Dry-rot of timber
   2. Foods
   3. Wallpaper etc.