lecture 7 Fungi (Morphology, Physiology, Life cycle)

Question 1

Fungi are…

Answer 1

• Eukaryotic organisms
• Nonphotosynthetic
• Nonmotile (except for a small proportion of life
  stage)

Question 2

Morphological characteristic of fungi

Answer 2

• Body Forms:
  
  • Unicellular (yeasts)
  • Filamentous structures called hyphae
  • Aggregation of hyphae forms mycelium
• Special Structures:
  
  • Sclerotium: hardened mass of mycelium for
    overwintering
  • Multicellular structures like rhizomorphs, fruiting
    bodies, and mushrooms

Question 3

Are fungi Autotrophs or Heterotrophs?

Answer 3

Heterotrophs

Question 4

Heterotrophs

Answer 4

Depend on external sources for nutrients.

Question 5

what are Saprophytes or Saprobes

Answer 5

Consume dead tissues or organic waste, acting as decomposers.

Question 6

Symbionts

Answer 6

Engage in mutually beneficial relationships, like mycorrhizal associations.

Question 7

Parasites

Answer 7

Feed on living tissues of plants or animals.

Question 8

Pathogens

Answer 8

If the feeding behavior of a parasite causes disease in the host organism.

Question 9

Heterotrophic Absorption in Fungi

Answer 9

Process:
- Active transport mechanisms are employed for nutrient absorption.
- Hyphae release enzymes that break down substrates like cellulose, lignin, proteins, and lipids.
- Digestion products- disaccharides,
monosaccharides, amino acids, oligopeptides, and small lipid molecules.
- Fungal cells reabsorb these products.
- Food Storage: Glycogen is used to store food materials.

Question 10

Fungal Hypha

Answer 10

• Tubular structures are interconnected via septums (plural septa)
• Chitin cell wall
• Multinucleate
• Grows through hyphal tip

Question 11

Fungal Cell Wall - Composition

Answer 11

Chitin: Provides strength and shape, made of N-acetylglucosamine β-1,4 linkage.
β-1,3 Glucans: Extends throughout the cell wall.

Question 12

Fungal Cell Wall - Outer Layer

Answer 12

Contains N- and O-linked oligosaccharides like mannans associated with glycoproteins.
GPI Anchors: Some glycoproteins use GPI anchors to attach to the plasma membrane or inner wall.

Question 13

What are the two major types of reproduction in fungi

Answer 13

Asexual Sporulation
Sexual Sporulation

Question 14

Asexual Sporulation origin

Answer 14

Mitotic origin, involves mycelial fragmentation or direct asexual sporulation.

Question 15

Asexual Sporulation advantages

Answer 15

Clonal Population
Adapted to Environment
Quicker Dispersal
Less Energy Consuming

Question 16

Clonal Population

Answer 16

the offspring are genetically identical to the parent.
can be advantageous in maintaining favorable traits within a population.

Question 17

Sexual Sporulation

Answer 17

Meiotic origin.
More Energetically Costly
Differentiates Major Fungal Groups
Classification Based on Fruiting Bodies (Asci or Basidia)

Question 18

Sexual Sporulation advantage

Answer 18

Results in Greater Genetic Diversity

Question 19

Sexual reproduction in fungi

Answer 19

1.Fusion of 2 hyphae with different mating types
2.Exchange of nuclei
3.Dikaryotic phase
4.Fusion of 2 nuclei
5.Diploid zygote
6.Meiosis or Mitosis
7.Production of sexually formed spores

Question 20

Life cycle of an asexual fungus

Answer 20

Spores
Germination
Mycelium
Spore producing structures

Question 21

Life cycle of a sexual fungus

Answer 21

Spores
Mycelium
Plasmogamy (fusion of cytoplasm)
Dikaryotic stage
Karyogamy (Fusion of nuclei)
Diploid stage
Meiosis
Spore producing structures

Question 22

How many fungal phyla are there ?

Answer 22

5

Question 23

Fungal phyla distinguished by?

Answer 23

Reproductive features

Question 24

Name the 5 fungal phylum

Answer 24

Chytridiomycota (chytrids)
Zygomycota (Zygote fungi)
Glomeromycota (arbuscular mycorrhizal fungi)
Ascomycota (sac fungi)
Basidiomycota (club fungi)