Fungi Characteristics

• Fungi are eukaryotic, non-photosynthetic, heterotrophic organisms.
• Most fungi are multicellular molds or unicellular yeasts.
• Fungal cell walls are composed of chitin.
• Fungal filaments called hyphae may have cross-walls (septa) or lack them (multinucleated).
• The fungal body, or mycelium, can be macroscopic or microscopic.

Bacteria vs. Fungi

• Fungi are generally larger than bacteria (four times bigger).
• Fungi have a nuclear membrane and organelles like mitochondria and endoplasmic reticulum, which bacteria lack.
• Fungal membranes contain sterols, while bacteria have a phospholipid bilayer.
• Fungal cell walls contain chitin, whereas bacteria have peptidoglycan.
• Fungi produce sexual spores (for reproduction) and asexual spores (for survival).
• Some fungi exhibit dimorphism (existing as both yeast and mold), unlike bacteria.
• Fungi require organic carbon and are not obligate intracellular pathogens
• Many bacteria can survive in anaerobic conditions, and do not require organic carbon.

Fungi vs. Other Eukaryotes

• Fungi belong to their own kingdom.
• Fungi are chemoheterotrophs, acquiring energy from chemical compounds and carbon from organic sources.
• Most fungi are multicellular, except for unicellular yeasts.
• Fungi can be unicellular, filamentous, or fleshy; protozoans are unicellular.
• Fungi acquire food by absorption.
• Fungi produce both sexual and asexual spores.

Clinical Classification

• Cutaneous mycoses affect the skin.
• Subcutaneous mycoses affect the subcutaneous tissue.
• Systemic mycoses infect internal organs.
• Opportunistic mycoses infect immunocompromised individuals.

Asexual Sporulation and Conidia Formation

• Conidia are asexual spores produced through mitosis.
• Mitosis produces genetically identical daughter cells, unlike meiosis.