MBY THEME 13,14,15
FUNGI, ALGAE AND PROTOZOA
FUNGI
• Mycology- the study of fungi
• They are Chemoheterotrophs
• An organism that uses organic chemical substances as a source of carbon and
energy
• Characteristics
• Vegetative structures of fungi
1. Molds and fleshy fungi
• Thallus body consist of hyphae ( filaments)
• Collection of hyphae is called a mycelium
a. Septate hyphae- contain cross-walls
b. Coenocytic hyphae- no septa
• Hyphae grow by elongating from the tip
• Vegetative hyphae obtain nutrients while aerial hyphae are involved with
reproduction
2. Yeasts
• Non-filamentous and unicellular
• Budding yeasts divide unevenly ( Saccharomyces cerevisiae)
• Fission yeasts divide evenly (Schizosaccharomyces pombe)
3. Dimorphic fungi
• One fungus can grow as a yeast or a mold, especially human pathogens
• Yeast phase triggered by environmental conditions
• Life cycle
• Reproduction can be sexual or asexual
• Reproduce by means of spores
o One fungal species can reproduce sexually and/or asexually and can have
several different spore types
o Different fungal groups have different spore types
o Spore types and forms were used until recently to classify fungi
• Asexual reproduction/spores
o Produced by mitosis and subsequent cell division
o No fusion of nuclei or genetic exchange
o Daughter cells genetically identical of the mother cells
o Asexual spores give rise to mycelium/colony that are genetically identical
to the parent spore
o Conidia- produced in a chain from a conidiophore and not enclosed in a
sac
o Arthroconidia: fragmentation of septate hyphae
o Ballistoconidia: buds of the parent cell
, MBY THEME 13,14,15
o Chlamydospore: spore within a hyphal segment
o Sporangiospores: enclosed in a sac
• Sexual reproduction/spores
o Produced fusion of nuclei of two opposite mating types
o Each spore differs genetically from other and parents
o Three phases of sexual reproduction:
1. Plasmogamy- cytoplasm of two parent cells fuse bringing together 2
haploid nuclei in the same cell
2. Karyogamy- the nuclei fuse and form diploid nucleus
3. Meiosis- diploid nucleus produce haploid nuclei (sexual spores)
o Zygomycota =Sexual spores – Zygospores
o Asexual spores- sporangiospores
o Dikaryomycota (separate hyphae)
1. Basidiomycota ( sexual spores are basidiospores; carries outside on
basidia)
• “club fungi” because sexual spores are produced externally on a structure called
the basidium, most often formed on a basidiocarp
2. Ascomycota ( sexual spores are ascospores; carried inside a sac)
• “sac fungi” because sexual spores ( ascospores) are produced in sac-like structure
called the ascus ( plural=asci)
• Reproduction – asexual = conidia
Sexual= Ascospores
FUNGI, ALGAE AND PROTOZOA
FUNGI
• Mycology- the study of fungi
• They are Chemoheterotrophs
• An organism that uses organic chemical substances as a source of carbon and
energy
• Characteristics
• Vegetative structures of fungi
1. Molds and fleshy fungi
• Thallus body consist of hyphae ( filaments)
• Collection of hyphae is called a mycelium
a. Septate hyphae- contain cross-walls
b. Coenocytic hyphae- no septa
• Hyphae grow by elongating from the tip
• Vegetative hyphae obtain nutrients while aerial hyphae are involved with
reproduction
2. Yeasts
• Non-filamentous and unicellular
• Budding yeasts divide unevenly ( Saccharomyces cerevisiae)
• Fission yeasts divide evenly (Schizosaccharomyces pombe)
3. Dimorphic fungi
• One fungus can grow as a yeast or a mold, especially human pathogens
• Yeast phase triggered by environmental conditions
• Life cycle
• Reproduction can be sexual or asexual
• Reproduce by means of spores
o One fungal species can reproduce sexually and/or asexually and can have
several different spore types
o Different fungal groups have different spore types
o Spore types and forms were used until recently to classify fungi
• Asexual reproduction/spores
o Produced by mitosis and subsequent cell division
o No fusion of nuclei or genetic exchange
o Daughter cells genetically identical of the mother cells
o Asexual spores give rise to mycelium/colony that are genetically identical
to the parent spore
o Conidia- produced in a chain from a conidiophore and not enclosed in a
sac
o Arthroconidia: fragmentation of septate hyphae
o Ballistoconidia: buds of the parent cell
, MBY THEME 13,14,15
o Chlamydospore: spore within a hyphal segment
o Sporangiospores: enclosed in a sac
• Sexual reproduction/spores
o Produced fusion of nuclei of two opposite mating types
o Each spore differs genetically from other and parents
o Three phases of sexual reproduction:
1. Plasmogamy- cytoplasm of two parent cells fuse bringing together 2
haploid nuclei in the same cell
2. Karyogamy- the nuclei fuse and form diploid nucleus
3. Meiosis- diploid nucleus produce haploid nuclei (sexual spores)
o Zygomycota =Sexual spores – Zygospores
o Asexual spores- sporangiospores
o Dikaryomycota (separate hyphae)
1. Basidiomycota ( sexual spores are basidiospores; carries outside on
basidia)
• “club fungi” because sexual spores are produced externally on a structure called
the basidium, most often formed on a basidiocarp
2. Ascomycota ( sexual spores are ascospores; carried inside a sac)
• “sac fungi” because sexual spores ( ascospores) are produced in sac-like structure
called the ascus ( plural=asci)
• Reproduction – asexual = conidia
Sexual= Ascospores
