NO.3/Sac
Life Science 13
Vocabulary
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Life Science 13
1.dikaryon- a cell with two haploid nuclei.
2.haploid nuclei- a nucleus with only half the normal a
ctual number of chromosomes
3.nuclear fussion- the process in which two or more
atomic nuclei join together, or "fuse", to form a
single heavier nucleus
4.Ascus- a sac-like structure produced by fungi
5.digestive enzymes- enzymes that break down
polymeric macromolecules into their smaller building
blocks.
6.conidia- asexual unchangeable fungus spores
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Life Science 13
 Fungi
 Members of “Ascomycota”
 Reproduce
Sexual reproduction
Asexual reproduction
 Produce spores in their ascus(seed bag)
 Commonly cylinder-shaped large cell
 Inside , there’re 8 ascospores
 Both multicellular & unicellular
 Have dissepiment- dividing membrane
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Life Science 13
•Body part :
Fruiting
bodies
Reproduction
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Life Science 13
Sexual
Step 1- compatible hyphae fuse together
Step 2- nuclei from the different hyphae move together in
to one cell to form a *dikaryon.
Step 3- cell divisions occur, several cells with two differen
t haploid nuclei per cell form.
Step 4- *nuclear fusion of the two haploid nuclei occurs in
the ascus mother cell.
Step 5- the ascus mother cell develops
into an *ascus
Step 6-meiosis occurs in the diploid cells and, four or eig
ht haploid ascospores form in the ascus
Reproduction
Asexual
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Life Science 13
Asexual reproduction among the different group
s of fungi are very similar.
• Ascomycota reproduce asexually through
budding or the formation of *conidia.
conidia- asexual uncha
ngeable fungus spores
How they eat/ get food
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Life Science 13
• Require organic molecules as energy sources. They get thes
e by feeding on dead things.
• To obtain these nutrients , sac fungi deposit
powerful *digestive enzymes.
• They are heterotrophs
Something cool
NO.3/Sac
Life Science 13
Ergot (a type of sac fungi) has been known and used for many centuries, and it w
as even described in an Assyrian tablet as the "noxious pustule in the ear of grai
n." In ancient times ergot was also known as "mad grain" and "drunken rye." The
n later in European history, there were periodic plagues, which had many sympto
ms, depending on the dosage of ergot. The possible effects were (mild to severe)
: (1) burning and convulsions, (2) hallucinations with imaginary sounds, (3) gangr
ene and loss of limbs, (4) permanent insanity, and, occasionally, (5) death. The in
itial burning sensation led to the Latin name ignis sacer, which means holy fire. T
his human malady was so horrible that in 1093 a religious order was founded in s
outhern France to help those afflicted; St. Anthony was the patron saint, so the m
alady, now called ergotism, was then named St. Anthony's fire.
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NO.3/Sac
Life Science 13