Cell Biology

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BC35F Biotechnology of Industrial Ethanol
Production
Saccharomyces cerevisiae Cell Biology and
Biochemistry 1 (Continued)
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
S. cerevisiae cell wall properties Flocculati
on vs Buoyancy (flotation) Flocculation phenom
enon of asexual cellular aggregation in which
cells adhere reversibly to form marcoscopic
flocs, which sediment out of suspension. Bottom
yeasts (lager beers) flocculate Top yeasts (ales)
are buoyant
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
S. cerevisiae cell wall properties Flocculat
ion brought about by flocculins cell surface
glycoproteins which bind to cell surface
mannoproteins, similar in action to
lectins. Agglomeration irreversible
aggregation, giving rise to baking industry
problems with dough leavening grit or sand.
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
Sporulation spore-formation induced in S.
cerevisiae by N-deprivation and supplying acetate
as respiratory substrate. Meiosis occurs and a
four-lobed nucleus forms, which gives rise to 4
spores.
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
Genome. Now complete sequence available. Dr
Ashby will discuss further. Extrachromosomal
DNA Mitochondrial (say no more!) 2 ?m DNA 60
copies of circular, histone-covered plasmids of
unknown function useful as cloning
vectors. Killer plasmids dsRNA encoding
toxins to kill sensitive strains 20s, 23s RNA
naked circular ssRNAs
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
MitochondriaOne, few or several? Not sure
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)
Vacuole. One or few? Isolated or linked to
E.R? Not sure. Functions Protein
turnover/trafficking Control of
Trehalose intracellular pH
control Storage of most nutrients
polyphosphate, basic amino acids, metal
ions uptake by proton antiport.
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BC35F Lecture 1 Cell Biology of S. cerevisiae
(continued)