Neha looks at two moulds under a microscope…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Neha looks at two moulds under a microscope. The black mould from stale bread has long hyphae with no cross walls and many nuclei along them. The blue-green mould from an old orange has hyphae divided by cross walls. Name the kind of hypha in each. To which class does each mould probably belong?
Need a reminder? The key ideaShow
A fungus has a mycelium of hyphae: septate (with cross walls) or coenocytic (no cross walls, many nuclei). The wall is of chitin and polysaccharides. Fungi are saprophytes, parasites or symbionts (lichens, mycorrhiza). Sexual reproduction: plasmogamy (two cells fuse, ), karyogamy (the nuclei fuse, ), then meiosis (haploid spores, ). Phycomycetes: aseptate, coenocytic mycelium, zygospores (Mucor, Rhizopus, Albugo). Ascomycetes, the sac fungi: septate mycelium, conidia, ascospores in asci (yeast, Penicillium, Aspergillus, Claviceps, Neurospora). Basidiomycetes: basidiospores on basidia (Agaricus, Ustilago, Puccinia). Deuteromycetes, the imperfect fungi: only the asexual stage is known (Alternaria, Colletotrichum, Trichoderma).
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The bread mould. No cross walls, many nuclei: coenocytic (aseptate) hyphae. This is Rhizopus, a Phycomycete.
Step 2. The orange mould. Cross walls: septate hyphae. This is Penicillium, an Ascomycete.
Answer: coenocytic (Phycomycetes) and septate (Ascomycetes).
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