Page 20 - Science Class 08

mushrooms, cup fungi, and many other Yeasts are important as under:
kinds of microscopically small frui ng v Yeasts have a liking for acidic foods that
bodies). contain sugar.

There are over 100,000 species of fungi. Some v Yeasts can cause fermenta on to produce
other fungi are mildew and plant-rust. Fungi alcohols and carbon dioxide.
feeding on animals and plants are called
v Yeasts are used to raise dough for making
parasites. They steal nutrients from their hosts.
and baking bread.
Some fungi feed on decaying ma er on which
they grow. A third type of fungi live with other v Yeast are eaten to obtain nutrients like

organisms in mutually useful ways. They take protein and for B-vitamins.
carbohydrates from the organisms and supply v Yeast are used in making beer, wine and
them water and various minerals. As for other beverages.
reproduc on, they produce spores that are v Yeast are used to make vinegar, cheese and
dispersed by wind, water and animals. ace c acid.
How are Fungi Important? v A few yeast cause infec ons in humans.

v Fungi break down complex animal ma er Mycoplasma and ricke sias are two other
and plant ma er into simple compounds classes of disease producing microbes.
and enrich the soil for new plants.
Algae
v They return carbon dioxide to the air for
You must have seen a green layer of flora
the plants to use it in photosynthesis.
floa ng on the surface of a pond. It is, in fact, a
v Fungi like the mushroom and the truffle group organisms called algae (plural of alga).
are eaten as delicacies. Algae o en form a dark slippery coa ng in

v Fungi are used to give flavours to cheese. bathrooms if not cleared for days together.

v Some fungi cause diseases in plants, They can be of various shapes– round, rod-like,
animals and human beings. club-shaped or spindle-shaped. Also, they can
be green, blue-geen, brown or red. Remember
v Fungi like mildew destroy clothes, book-
that water of the Red Sea appears reddish
bindings and even wood.
because of algae floa ng on its surface.
v Moulds are fungi that are used in making
penicillin. Yeasts are unicellular fungi
present in soil as well as in air.

They can be stored in dry form for years. Yeast -
cells are of various shapes and sizes. A yeast
cell has a cell-wall, cytoplasm, nucleus, a large
vacuole, numerous granules and fat globules. It
is a Gram-posi ve microbe that reproduces
through budding or cell-division. Yeasts get
destroyed in air and in heat only up to 60°C.
Some insects also destroy them.
Algae

20 Science-8