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Biology for Advanced Level Secondary Schools

(a) It has chloroplast that contains phylum are fungi-like protoctists such as
chlorophyll for photosynthesis. Phytophthora, Puccinia and Pythium.

(b) It sometimes behaves as heterotroph
due to possession of a gullet with General characteristics of phylum
sphincter and reservoir. Oomycota
(a) They are filamentous protoctists
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(c) It can swim using flagella. which must absorb their food from
(d) It has a flexible pellicle for maintenance the surrounding water or soil, or may
of shape and for euglenoid movement. invade the body of another organism
to feed.
(e) It possesses contractile vacuole for
osmoregulation. (b) They are mostly parasites of plants,
example Phytophthora infestans that
(f) It has a high (rapid) rate of multiplication
during favorable conditions and forms causes serious diseases such as potato
cysts under unfavorable conditions to blight disease.
ensure survival. (c) They reproduce sexually by oogamy
(g) It has a photoreceptor for detection of in which male and female gametes
light conditions. fuse to form an oospore.
(d) The general body is organised into

Exercise 3.6 mycelia with aseptate or coenocytic
hyphae.
1. Euglena is believed to be the (e) They have cell walls made up of
origin of both plants and animals. cellulose.
Explain.
(f) They have a tubular structure called
2. Describe the structure of Euglena.
a haustorium used for absorption of
3. Explain the adaptations of Euglena nutrients from the host (Figure 3.17).
to its mode of life.

Distinctive features of phylum Oomycota
Phylum Oomycota Oomycota can be distinguished from other
The phylum includes fungus-like members of the group by the following
organisms, which are also referred to as features:
“water molds”. Normally oomycetes may (a) They have sporangia, which produce
occur as saprotrophs; living on decayed zoospores.
matter or parasites living on higher (b) Their zoospores have two flagella

plants and can be aquatic, terrestrial or attached to a ventral groove; the
amphibious. Oomycetes play an important anterior flagellum is a tinsel, while the
role in the decomposition and recycling posterior one is a whiplash type.
of decaying matter. Members of this

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