Phaeophyceae - 2
1
Sexual reproduction in Phaeophyceae may be which of the following types?
Practice
A
Only isogamous
B
Only anisogamous
C
Isogamous, anisogamous or oogamous
D
Only oogamous
✅ Show Answer
✔ Correct Answer:
C
(Isogamous, anisogamous or oogamous)
💡 Explanation
Phaeophyceae: Dictionary meaning — a class of algae commonly known as brown algae.
Explanation — Phaeophyceae exhibit different types of sexual reproduction depending on the species, including isogamous, anisogamous and oogamous reproduction.
Isogamous: Dictionary meaning — sexual reproduction in which the two fusing gametes are similar in size and structure.
Explanation — In isogamous reproduction, the male and female gametes are morphologically similar.
Anisogamous: Dictionary meaning — sexual reproduction in which the two fusing gametes differ in size.
Explanation — In anisogamous reproduction, the gametes are unequal in size and generally differ in their characteristics.
Oogamous: Dictionary meaning — sexual reproduction involving a large non-motile female gamete (egg) and a small male gamete.
Explanation — Oogamous reproduction occurs in some members of Phaeophyceae, such as Fucus.
Given Statement - Sexual reproduction in Phaeophyceae may be isogamous, anisogamous or oogamous.
Explanation — Phaeophyceae exhibit different types of sexual reproduction depending on the species, including isogamous, anisogamous and oogamous reproduction.
Isogamous: Dictionary meaning — sexual reproduction in which the two fusing gametes are similar in size and structure.
Explanation — In isogamous reproduction, the male and female gametes are morphologically similar.
Anisogamous: Dictionary meaning — sexual reproduction in which the two fusing gametes differ in size.
Explanation — In anisogamous reproduction, the gametes are unequal in size and generally differ in their characteristics.
Oogamous: Dictionary meaning — sexual reproduction involving a large non-motile female gamete (egg) and a small male gamete.
Explanation — Oogamous reproduction occurs in some members of Phaeophyceae, such as Fucus.
Given Statement - Sexual reproduction in Phaeophyceae may be isogamous, anisogamous or oogamous.
🎯 Conclusion
Sexual reproduction in Phaeophyceae may be isogamous, anisogamous or oogamous, depending on the species.
2
In Phaeophyceae, the union of gametes may take place where?
Practice
A
Only on the surface of the thallus
B
In water or within the oogonium
C
Only inside the antheridium
D
Only in the soil
✅ Show Answer
✔ Correct Answer:
B
(In water or within the oogonium)
💡 Explanation
Union of gametes: Dictionary meaning — the fusion of male and female gametes during sexual reproduction.
Explanation — In Phaeophyceae, the union of gametes may occur in water or within the oogonium, depending on the type of sexual reproduction.
Oogonium: Dictionary meaning — a female reproductive structure in which the egg or eggs are produced.
Explanation — In oogamous species of Phaeophyceae, such as Fucus, fertilisation takes place within the oogonium.
Oogamous species: Dictionary meaning — organisms in which a large non-motile female gamete (egg) fuses with a small male gamete.
Explanation — In oogamous Phaeophyceae, the union of gametes occurs within the oogonium rather than freely in the surrounding water.
Given Statement - In Phaeophyceae, the union of gametes may take place in water or within the oogonium in oogamous species.
Explanation — In Phaeophyceae, the union of gametes may occur in water or within the oogonium, depending on the type of sexual reproduction.
Oogonium: Dictionary meaning — a female reproductive structure in which the egg or eggs are produced.
Explanation — In oogamous species of Phaeophyceae, such as Fucus, fertilisation takes place within the oogonium.
Oogamous species: Dictionary meaning — organisms in which a large non-motile female gamete (egg) fuses with a small male gamete.
Explanation — In oogamous Phaeophyceae, the union of gametes occurs within the oogonium rather than freely in the surrounding water.
Given Statement - In Phaeophyceae, the union of gametes may take place in water or within the oogonium in oogamous species.
🎯 Conclusion
In Phaeophyceae, the union of gametes may occur either in water or within the oogonium, particularly in oogamous species.
3
In Phaeophyceae, the gametes are generally of which shape and bear how many flagella?
Practice
A
Spherical and bear one terminal flagellum
B
Pyriform (pear-shaped) and bear two laterally attached flagella
C
Cylindrical and bear four terminal flagella
D
Rectangular and non-flagellated
✅ Show Answer
✔ Correct Answer:
B
(Pyriform (pear-shaped) and bear two laterally attached flagella)
💡 Explanation
Gametes: Dictionary meaning — reproductive cells that fuse during sexual reproduction to form a zygote.
Explanation — In Phaeophyceae, the gametes are generally pyriform (pear-shaped) and possess two laterally attached flagella.
Pyriform: Dictionary meaning — having the shape of a pear, with one end broader than the other.
Explanation — The gametes of Phaeophyceae are described as pyriform because of their characteristic pear-like shape.
Flagella: Dictionary meaning — slender, whip-like structures that help cells in movement.
Explanation — The gametes bear two laterally attached flagella, which enable them to move through the surrounding water.
Laterally attached flagella: Dictionary meaning — flagella arising from the side of a cell rather than from its end.
Explanation — In Phaeophyceae, the two flagella are attached laterally and help the gametes in locomotion.
Given Statement - The gametes of Phaeophyceae are pyriform (pear-shaped) and bear two laterally attached flagella.
Explanation — In Phaeophyceae, the gametes are generally pyriform (pear-shaped) and possess two laterally attached flagella.
Pyriform: Dictionary meaning — having the shape of a pear, with one end broader than the other.
Explanation — The gametes of Phaeophyceae are described as pyriform because of their characteristic pear-like shape.
Flagella: Dictionary meaning — slender, whip-like structures that help cells in movement.
Explanation — The gametes bear two laterally attached flagella, which enable them to move through the surrounding water.
Laterally attached flagella: Dictionary meaning — flagella arising from the side of a cell rather than from its end.
Explanation — In Phaeophyceae, the two flagella are attached laterally and help the gametes in locomotion.
Given Statement - The gametes of Phaeophyceae are pyriform (pear-shaped) and bear two laterally attached flagella.
🎯 Conclusion
The gametes of Phaeophyceae are pyriform or pear-shaped and bear two laterally attached flagella that help them in movement.
4
Which of the following are common forms of Phaeophyceae (brown algae)?
Practice
A
Chlamydomonas, Volvox, Spirogyra, Ulothrix and Chara
B
Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus
C
Nostoc, Anabaena, Oscillatoria, Chlorella and Scenedesmus
D
Gelidium, Gracilaria, Polysiphonia, Porphyra and Chondrus
✅ Show Answer
✔ Correct Answer:
B
(Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus)
💡 Explanation
Phaeophyceae: Dictionary meaning — a class of algae commonly known as brown algae.
Explanation — The common forms of Phaeophyceae include Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus.
Ectocarpus: Dictionary meaning — a genus of brown algae belonging to Phaeophyceae.
Explanation — Ectocarpus is one of the common forms of Phaeophyceae and is generally found in marine habitats.
Dictyota: Dictionary meaning — a genus of marine brown algae.
Explanation — Dictyota is a common member of Phaeophyceae.
Laminaria: Dictionary meaning — a genus of large marine brown algae, commonly known as kelps.
Explanation — Laminaria is an important common form of Phaeophyceae found in marine environments.
Sargassum: Dictionary meaning — a genus of marine brown algae.
Explanation — Sargassum is a well-known member of Phaeophyceae found in marine habitats.
Fucus: Dictionary meaning — a genus of marine brown algae.
Explanation — Fucus is another common form of Phaeophyceae and is known for oogamous sexual reproduction.
Given Statement - The common forms of Phaeophyceae are Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus.
Explanation — The common forms of Phaeophyceae include Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus.
Ectocarpus: Dictionary meaning — a genus of brown algae belonging to Phaeophyceae.
Explanation — Ectocarpus is one of the common forms of Phaeophyceae and is generally found in marine habitats.
Dictyota: Dictionary meaning — a genus of marine brown algae.
Explanation — Dictyota is a common member of Phaeophyceae.
Laminaria: Dictionary meaning — a genus of large marine brown algae, commonly known as kelps.
Explanation — Laminaria is an important common form of Phaeophyceae found in marine environments.
Sargassum: Dictionary meaning — a genus of marine brown algae.
Explanation — Sargassum is a well-known member of Phaeophyceae found in marine habitats.
Fucus: Dictionary meaning — a genus of marine brown algae.
Explanation — Fucus is another common form of Phaeophyceae and is known for oogamous sexual reproduction.
Given Statement - The common forms of Phaeophyceae are Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus.
🎯 Conclusion
The common forms of Phaeophyceae (brown algae) are Ectocarpus, Dictyota, Laminaria, Sargassum and Fucus.