Chlorophyceae - 2
1
How does asexual reproduction take place in green algae?
Practice
A
By fusion of two gametes
B
By fragmentation only
C
By flagellated zoospores produced in zoosporangia
D
By formation of seeds
✅ Show Answer
✔ Correct Answer:
C
(By flagellated zoospores produced in zoosporangia)
💡 Explanation
Asexual reproduction: Dictionary meaning — reproduction in which a new individual is produced from a single parent without the fusion of gametes.
Explanation — In green algae, asexual reproduction occurs without the fusion of male and female gametes. It commonly takes place through the formation of zoospores.
Flagellated: Dictionary meaning — having one or more flagella, which are whip-like structures used for movement.
Explanation — The zoospores have flagella that help them move through water.
Zoospores: Dictionary meaning — motile, usually flagellated asexual spores produced by certain algae and other organisms.
Explanation — Zoospores are asexual reproductive structures. They can move with the help of their flagella and, under suitable conditions, develop into new algal individuals.
Produced: Dictionary meaning — formed or made by an organism or process.
Explanation — The zoospores are formed inside special structures of the algal body before they are released.
Zoosporangia: Dictionary meaning — specialised structures or sacs in which zoospores are formed.
Explanation — Zoosporangia are the structures where the flagellated zoospores develop before being released from the alga.
Given Statement - Asexual reproduction is by flagellated zoospores produced in zoosporangia.
Explanation — In green algae, asexual reproduction occurs without the fusion of male and female gametes. It commonly takes place through the formation of zoospores.
Flagellated: Dictionary meaning — having one or more flagella, which are whip-like structures used for movement.
Explanation — The zoospores have flagella that help them move through water.
Zoospores: Dictionary meaning — motile, usually flagellated asexual spores produced by certain algae and other organisms.
Explanation — Zoospores are asexual reproductive structures. They can move with the help of their flagella and, under suitable conditions, develop into new algal individuals.
Produced: Dictionary meaning — formed or made by an organism or process.
Explanation — The zoospores are formed inside special structures of the algal body before they are released.
Zoosporangia: Dictionary meaning — specialised structures or sacs in which zoospores are formed.
Explanation — Zoosporangia are the structures where the flagellated zoospores develop before being released from the alga.
Given Statement - Asexual reproduction is by flagellated zoospores produced in zoosporangia.
🎯 Conclusion
In green algae, asexual reproduction happens by making tiny moving spores called zoospores. These zoospores are made inside structures called zoosporangia and can grow into new algae.
2
How many types of sexual reproduction are possible in green algae, and what are they?
Practice
A
Two types: isogamous and oogamous
B
Three types: isogamous, anisogamous and oogamous
C
Four types: isogamous, anisogamous, oogamous and vegetative
D
Three types: fragmentation, zoospore formation and oogamous
✅ Show Answer
✔ Correct Answer:
B
(Three types: isogamous, anisogamous and oogamous)
💡 Explanation
Sexual reproduction: Dictionary meaning — reproduction involving the formation and fusion of sex cells or gametes.
Explanation — In green algae, sexual reproduction involves the fusion of sex cells and shows variation in the type and formation of these cells.
Three types: Dictionary meaning — three different forms or categories of a particular process.
Explanation — Sexual reproduction in green algae can occur in three main types based on the nature of the sex cells: isogamous, anisogamous and oogamous.
Isogamous: Dictionary meaning — sexual reproduction involving the fusion of two gametes that are similar in size.
Explanation — In isogamy, the two gametes are similar in size and fuse with each other.
Anisogamous: Dictionary meaning — sexual reproduction involving the fusion of two gametes that are dissimilar in size.
Explanation — In anisogamy, the two gametes are unequal in size and fuse to form a zygote.
Oogamous: Dictionary meaning — sexual reproduction involving the fusion of a large, nonmotile female gamete with a smaller, motile male gamete.
Explanation — In oogamy, the female gamete is large and stationary, while the male gamete is smaller and capable of movement.
Given Statement - The sexual reproduction shows considerable variation in the type and formation of sex cells and it may be isogamous, anisogamous or oogamous.
Explanation — In green algae, sexual reproduction involves the fusion of sex cells and shows variation in the type and formation of these cells.
Three types: Dictionary meaning — three different forms or categories of a particular process.
Explanation — Sexual reproduction in green algae can occur in three main types based on the nature of the sex cells: isogamous, anisogamous and oogamous.
Isogamous: Dictionary meaning — sexual reproduction involving the fusion of two gametes that are similar in size.
Explanation — In isogamy, the two gametes are similar in size and fuse with each other.
Anisogamous: Dictionary meaning — sexual reproduction involving the fusion of two gametes that are dissimilar in size.
Explanation — In anisogamy, the two gametes are unequal in size and fuse to form a zygote.
Oogamous: Dictionary meaning — sexual reproduction involving the fusion of a large, nonmotile female gamete with a smaller, motile male gamete.
Explanation — In oogamy, the female gamete is large and stationary, while the male gamete is smaller and capable of movement.
Given Statement - The sexual reproduction shows considerable variation in the type and formation of sex cells and it may be isogamous, anisogamous or oogamous.
🎯 Conclusion
Sexual reproduction in green algae has three types: isogamous, anisogamous and oogamous. They differ mainly in the size and movement of the sex cells.
3
Which of the following are commonly found green algae?
Practice
A
Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara
B
Laminaria, Sargassum, Fucus, Chara and Volvox
C
Porphyra, Gelidium, Gracilaria, Chlamydomonas and Fucus
D
Eudorina, Laminaria, Sargassum, Gelidium and Chara
✅ Show Answer
✔ Correct Answer:
A
(Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara)
💡 Explanation
Green algae: Dictionary meaning — algae that are generally green in colour because chlorophyll is the dominant photosynthetic pigment.
Explanation — Green algae belong mainly to the class Chlorophyceae and contain chlorophyll a and b as their major pigments.
Chlamydomonas: Dictionary meaning — a genus of unicellular green algae, usually having two flagella for movement.
Explanation — Chlamydomonas is a commonly found unicellular green alga.
Volvox: Dictionary meaning — a genus of colonial green algae that forms spherical colonies of many cells.
Explanation — Volvox is a commonly found colonial green alga in which many cells live together as a colony.
Ulothrix: Dictionary meaning — a genus of filamentous green algae with cells arranged in a thread-like form.
Explanation — Ulothrix is a filamentous green alga commonly found in freshwater habitats.
Spirogyra: Dictionary meaning — a genus of filamentous green algae known for its spiral-shaped chloroplasts.
Explanation — Spirogyra is a common filamentous green alga with distinctive spiral chloroplasts.
Chara: Dictionary meaning — a genus of green algae with a plant-like body and a branched structure.
Explanation — Chara is another commonly found green alga and is often found in freshwater habitats.
Given Statement - Some commonly found green algae are: Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara.
Explanation — Green algae belong mainly to the class Chlorophyceae and contain chlorophyll a and b as their major pigments.
Chlamydomonas: Dictionary meaning — a genus of unicellular green algae, usually having two flagella for movement.
Explanation — Chlamydomonas is a commonly found unicellular green alga.
Volvox: Dictionary meaning — a genus of colonial green algae that forms spherical colonies of many cells.
Explanation — Volvox is a commonly found colonial green alga in which many cells live together as a colony.
Ulothrix: Dictionary meaning — a genus of filamentous green algae with cells arranged in a thread-like form.
Explanation — Ulothrix is a filamentous green alga commonly found in freshwater habitats.
Spirogyra: Dictionary meaning — a genus of filamentous green algae known for its spiral-shaped chloroplasts.
Explanation — Spirogyra is a common filamentous green alga with distinctive spiral chloroplasts.
Chara: Dictionary meaning — a genus of green algae with a plant-like body and a branched structure.
Explanation — Chara is another commonly found green alga and is often found in freshwater habitats.
Given Statement - Some commonly found green algae are: Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara.
🎯 Conclusion
Some common green algae are Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara. They show different body forms, such as single cells, colonies and long threads.