Algae
Chlorophyceae, Phaeophyceae and Rhodophyceae — pigments, stored food and reproduction. (Biology › Plant Kingdom, NEET UG syllabus.)
What is Algae?
A plant body not differentiated into true roots, stems, and leaves.
Key points
- Differentiate between Chlorophyceae, Phaeophyceae, and Rhodophyceae based on their characteristic features.
- Identify the dominant pigments and stored food materials for each class of algae.
- Describe the cell wall composition and flagellation patterns in green, brown, and red algae.
- Explain the modes of reproduction observed in each algal class.
Common exam trap
Confusing the dominant pigments (e.g., fucoxanthin vs. phycoerythrin) between brown and red algae.
Definitions
- Term
Thallus
- Meaning
A plant body not differentiated into true roots, stems, and leaves.
- Term
Isogamy
- Meaning
Sexual reproduction involving the fusion of two gametes that are similar in size and morphology.
- Term
Anisogamy
- Meaning
Sexual reproduction involving the fusion of two gametes that are dissimilar in size.
- Term
Oogamy
- Meaning
Sexual reproduction involving the fusion of a large, non-motile female gamete and a smaller, motile male gamete.
- Term
Hydrocolloids
- Meaning
Water-holding substances, often polysaccharides, like algin and carrageenan, used as thickeners or gelling agents.
- Term
Fucoxanthin
- Meaning
The dominant brown pigment found in Phaeophyceae (brown algae).
- Term
Phycoerythrin
- Meaning
The dominant red pigment found in Rhodophyceae (red algae).
- Term
Floridean Starch
- Meaning
The stored food material in red algae, structurally similar to amylopectin and glycogen.
Learning objectives
Differentiate between Chlorophyceae, Phaeophyceae, and Rhodophyceae based on their characteristic features.
Identify the dominant pigments and stored food materials for each class of algae.
Describe the cell wall composition and flagellation patterns in green, brown, and red algae.
Explain the modes of reproduction observed in each algal class.
Provide relevant examples of algae belonging to each of the three major classes.
Prerequisites
Basic understanding of plant characteristics and classification.
Knowledge of photosynthetic pigments and their role.
Familiarity with different modes of reproduction (vegetative, asexual, sexual).
Common mistakes
Confusing the dominant pigments (e.g., fucoxanthin vs. phycoerythrin) between brown and red algae.
Mixing up the types of stored food (starch, laminarin/mannitol, floridean starch) for each class.
Incorrectly identifying the number, equality, and position of flagella for each class.
Forgetting that Rhodophyceae completely lack flagella.
Not recalling the specific components of the cell wall for each algal class.
Keywords
Algae
Chlorophyceae
Phaeophyceae
Rhodophyceae
Pigments
Stored food
Cell wall
Flagella
Reproduction
Fucoxanthin
Phycoerythrin
Floridean starch
Agar
Algin
Carrageenan
Kelps
Thallus
Practice preview
The stored food in Rhodophyceae is structurally very similar to which of the following?…
easy
Match the following algal classes with their characteristic features: Column I (Algal Class) A. Chlorophyceae B. Phaeophyceae C. Rhodophyceae Column II (Characteristic Feature) 1. Floridean starch 2. Pyrenoids 3. Fucox…
medium
Which of the following combinations correctly represents the stored food and cell wall composition for a specific class of algae?…
hard