Phaeophyceae (Brown Algae)
Details the features, pigments (chlorophyll a, c, fucoxanthin), stored food (laminarin, mannitol), cell wall, thallus structure, and examples of brown algae.
What is Phaeophyceae (Brown Algae)?
The undifferentiated vegetative body of algae, fungi, and some other lower plants, lacking true roots, stems, and leaves.
Key points
- Identify the characteristic features of Phaeophyceae.
- Describe the pigments and stored food in brown algae.
- Explain the thallus structure and its components.
- List common examples of brown algae and their habitats.
Common exam trap
Confusing the pigments of brown algae with other algal groups.
Definitions
- Term
Thallus
- Meaning
The undifferentiated vegetative body of algae, fungi, and some other lower plants, lacking true roots, stems, and leaves.
- Term
Fucoxanthin
- Meaning
A prominent carotenoid pigment found in brown algae (Phaeophyceae) and diatoms, responsible for their characteristic brown or golden-brown colour.
- Term
Algin
- Meaning
A gelatinous polysaccharide extracted from the cell walls of brown algae, used commercially as a thickening and stabilizing agent.
- Term
Pneumatocysts
- Meaning
Gas-filled bladders or floats found in some brown algae, which provide buoyancy and help keep the photosynthetic parts near the surface of the water.
Learning objectives
Identify the characteristic features of Phaeophyceae.
Describe the pigments and stored food in brown algae.
Explain the thallus structure and its components.
List common examples of brown algae and their habitats.
Understand the reproductive strategies employed by brown algae.
Prerequisites
Basic understanding of plant cell structure.
Knowledge of photosynthesis and pigments.
Familiarity with different modes of reproduction (vegetative, asexual, sexual).
Common mistakes
Confusing the pigments of brown algae with other algal groups.
Incorrectly identifying the stored food materials.
Overlooking the presence of algin in the cell wall.
Assuming all algae are microscopic or freshwater.
Keywords
Phaeophyceae
Brown Algae
Fucoxanthin
Laminarin
Mannitol
Algin
Thallus
Holdfast
Stipe
Lamina
Pneumatocysts
Marine Algae
Kelp
Practice preview
The thallus of brown algae is typically differentiated into holdfast, stipe, and blade. This level of organization is described as:…
medium
Which of the following statements about Phaeophyceae is INCORRECT?…
medium
The primary photosynthetic pigments in Phaeophyceae are:…
easy