Structure of algae:
- Algae are photosynthetic organisms that can range from single-celled to multicellular forms.
- They play an important role as primary producers in aquatic ecosystems.
- The structure of algae can vary depending on factors such as their habitat and size etc.
| Structural Feature | Characteristics | Function |
| Pyrenoids
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· Pyrenoid, a dense structure inside certain algae, containing starch granules.
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· Pyrenoids store starch as energy reserve that can be mobilized as needed for metabolic processes.
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| Thallus
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· Body of algae is called thallus.
· It can range from simple unicellular forms to complex multicellular structures. |
· The thallus houses specialized structures that perform various functions such as photosynthesis, reproduction and anchoring. |
| Flagella |
· Flagella are whip-like appendages that extend from the cell surface. |
· Flagella are involved in movement, helping algae in swimming towards or away from source of stimuli such as light and nutrients. |
| Blades
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· Blades are leaf-like structures found in many algae. · They are flat, broad, and often photosynthetic. |
· Blades maximize the surface area exposed to sunlight thus enabling the algae in efficient photosynthesis. |
| Stipes
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· Stipes are stem-like structures that provide support for blades and other parts of the algal body. |
· Stipes serves as channels for the transport of nutrients and other essential substances.
· They also facilitate exposure to sunlight. |
| Holdfasts
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· Holdfasts are anchor-like structures that attach algae to substrates such as rocks, other algae, or the ocean floor. |
· They prevent the algae from drifting away and aid in stabilizing the thallus.
· They help stabilize the thallus and maintain its position for optimal light exposure and nutrient uptake. |
| Air Bladders |
· These are gas-filled structures that increase the buoyancy of certain algae. |
· Air bladders increase the buoyancy of algae, allowing them to float at specific depths in water. |
| Chloroplasts
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· Chloroplasts contain pigments known as chlorophyll, which capture sunlight for photosynthesis. |
· Chloroplasts facilities in photosynthesis. · Chloroplast converts light energy into chemical energy. |
| Cell Wall
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· The cell wall surrounds the cell membrane in the algal cell.
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· The cell wall offers protection against mechanical stress and osmotic changes. · It maintains the structural integrity of the cell and helps to retain its shape. |
| Pseudopodia |
· Pseudopodia are temporary projections of the cell body, often found in unicellular algae. |
· With the help of pseudopodia, algae can move and engulf prey or organic matter. |
| Eyespots
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· Eyespots, also known as stigma, are light-sensitive structures found in some algae.
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· With the help of eyespots, algae can orient themselves for optimal photosynthesis or movement towards light sources. |
| Nucleus
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· The nucleus is the control center of the cell.
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· The nucleus contain DNA that directs cell activities, including growth, metabolism, and reproduction. |
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Cytoplasm |
· The cytoplasm is the gel-like substance within the cell. |
· It houses organelles and provides the environment for chemical reactions. |
| Vacuoles |
· Vacuoles are fluid-filled sacs that store water, nutrients, and waste products. |
· They maintain turgor pressure, regulate osmotic balance, and serve as reservoirs for essential molecules. |
| Phycobilins
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· These are red and blue pigments, found in certain algae
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· Phycobilins absorb light in the blue and red regions of the spectrum, where chlorophyll has lower absorption. |
| Xanthophylls | · Yellow pigments, often found with the chlorophyll. | · Xanthophylls absorb and quench excess light energy, thus reducing the potential damage to cellular structures. |
| Carotenoids
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· Orange and red pigments, found in some algae
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· Similar to xanthophylls, carotenoids are involved in dissipating excess light energy as heat.
· Carotenoids act as antioxidants, scavenging harmful free radicals produced during photosynthesis. |