Questions and Answers
What are the shapes of red algae?
Where are red algae found?
All latitudes, occupying huge ranges of depth, up to 268m.
What are corallines important for?
Formation of tropical reefs.
What habitats do red algae occupy?
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Epiphytes are found on _____ , and epizoic are found on _____ , while epilithic are found on _____ , and psammophilic are found in _____ .
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What are red algae mostly used for?
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What do red algae produce that is useful for pharmaceutical research?
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What do red algae have between their cells?
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What do red algae cell walls include?
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The extracellular matrix is dominated by what?
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How many stages are red algae life cycles divided into?
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Where do red algae reserve food and in what form?
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What is Agar?
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What is carrageenan?
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Describe Rhodophyta's way of collecting sunlight.
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What two pigments affect the color of red algae?
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What is the structure of the chloroplast in red algae?
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What is a fundamental characteristic of multicellular red algae?
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Cells in filaments are linked by ______ and cells from different lines can become connected. Location in the filament can affect the ______ and ______ properties.
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How do males fertilize female eggs in red algae?
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After a carposporophyte forms, what happens next?
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What does isomorphic mean in the context of red algae?
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What does heteromorphic mean?
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What is a systocarp?
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What is the morphological approach to taxonomy in red algae?
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Study Notes
Shapes of Red Algae
- Common shapes include cylindrical, bead-like, blade-like, filaments, proliferations, and thalli.
Distribution
- Found in all latitudes, red algae inhabit various depths, with some species recorded at depths of up to 268 meters.
Ecological Importance
- Coralline red algae play a crucial role in the formation of tropical reefs.
Habitat Diversity
- Approximately 14,000 described species exist; 3% are found in freshwater ecosystems.
Types of Algal Habitats
- Epiphytes grow on other algae, seagrasses, and roots.
- Epizooic species live on animals.
- Epilithic algae inhabit pebbles and rocks.
- Psammophilic algae thrive in sandy environments.
Culinary Significance
- Red algae are a vital food source for many Asian cultures, noted for their ability to metabolize polyunsaturated fatty acids.
Research Applications
- They produce oxylipins, which are significant for pharmaceutical research.
Cellular Connections
- Red algae feature pit connections that link cells together.
Cell Wall Composition
- The cell walls are made from rigid microfibrils embedded in a mucilaginous matrix, containing phycocolloids.
Extracellular Matrix
- Dominated by hydrophilic polymers such as agar and carrageenan.
Life Cycle Stages
- The life cycle of red algae comprises three distinct stages.
Nutritional Reserves
- Food reserves are stored outside chloroplasts as Floridean starch.
Agar Definition
- Agar serves as a nutrient medium for growing bacteria and fungi, and finds use in the food and drug industries.
Carrageenan Use
- Functions as a gelatin substitute, widely utilized in food products in Japan and the Philippines.
Photosynthesis Mechanism
- Contain chlorophyll a and phycoerythrin, allowing efficient light absorption, especially blue and green wavelengths.
Color Variation
- Color is influenced by the ratio of phycoerythrin to phycocyanin, affecting the overall hue.
Chloroplast Structure
- Chloroplasts possess a double membrane and consist of single thylakoids.
Multicellular Structure
- Multicellular red algae are characterized by branched filamentous structures.
Cell Connectivity
- Filament cells are interconnected by pit plugs; cells of different lineages have specific connections.
Fertilization Process
- Male gametes are carried by ocean currents to the female's carpogonium tip (trichogyne), leading to the formation of a diploid carposporophyte.
Development Following Fertilization
- The carposporophyte gives rise to carpospores, which develop into a tetrasporophyte through meiosis.
Isomorphic Phase
- In isomorphic life cycles, gametophyte and tetrasporophyte stages appear morphologically similar.
Heteromorphic Phase
- In heteromorphic life cycles, gametophytes alternate with smaller, free-living tetrasporophytes.
Systocarp Definition
- A systocarp is the fruiting body created post-fertilization, essential for classification in red algae.
Taxonomy Approach
- Morphological taxonomy involves comparing similarities during various developmental stages, though developmental differences may exist.
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Test your knowledge of red algae with these flashcards. Learn about their shapes, habitats, and ecological significance. Ideal for students or anyone interested in marine biology.
