Introduction to Algae in Biology

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Questions and Answers

Which kingdom contains prokaryotic algae?

Fungi

Monera (correct)

Protista

Eukarya

What class is associated with the division Chrysophyta?

Charophyceae

Heterogenerate

Xanthophyceae (correct)

Euglenophyceae

What pigment is found in Rhodophyceae and Cyanophyceae?

Chlorophyll a

Phycocyanin

Phycoerythrin (correct)

Carotenoids

Which of the following amino acid characteristics describes Euglenoids?

Unicellular with two flagella Signup and view all the answers

Which algae have chlorophyll a, b, and carotenoids as pigments?

Euglenophyta Signup and view all the answers

What class belongs to the division Phaeophyta?

Heterogenerate Signup and view all the answers

Which division of algae is classified under the kingdom Protista?

Chlorophyta Signup and view all the answers

What type of algae were previously classified in both plant and animal kingdoms?

Euglenophyta Signup and view all the answers

What is a common characteristic of green algae that links them to plants?

Cell walls made of cellulose Signup and view all the answers

Which of the following is a type of green algae that is unicellular?

Chlamydomonas Signup and view all the answers

What is the primary reserve food material found in Xanthophyceae?

Leucosin Signup and view all the answers

Which substance is NOT commonly derived from marine algae?

Beta-carotene Signup and view all the answers

What distinguishes Vaucheria in terms of its structure?

It has a differentiated thallus structure Signup and view all the answers

What feature is characteristic of the cell wall of Vaucheria?

It consists of two layers with pectic and cellulosic components Signup and view all the answers

What is the ecological role of algae in aquatic ecosystems?

Serve as a primary food source and oxygen producer Signup and view all the answers

Which type of algae is commonly referred to as golden-brown algae?

Chrysophyta Signup and view all the answers

Which feature distinguishes algae from true plants?

Lack of roots, stems, and leaves Signup and view all the answers

What is the primary method by which most algae obtain their energy?

Photosynthesis using sunlight Signup and view all the answers

What type of algae is included in the Chrysophyta group?

Vaucheria Signup and view all the answers

In which habitat can algae be found?

Marine environments Signup and view all the answers

Which of the following statements about algal reproduction is correct?

Algae reproduce both sexually and asexually Signup and view all the answers

Which characteristic is true of freshwater algae?

They are prevalent in moist environments Signup and view all the answers

What do algae primarily lack that differentiates them from vascular plants?

True embryos and vascular systems Signup and view all the answers

Which of the following is NOT a type of attachment for algae?

Photosynthetic Signup and view all the answers

Which pigments are found in dinoflagellates?

Chlorophyll a, c, Carotenes, Fucoxanthin Signup and view all the answers

What characteristic is NOT true for chirosiphonous algae?

They possess locomotory organs. Signup and view all the answers

Which algae is noted for being non-motile and primarily attached to rocks?

Rhodophyta Signup and view all the answers

Which of the following algae is known for forming toxic red tides?

Dinoflagellates Signup and view all the answers

What is the primary function of diatoms in aquatic ecosystems?

Serving as a food source Signup and view all the answers

Which type of algal cell wall consists of two overlapping shells made of silica?

Chrysophyta Signup and view all the answers

Which group of algae is primarily characterized by a differentiated structure such as blades and holdfasts?

Phaeophyta Signup and view all the answers

Which pigments are NOT found in brown algae?

Chlorophyll b Signup and view all the answers

Study Notes

Introduction to Phycology (Algae)

Algae are photosynthetic organisms
They carry out 50-60% of Earth's photosynthesis
They use sunlight and chlorophyll to create food
Range from microscopic single-celled organisms to large seaweed
Most are aquatic, found in oceans, freshwater, ponds, lakes, streams, hot springs, polar ice, moist soil, trees, and rocks.
Algae are non-vascular, primitive plants lacking roots, stems, and leaves.
They reproduce both sexually and asexually using spores, rather than seeds.

Eukaryotes - Algae

Euglenophyta
Dinoflagellates
Chrysophyta (EX. Vaucheria sp)
Rhodophyta (Red Algae)
Phaeophyta (Brown Algae)
Chlorophyta (Green Algae; EX: Chlamydomona + Volvox sp. + Spirogyra sp)
Importance of Algae

Kingdom: Protista or Algae

Algae are divided into prokaryotic (cyanobacteria) and eukaryotic organisms
Algae are photosynthetic.

Algal Classification

Algae are classified based on pigment composition.
Algae are classified into two kingdoms: Monera (prokaryotic algae: Cyanophyta (blue-green algae)) and Protista (eukaryotic algae). There are 6 divisions

4- Algal Pigments

All algae contain photosynthetic pigments (chlorophyll a, b, c, d, e, f – 6 types).
Carotenoids and Xanthophylls are yellow, red, or orange pigments.
Phycobilins (phycocyanin – blue pigment; phycoerythrin – pink-red pigment) are present in Rhodophyceae and Cyanophyceae.

1- Euglenophyta

Earlier, Euglenoids were classified with both plants and animals (protozoa).
Molecular data shows Euglenoids are closely related to Zooflagellates.
Euglenoids are unicellular with two flagella (one long, one short).
They are plant-like in their pigments (chlorophyll a, b, and carotenoids).
Some photosynthetic Euglenoids lose chlorophyll in the dark and become heterotrophic (ingesting organic matter).
Other Euglenoids are always colorless and heterotrophic.
Example: Euglena (evolutionary significance)

2- Dinoflagellates

Unusual protists with different structures and two dissimilar flagella.
Cells are often covered with interlocking cellulose plates or silicates.
Pigments include chlorophyll a, c, carotenoids, and fucoxanthin.
Ecologically important in marine ecosystems, producing oxygen.
Can cause blooms (population explosions) that color water orange, red, or brown (toxic red tides).
Examples: Gonyaulax, Ceratium

3- Chrysophyta (Golden Algae – Diatoms)

Mostly unicellular; lack locomotory organs.
Pigments: chlorophyll a, c, carotenoids, xanthophylls.
Cell wall of two overlapping shells, resembling a petri dish, made of silica.
Important in aquatic food chains.
Examples: Diatom, Frequilaria, Pinnularia

4- Phaeophyta (Brown Algae)

Multicellular; range from a few centimeters to 75 meters long.
Largest are called kelps.
Kelps have tough, leathery leaf-like blades, stem-like stipes, and root-like holdfasts.
Non-motile; reproductive cells with two flagella.
Pigments: Chlorophyll a, c, carotenoids, and fucoxanthin.
Common in cooler marine water, especially along coastlines (intertidal zone).
Examples: Fucus, Macrocystis

5- Rhodophyta (Red Algae)

Multicellular; complex interwoven filaments.
Filaments are delicate and feathery, or some form flattened sheets.
Non-motile.
Most multicellular species are attached to rocks or other substrates by a basal holdfast.
Pigments: Chlorophyll a, carotenoids, and phycoerythrin (red pigment).
Some incorporate calcium carbonate into their cell walls.

6- Chlorophyta (Green Algae)

Unicellular, colonial, or multicellular.
Pigments: chlorophyll a, b, and carotenoids.
Most have flagella.
Cell walls are made of cellulose.
Similar characteristics to plants (pigments, products, and cell walls).
A branch of the monophyletic plant lineage.
Examples: Chlamydomonas (unicellular), Volvox (colonial), Spirogyra (filamentous), Ulva (sheet-like multicellular).

Importance of Algae

Some algae (e.g., kelps) are edible; food source.
Source of useful substances (algin, agar, carrageenan, fucoidan, carotenoids).
Essential in aquatic ecosystems, forming the base of food chains, providing food and oxygen.
Used in various products (cosmetics, pharmaceuticals, food production).

Vaucheria sp.

Thallus is a single-branched tubular filament; multinucleate coenocytic.
Contains a large central vacuole; cell wall is thin, weak, and non-elastic, made of pectic and cellulosic layers.
Attached to the substratum by colorless rhizoids or holdfasts.
Reproductive structures appear as septa.
Found in freshwater.

Additional notes

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Description

Explore the fascinating world of algae, the photosynthetic organisms responsible for a significant portion of Earth's oxygen production. This quiz covers the classification, types, and importance of algae in various ecosystems, providing insight into their role as both prokaryotic and eukaryotic organisms. Test your knowledge on their characteristics, reproduction, and ecological significance.