The eyespot apparatus (or stigma) is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids .
What are the two main groups of green algae?
Green algae fall into two major groups, the chlorophytes and the charophytes . The chlorophytes include the genera Chlorella, Chlamydomonas, the “sea lettuce” Ulva, and the colonial alga Volvox. The charophytes include desmids, as well as the genera Spirogyra, Coleochaete, and Chara.
Which of the following have an eyespot in their cells?
The eyespot apparatus (or stigma) is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids .
How are red and green algae similar?
Or did they have a common ancestor? Red algae are mostly aquatic and include such familiar organisms as sushi wrap and are the sources of agar and carrageenan. Green algae are terrestrial, and are genetically related to all land plants .
Which algal group contains fucoxanthin pigments and has species that are among the largest algae in the world?
Phylum Phaeophyta (brown algae) – The color of brown algae results from the dominance of the xanthophyll pigment, fucoxanthin, over the Chlorophyll a and c and other pigments. The largest brown algae species are called kelp.
Is euglena a plant or animal?
Euglena, genus of more than 1,000 species of single-celled flagellated (i.e., having a whiplike appendage) microorganisms that feature both plant and animal characteristics . Found worldwide, Euglena live in fresh and brackish water rich in organic matter and can also be found in moist soils.
Do animal cells have eyespots?
They are quite common in small, simple invertebrates, such as Planaria. They do not have lenses or any means of focussing. Therefore, they can sense light from dark, but do not give the animal a visual scene as our eyes do. In many simple animals the eyespot senses light with a pigment molecule called an opsin.
Which green algae is commonest?
Members of the class Chlorophyceae undergo closed mitosis in the most common form of cell division among the green algae, which occurs via a phycoplast. By contrast, charophyte green algae and land plants (embryophytes) undergo open mitosis without centrioles.
What are the similarities between algae and plants?
Plants and algae are both photosynthetic. Both are also considered eukaryotes, consisting of cells with specialized components. They both also have the same life cycle called alternation of generations . However, algae are not plants.
What are the characteristics of a green algae?
The typical green algal cell, which can be motile or nonmotile, has a central vacuole , pigments contained in plastids that vary in shape in different species, and a two-layered cellulose and pectin cell wall. Food is stored as starch in pyrenoids (proteinaceous cores within the plastids).
What are the similarities and differences between green brown and red algae?
The main difference between red brown and green algae is that red algae contain chlorophyll a, chlorophyll d, and phycoerythrin , while brown algae contain chlorophyll a, chlorophyll c, and fucoxanthin and green algae contain chlorophyll a, chlorophyll b, and xanthophylls.
Is red algae edible?
Dulse, (Palmaria palmata), edible red alga (Rhodophyta) found along the rocky northern coasts of the Atlantic and Pacific oceans. Dulse can be eaten fresh or dried . In traditional dishes, it is boiled with milk and rye flour or made into a relish and is commonly served with fish and butter.
Why are algae different colors?
Algae usually are identified with the color green, but they actually occur in a great range of colors and hues, depending on the kind of algae and in some cases on the way they are grown. The colors are due to pigments (colored molecules) within individual cells .
How do humans use red algae?
Red algae form an important part of the ecosystem and are consumed by various organisms such as crustaceans, fish, worms and even humans . Red algae are also used to produce agar that is used as a food additive. They are rich in calcium and also used in vitamin supplements.
Is algae a protist?
algae, singular alga, members of a group of predominantly aquatic photosynthetic organisms of the kingdom Protista . ... Their photosynthetic pigments are more varied than those of plants, and their cells have features not found among plants and animals.
What is unique about algae?
The unique feature of algae is the ability to perform photosynthesis . This is what differentiates them from other organisms and is also the main reason for their inclusion in the plant kingdom. The mode of nutrition is naturally autotrophic mode.
