Archaeplastida and Algae Characteristics
Archaeplastida
Common Characteristics:
Photosynthetic organisms featuring a plastid with chlorophyll type "a".
Originates from an ancestral primary endosymbiosis with a cyanobacterium.
Starch is used as a storage product.
Sources: A.Smith et al. Protists
Rhodophyta (Red Algae)
General Features:
Primarily autotrophic and aquatic.
Mostly multicellular organisms, but single-celled species also exist.
Lack flagella at all life cycle stages.
No centrioles present.
Pigments:
Contain chlorophyll a only, along with phycoerythrin, which is a photosynthetic pigment.
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Applications of Red Algae
Cultivation:
Grown on nets in shallow coastal waters.
Products:
Agar
Carrageenan
Dried nori sheets, which are mineral-rich and used as wraps for rice, seafood, and vegetables in sushi.
Green Algae
Taxonomy:
Considered a paraphyletic group.
Cellular Features:
Can be unicellular or multicellular.
Feature a plastid with chlorophyll a and b.
Centrioles are present.
Typically possess a cell wall made of cellulose; however, this is not the case for Chlamydomonas.
Chlamydomonas has a cell wall composed of glycoprotein (carbohydrate-protein).
Examples of Green Algae:
Spirogyra sp.
Ulva sp. (sea lettuce)
Spirogyra
Ploidy Levels:
Haploid (n) and Diploid (2n).
Contains a structure known as a pyrenoid, which is involved in CO$_2$ fixation and is often surrounded by starch.
Chara (Muskgrass)
Classification:
Not a land plant; it is classified as a green alga.
For more information, visit: Chara Species Directory
Chara Life Cycle
Process Overview:
Sperm Formation:
Haploid (n)
Fertilization:
Zygote formation (2n).
Meiosis:
Produces Haploid (n) spores.
Growth:
Zygote develops into a multicellular diploid (2n) organism via germination.
Haploid Cells:
Sperm and spores serve different functions.
Haploid-Diploid Alternation:
Indicated as Zygotic meiosis.