Podcast
Questions and Answers
What is the main difference between the cyanelles of Cyanophora paradoxa and regular plastids found in higher plants?
What is the main difference between the cyanelles of Cyanophora paradoxa and regular plastids found in higher plants?
- Production of photosynthetic enzyme (correct)
- Type of starch stored
- Location of the nucleus
- Presence of flagellated cells
Where are the cyanelles of Cyanophora paradoxa thought to be similar in evolution to?
Where are the cyanelles of Cyanophora paradoxa thought to be similar in evolution to?
- Chloroplasts (correct)
- Glaucocystis
- Cyanobacteria
- Red algae
What is the unique characteristic of the ecological niche that the first red alga likely evolved into?
What is the unique characteristic of the ecological niche that the first red alga likely evolved into?
- Low oxygen levels
- High temperature
- Low pH (correct)
- High salinity
What is the main difference between the Rhodophyceae and other algal classes?
What is the main difference between the Rhodophyceae and other algal classes?
What is the characteristic of the thylakoids in the chloroplasts of Rhodophyceae?
What is the characteristic of the thylakoids in the chloroplasts of Rhodophyceae?
Who first proposed the endosymbiotic origin of chloroplasts?
Who first proposed the endosymbiotic origin of chloroplasts?
What is the main characteristic of the larger species of fleshy red algae?
What is the main characteristic of the larger species of fleshy red algae?
What did Mereschkowsky liken plastids to in his theory?
What did Mereschkowsky liken plastids to in his theory?
What has reinforced Mereschkowsky's theory of endosymbiotic origin of plastids?
What has reinforced Mereschkowsky's theory of endosymbiotic origin of plastids?
What is the approximate number of species of Rhodophyceae?
What is the approximate number of species of Rhodophyceae?
What has shown the similarity between cyanobacteria and plastids?
What has shown the similarity between cyanobacteria and plastids?
What is the characteristic of the Rhodophyceae that allows them to live at greater depths in the ocean?
What is the characteristic of the Rhodophyceae that allows them to live at greater depths in the ocean?
What is thought to represent intermediates in the evolution of the chloroplast?
What is thought to represent intermediates in the evolution of the chloroplast?
What was the likely outcome of the mutation that allowed the cyanobacterium to survive in the host flagellate?
What was the likely outcome of the mutation that allowed the cyanobacterium to survive in the host flagellate?
What is unique about the symbiotic association in Glaucophyta?
What is unique about the symbiotic association in Glaucophyta?
What is the likely reason for the cyanobacterium's increased secretion of metabolites to the host flagellate?
What is the likely reason for the cyanobacterium's increased secretion of metabolites to the host flagellate?
Where does the fusion of one male nucleus and the carpogonial nucleus occur?
Where does the fusion of one male nucleus and the carpogonial nucleus occur?
What is the result of fertilization in the carpogonial branch?
What is the result of fertilization in the carpogonial branch?
What is the function of the trichogyne in the reproductive process of red algae?
What is the function of the trichogyne in the reproductive process of red algae?
What is the characteristic of the cell wall in the carpogonium after fertilization?
What is the characteristic of the cell wall in the carpogonium after fertilization?
What is the arrangement of tetraspores in a tetrasporangium?
What is the arrangement of tetraspores in a tetrasporangium?
What is the function of dictyosomes in the formation of tetraspores?
What is the function of dictyosomes in the formation of tetraspores?
What is the characteristic of spores in red algae?
What is the characteristic of spores in red algae?
How many classes are there in the Rhodophyta?
How many classes are there in the Rhodophyta?
What is the main difference between carrageenan and agar?
What is the main difference between carrageenan and agar?
What is the role of potassium ions in the formation of carrageenan gels?
What is the role of potassium ions in the formation of carrageenan gels?
What is the main use of carrageenans in the dairy industry?
What is the main use of carrageenans in the dairy industry?
What is the advantage of carrageenans in instant puddings, sauces, and creams?
What is the advantage of carrageenans in instant puddings, sauces, and creams?
What is the function of spermatia in the sexual reproduction of red algae?
What is the function of spermatia in the sexual reproduction of red algae?
What is the difference between carpospores and tetraspores?
What is the difference between carpospores and tetraspores?
What is the function of gonimoblast filaments in the sexual reproduction of red algae?
What is the function of gonimoblast filaments in the sexual reproduction of red algae?
What is a property of carrageenans that makes them useful in pharmaceutical applications?
What is a property of carrageenans that makes them useful in pharmaceutical applications?
What is the characteristic of the thalli of Red Algae in intertidal or shallow subtidal environments?
What is the characteristic of the thalli of Red Algae in intertidal or shallow subtidal environments?
Which pigments are responsible for the red coloration of Red Algae?
Which pigments are responsible for the red coloration of Red Algae?
What is the characteristic of the morphology of Red Algae in Order Batrachospermales?
What is the characteristic of the morphology of Red Algae in Order Batrachospermales?
Where are Red Algae in Order Nemaliales typically found?
Where are Red Algae in Order Nemaliales typically found?
What is the characteristic of the thalli of Red Algae in Order Corallinales?
What is the characteristic of the thalli of Red Algae in Order Corallinales?
What is the characteristic of the reproduction of Red Algae?
What is the characteristic of the reproduction of Red Algae?
What is the characteristic of the color of Red Algae in Order Corallinales?
What is the characteristic of the color of Red Algae in Order Corallinales?
Where are Red Algae in Order Corallinales typically attached to?
Where are Red Algae in Order Corallinales typically attached to?
Study Notes
Endosymbiotic Origin of Chloroplasts
- Konstantin Mereschkowsky proposed the endosymbiotic origin of chloroplasts in 1905.
- He likened plastids to "little green slaves" working for their host cells to produce food from sunshine.
- Nucleotide sequencing has shown the similarity between cyanobacteria and plastids, supporting the endosymbiotic origin theory.
- All plastids evolved from a single endosymbiotic event.
Evolution of Chloroplasts
- A cyanobacterium was taken up by a phagocytic organism into a food vesicle, leading to an endosymbiotic relationship.
- The cyanobacterium evolved into a chloroplast surrounded by two membranes of the chloroplast envelope.
Glaucophyta
- Glaucophyta includes algae that have endosymbiotic cyanobacteria in their cytoplasm instead of chloroplasts.
- They are thought to represent intermediates in the evolution of chloroplasts.
- The cyanelles of Cyanophora paradoxa are similar to chloroplasts in evolution, but are primitive in regard to where photosynthetic enzymes are produced.
Rhodophyta
- Rhodophyta is a division of red algae that comprises the class Rhodophyceae.
- Rhodophyceae are probably one of the oldest groups of eukaryotic algae.
- They are directly descended from a cyanome in the Glaucophyta.
- The first red alga likely evolved into an ecological niche unoccupied by cyanobacteria, in waters with a pH less than 5.
Characteristics of Rhodophyceae
- Lack flagellated cells
- Have chlorophyll a, phycobiliproteins, Floridian starch as a storage product, and thylakoids occurring singly in the chloroplast
- Most species are found in marine environments, particularly in intertidal zones
- Reproduce sexually and asexually by spores or filament fragmentation
Carrageenan
- Carrageenan is a phycocolloid similar to agar but with a higher ash content and requiring higher concentrations to form gels.
- It is obtained from wild populations of Irish moss and is used extensively for many purposes, including stabilizing emulsions and stiffening milk and dairy products.
Red Algae Reproduction
- In sexual reproduction, gamete cells have no flagella and spermatia are carried passively by water currents to the female organ, the carpogonium.
- Fertilization stimulates the production of polyamine spermine, which steers the carpogonial branch toward the production of carpospores.
- Tetrasporangia form four tetra spores, either in a row, crosswise, or in a tetrad.
Asexual Spores
- Monosporangia and parasporangia produce asexual spores that re-form the parent thallus.
- Spores, whether monospores, tetraspores, or carpospores, of almost all red algae are capable of motility by gliding.
Red Algae Classification
- Rhodophyta has a single class, the Rhodophyceae.
- The Rhodophyceae was previously divided into two subclasses, the Bangiophycidae and the Florideophycidae.
- There are several orders of red algae, including Batrachospermales, Nemaliales, and Corallinales, each with distinct characteristics.
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Description
Learn about the endosymbiotic origin of chloroplasts, first proposed by Konstantin Mereschkowsky. Discover how plastids work with host cells to produce food from sunlight.