nostoc Flashcards
What is Nostoc?
Nostoc is the most common genus of Cyanobacteria (blue-green algae), found in both terrestrial and aquatic habitats.
What are some other names for Nostoc?
It is also known as “star jelly” or “spit of the moon.”
What are some other names for Nostoc?
It is also known as “star jelly” or “spit of the moon.”
Why is Nostoc called “star jelly”?
Due to its colonies, which are composed of filaments of moniliform cells within a gelatinous sheath of polysaccharides.
Describe the structure of Nostoc colonies.
They are made up of unbranched filamentous plant bodies, with many filaments aggregated within a gelatinous mass to form a colony.
What type of habitat does Nostoc inhabit?
Nostoc can be found in both terrestrial and aquatic environments.
What is the function of heterocysts in Nostoc?
Heterocysts are specialized cells in Nostoc filaments that aid in nitrogen fixation.
What is a hormogone in Nostoc?
A hormogone is a small fragment of a filament in nostoc that breaks away to form a new colony, aiding in vegetative reproduction.
What role do polysaccharides play in Nostoc colonies?
Polysaccharides form a gelatinous sheath around Nostoc filaments, providing protection and structural support.
What is an akinete, and what is its role in Nostoc?
An akinete is a thick-walled, dormant cell in Nostoc that allows it to survive under unfavorable environmental conditions.
Why is Nostoc important for ecosystems?
Nostoc is a key nitrogen fixer, contributing essential nutrients to both terrestrial and aquatic ecosystems.
How do Nostoc cells perform photosynthesis?
Nostoc cells use pigments like chlorophyll, phycocyanin, and phycoerythrin to capture light energy for photosynthesis.
How do Nostoc cells perform photosynthesis?
Nostoc cells use pigments like chlorophyll, phycocyanin, and phycoerythrin to capture light energy for photosynthesis.
How does Nostoc contribute to soil fertility?
By fixing atmospheric nitrogen, Nostoc enriches the soil with nitrogen, benefiting plant growth.
In what type of environments can Nostoc thrive?
Nostoc can survive in extreme environments, from deserts and arctic regions to nutrient-poor soils and water bodies.
What enables Nostoc to survive in harsh conditions?
The production of akinetes allows Nostoc to endure extreme temperatures and droughts.
What is the primary habitat of Nostoc?
Nostoc is found in both terrestrial and aquatic habitats.
What shape do the cells in Nostoc trichomes typically have?
The cells are rounded or oval, arranged like beads on a string within the trichomes.
What shape do the cells in Nostoc trichomes typically have?
The cells are rounded or oval, arranged like beads on a string within the trichomes.
What shape do the cells in Nostoc trichomes typically have?
The cells are rounded or oval, arranged like beads on a string within the trichomes.
Why is nostoc also known as “star jelly” or “spit of the moon”?
Due to the gelatinous appearance of its colonies.
What pigments are present in Nostoc cells?
Chlorophyll, phycocyanin, and phycoerythrin
Describe the basic structure of a nostoc colony.
Nostoc colony is made up of unbranched filamentous structures within a gelatinous sheath.
How are the cells in Nostoc trichomes arranged?
cells are arranged in a single row, resembling beads on a string.
What are heterocysts, and where are they located?
Heterocysts are nitrogen-fixing cells that are intercalary with two polar nodules.
How does Nostoc reproduce vegetatively?
Through the formation of hormogones and akinetes
How does Nostoc reproduce vegetatively?
Through the formation of hormogones and akinetes
What is the function of heterocysts?
They specialize in nitrogen fixation, converting atmospheric nitrogen into a form usable by the organism.
What color are Nostoc colonies?
Greenish to bluish-green.
What is a trichome in nostoc?
trichome is a chain of cells within the filament, often contorted or twisted.
What is a hormogone?
A fragment of a filament that detaches to form a new colony.
what structural feature distinguishes Nostoc filaments?
The presence of heterocysts within the filament, specialized for nitrogen fixation.
How does Nostoc contribute to aquatic ecosystems?
By fixing nitrogen, Nostoc supports nutrient availability in water bodies.
How does Nostoc respond to nutrient scarcity?
By producing akinetes, which can withstand periods of nutrient scarcity.
What is the arrangement of cells in Nostoc trichomes called?
Moniliform, meaning arranged like beads on a string
Why is Nostoc often found in symbiosis with plants?
It provides nitrogen to plants, forming beneficial partnerships.
What enables Nostoc to survive extreme conditions?
The production of akinetes, which withstand temperature and moisture extremes.
How are new nostoc colonies formed?
Through the release and growth of hormogones.
What is the role of phycoerythrin in nostoc?
Phycoerythrin is a pigment that captures additional light wavelengths for photosynthesis.
What does the pigment phycocyanin do for Nostoc?
It helps absorb specific wavelengths of light, aiding in photosynthesis.
What environmental conditions can Nostoc thrive in?
Nostoc can thrive in diverse conditions, from deserts to nutrient-poor waters.
What is an akinete?
a dormant, thick-walled cell that allows nostoc to survive in harsh conditions.
What structural adaptation helps Nostoc colonies remain intact?
The gelatinous sheath helps colonies adhere together and stay protected.
What structural adaptation helps Nostoc colonies remain intact?
The gelatinous sheath helps colonies adhere together and stay protected.
In what ways is nostoc beneficial for ecosystems?
Nostoc enriches soil fertility, especially in nitrogen-poor environments.
What role does chlorophyll play in nostoc?
Chlorophyll captures light energy for photosynthesis
What role does chlorophyll play in Nostoc?
Chlorophyll captures light energy for photosynthesis.
How does Nostoc contribute to nitrogen availability in soil?
By fixing atmospheric nitrogen, making it available for plant use.
What type of polysaccharides surround Nostoc colonies?
A gelatinous sheath of polysaccharides provides protection and structural support.
How does Nostoc obtain energy?
Through photosynthesis, using chlorophyll and other pigments.
What is the function of polar nodules in heterocysts?
They help in nutrient exchange between heterocysts and vegetative cells in the filament.
How does Nostoc impact its surroundings when in bloom?
It can alter nitrogen levels and create habitat conditions that benefit other organisms.
What gives Nostoc colonies their gelatinous texture?
The secretion of polysaccharides around the filaments.
In what ways can Nostoc colonies change over time?
Colonies can expand as new hormogones form and spread, and they can shrink under stress by producing akinetes.
Why are heterocysts important for nitrogen fixation in nostoc?
They create an anaerobic environment necessary for nitrogenase, the enzyme responsible for nitrogen fixation.
What defensive function does the gelatinous sheath serve?
It protects nostoc cells from desiccation and environmenta
How does the presence of multiple pigments benefit nostoc?
Multiple pigments allow Nostoc to capture a broad range of light wavelengths, optimizing photosynthesis.
What evolutionary advantage does nitrogen fixation provide Nostoc?
It allows nostoc to thrive in nitrogen-poor environments, where many other organisms cannot survive.
What part of Zamia is associated with Nostoc punctiforme?
A: The roots of Zamia.
In which plant does Nostoc punctiforme live as an endophyte within the thallus?
A: Anthoceros.
Name a Nostoc species known to occur as an endophyte in other plants.
A: Nostoc punctiforme.
Approximately how many species are included in the genus Nostoc?
A: About 200 species.
Where do terrestrial species of Nostoc commonly grow?
A: On moist soil intermingled with small plants like liverworts, mosses, and lichens.
Where do terrestrial species of Nostoc commonly grow?
A: On moist soil intermingled with small plants like liverworts, mosses, and lichens.
What type of organism is Nostoc?
A: Nostoc is a genus of cyanobacteria.
In what types of habitats can Nostoc be found?
A: Both terrestrial and aquatic habitats.
What is the relationship between Nostoc punctiforme and its host plants?
It acts as an endophyte, living symbiotically within the host plant tissues.
Which plant’s underground stems harbor Nostoc punctiforme as an endophyte?
Gunnera
Which plant’s underground stems harbor Nostoc punctiforme as an endophyte?
Gunnera
In Cycas, where is Nostoc punctiforme found?
In the coralloid roots of Cycas.
In what kinds of environments does Nostoc particularly thrive?
Nostoc thrives in moist environments and nutrient-poor soils.
Why is Nostoc important ecologically?
It provides nitrogen to the soil, supporting plant growth in nutrient-poor environments.
What is a distinctive feature of Nostoc colonies in aquatic environments?
Nostoc colonies can form visible gelatinous clumps.
In what form does Nostoc appear in aquatic habitats?
It may appear as floating colonies or in filamentous mats.
What symbiotic role does Nostoc often play in its ecosystems?
Nostoc often engages in nitrogen fixation, contributing to soil fertility.
How does Nostoc contribute to its plant hosts, such as in the case of Cycas?
Nostoc provides nitrogen fixation, which benefits the host plant.
In Cycas, where is Nostoc punctiforme found?
In the coralloid roots of Cycas.
In Cycas, where is Nostoc punctiforme found?
In the coralloid roots of Cycas.
