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ChatGPT
May 28
The nematocyst is a specialized organelle found in the cells of cnidarians, such as jellyfish and sea anemones, that is used for defense and capturing prey. The structure of a nematocyst consists of a capsule containing a coiled, hollow tube with a barbed tip, as well as a trigger mechanism that controls the discharge of the nematocyst.
The mechanism of nematocyst discharge involves a complex process. When the trigger mechanism is activated, the pressure inside the capsule increases, causing the coiled tube to rapidly uncoil and extend outwards. The barbed tip of the tube then penetrates the target, injecting venom or toxins into the prey or predator.
Overall, the structure of the nematocyst and the mechanism of discharge allow cnidarians to effectively capture prey and defend themselves against predators.
The mechanism of nematocyst discharge involves a complex process. When the trigger mechanism is activated, the pressure inside the capsule increases, causing the coiled tube to rapidly uncoil and extend outwards. The barbed tip of the tube then penetrates the target, injecting venom or toxins into the prey or predator.
Overall, the structure of the nematocyst and the mechanism of discharge allow cnidarians to effectively capture prey and defend themselves against predators.
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Google Gemini AI
May 28
Structure of Nematocysts
- Nematocapsule: A spherical or oval structure that houses the coiled tube.
- Operculum: A cap-like structure that closes the opening of the nematocyst.
- Tubule: A long, hollow, and highly elastic thread.
- Thread: A barbed or spiral structure that extends from the tubule.
Mechanism of Nematocyst Discharge
- Trigger: Mechanical or chemical stimuli activate the nematocyst.
- Depolarization: The trigger depolarizes the nematocyte cell, causing calcium influx.
- Osmotic Pressure Rise: Calcium entry increases the osmotic pressure within the nematocyst.
- Tubule Eversion: The increased osmotic pressure causes the tubule to rapidly evert, creating a rapid projectile force.
- Operculum Opening: The operculum is pulled open by the everting tubule.
- Thread Penetration: The barbed or spiral thread extends and penetrates the target, injecting venom or neurotoxins.
Medianism of Nematocyst Discharge
Two main mechanisms for nematocyst discharge have been proposed:
- Hydrostatic Pressure Model: The rapid increase in osmotic pressure within the nematocyte cell exerts hydraulic pressure on the tubule, causing it to evert.
- Vesicle Model: A high concentration of calcium ions triggers the formation of vesicles that rapidly fuse and expel their contents, creating a local osmotic gradient that draws external water into the nematocyst, causing it to expand and evert.
- Nematocapsule: A spherical or oval structure that houses the coiled tube.
- Operculum: A cap-like structure that closes the opening of the nematocyst.
- Tubule: A long, hollow, and highly elastic thread.
- Thread: A barbed or spiral structure that extends from the tubule.
Mechanism of Nematocyst Discharge
- Trigger: Mechanical or chemical stimuli activate the nematocyst.
- Depolarization: The trigger depolarizes the nematocyte cell, causing calcium influx.
- Osmotic Pressure Rise: Calcium entry increases the osmotic pressure within the nematocyst.
- Tubule Eversion: The increased osmotic pressure causes the tubule to rapidly evert, creating a rapid projectile force.
- Operculum Opening: The operculum is pulled open by the everting tubule.
- Thread Penetration: The barbed or spiral thread extends and penetrates the target, injecting venom or neurotoxins.
Medianism of Nematocyst Discharge
Two main mechanisms for nematocyst discharge have been proposed:
- Hydrostatic Pressure Model: The rapid increase in osmotic pressure within the nematocyte cell exerts hydraulic pressure on the tubule, causing it to evert.
- Vesicle Model: A high concentration of calcium ions triggers the formation of vesicles that rapidly fuse and expel their contents, creating a local osmotic gradient that draws external water into the nematocyst, causing it to expand and evert.
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