gas vesicle

Examples of gas vesicle in the following topics:

• Gas Vesicles

  • There is a simple relationship between the diameter of the gas vesicle and pressure at which it will collapse - the wider the gas vesicle the weaker it becomes.
  • However, wider gas vesicles are more efficient.
  • They provide more buoyancy per unit of protein than narrow gas vesicles.
  • This will select for species with narrower, stronger gas vesicles.
  • Discuss the role of a gas vesicle in regards to survival

• Cyanobacteria

  • Heterocyst-forming species are specialized for nitrogen fixation and are able to bind nitrogen gas to ammonia (NH3), nitrites (NO−2) or nitrates (NO−3).
  • In water columns some cyanobacteria float by forming gas vesicles, like in archaea.
  • These vesicles are not organelles as such.

• Vesicles and Vacuoles

  • Vesicles and vacuoles are membrane-bound sacs that function in storage and transport.
  • Vesicles can fuse with the plasma membrane to release their contents outside the cell.
  • Vesicles can also fuse with other organelles within the cell.
  • Vesicles perform a variety of functions.
  • Vesicles are involved in metabolism, transport, buoyancy control, and enzyme storage.

• Exocytosis

  • The first stage is called vesicle trafficking.
  • The next stage that occurs is vesicle tethering, which links the vesicle to the cell membrane by biological material at half the diameter of a vesicle.
  • Next, the vesicle's membrane and the cell membrane connect and are held together in the vesicle docking step.
  • The final stage, vesicle fusion, involves the merging of the vesicle membrane with the target membrane.
  • In exocytosis, vesicles containing substances fuse with the plasma membrane.

• Excitation–Contraction Coupling

  • The deadly nerve gas Sarin irreversibly inhibits acetycholinesterase.
  • The Ca2+ ions allow synaptic vesicles to move to and bind with the presynaptic membrane (on the neuron) and release neurotransmitter from the vesicles into the synaptic cleft.

• Development of Vision

  • First, an outpocketing of the neural tube occurs, creating optic vesicles.
  • The optic vesicles come into contact with the epithelium and induce the epidermis.
  • Further induction by the chordamesoderm forms a protrusion: the optic vesicle.
  • Some cells in the lens vesicle will form the cornea and the lens vesicle will develop completely to form the definitive lens.
  • After the closure of the tube they are known as the optic vesicles.

• The Golgi Apparatus

  • We have already mentioned that vesicles can bud from the ER and transport their contents elsewhere, but where do the vesicles go?
  • The transport vesicles that formed from the ER travel to the cis face, fuse with it, and empty their contents into the lumen of the Golgi apparatus.
  • Finally, the modified and tagged proteins are packaged into secretory vesicles that bud from the trans face of the Golgi.
  • While some of these vesicles deposit their contents into other parts of the cell where they will be used, other secretory vesicles fuse with the plasma membrane and release their contents outside the cell.
  • Several vesicles can be seen near the Golgi apparatus.

• Nitrogen Fixation: Root and Bacteria Interactions

  • Therefore, using rhizobia is a natural and environmentally-friendly way to fertilize plants as opposed to chemical fertilization that uses a non-renewable resource, such as natural gas.
  • The bacteria are encased in (b) vesicles inside the cell, as can be seen in this transmission electron micrograph.

• Transcytosis

  • Transcytosis, or vesicle transport, is one of three mechanisms that facilitate capillary exchange, along with diffusion and bulk flow.
  • Substances are transported through the endothelial cells themselves within vesicles.
  • The substance to be transported is endocytosed by the endothelial cell into a lipid vesicle which moves through the cell and is then exocytosed to the other side.
  • Vesicles are capable of merging, allowing for their contents to mix, and can be transported directly to specific organs or tissues.

• Equations of State

  • The ideal gas law is the equation of state of a hypothetical ideal gas (in which there is no molecule to molecule interaction).
  • The ideal gas law is the equation of state of a hypothetical ideal gas (an illustration is offered in ).
  • while Charles' law states that volume of a gas is proportional to the absolute temperature T of the gas at constant pressure
  • The proportionality factor is the universal gas constant, R, i.e.
  • Therefore, we derive a microscopic version of the ideal gas law