vesicular transport lecture Flashcards
define vesicular transport
a means by which substances are actively transported in/out of the cell, and involves the use of ATP
what is transported in vesicular transport?
it generally involves the transport of large macromolecules that are too big to be transported across the plasma membrane via channels/carrier proteins
what is endocytosis
it involves the movement of substances into the cell eg. the engulfment of bacteria by neutrophils it involves the invagination/infolding of a portion of the plasma membrane
what is exocytosis
the movement of substances out of the cell eg. release of digestive enzymes by the pancreas. essentially the functional opposite of endocytosis
phagocytosis
involves the movement of large particles into the cell - often referred to as cell eating and involves the capture and internalization of large particles - performed by special cells known as phagocytes.
examples of phagocytes
eg. of phagocytes include white blood cells , neutrophils and macrophages
what is a lysosome
cellular vesicles that contain digestive enzymes
what is the first step to phagocytosis
- binding of the target to the plasma membrane of the phagocyte cell, triggering a deformation of the plasma membrane and the formation of cytoplasmic extensions (pseudopodia)
what is the second step to phagocytosis
when the lysosome fuses with the phagosome, digestive enzymes are mixed with the bacteria or the cells or the particles digests/neutralises it
what is pinocytosis
often referred to as cell drinking. it is the engulfment of dropletsof extracellular fluid into the cell via tiny vesicles
what performs pinocytosis
it is performed by cells lining the small intestine to absorb small fat droplets and is also believed to be involved in immune surveillance
what is receptor mediated endocytosis
allows the cell to acquire and bring in specific substances- mediated by receptors on the plasma membrane
