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Flashcards in Active Transport Deck (11):

Define Active Transport

Active transport is the movement of molecules across a cell membrane against their concentration gradient.


Define Cytosis

Cytosis is a transport mechanism for the movement of large quantities of molecules in and out of cells.


Define Endocytosis

Endocytosis is a form of active transport in which cells absorb large molecules by engulfing them.


Define Phagocytosis

Phagocytosis is a type of endocytosis, by which relatively large particles, such as cell debris and micro organisms, are internalised by the cell.


Define Pinocytosis

Pinocytosis is a type of endocytosis, it is a process which takes in small molecules, including water, from extracellular fluid.


Define Exocytosis

Exocytosis is the exact opposite of endocytosis, by which the intracellular vesicle containing the substance to be expelled fuses with the cell membrane to expel the contents of the vesicle into the extracellular fluid.


What happens during active transport?

During active transport, molecules move from an area of lower concentration to an area of higher concentration.


When is active transport needed?

The process of active transport is required when a cell needs to accumulate high concentrations of molecules such as ions, glucose and animo acids. The process requires cellular energy in the form of chemical energy from ATP or from an electrochemical gradient.


What are the two forms of active transport?

Primary and secondary active transport.


What happens during primary active transport?

During primary active transport, the transmembrane proteins act as pumps which use the chemical energy of ATP.


What happens during secondary active transport?

During secondary active transport, transporter proteins couple the movement of an ion down its electrochemical gradient to the transport of another ion or molecule against its concentration or electrochemical gradient.