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Definition
transport of a substance across a cell membrane by diffusion, uses gradient energy
transports with gradient(cannot use to concentrate nutrients) |
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Term
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Definition
The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy
uses PMF or ATP for energy |
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Term
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Definition
| also called direct active transport, directly uses energy to transport molecules across a membrane |
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Term
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Definition
transporters use ATP in addition to a signal from a periplasmic binding protein to open a transport channel and import a solute.
provides a cap that prevents backflow |
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Term
Secondary active transport |
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Definition
| In secondary active transport, in contrast to primary active transport, there is no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of the cell is used |
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Term
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Definition
are single-polypeptide secondary carriers capable only of transporting small solutes in response to chemiosmotic ion gradients
proteins use energy from gradient of one ion (H+) to move another ion or uncharged solute against its gradient |
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Term
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Definition
uses electrical potential (negative inside) like a magnet to pull (+) charged ions into the cell or (-) out
A channel protein that transfers only one substrate at a time across the.
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Definition
| a mechanism of transporting two compounds simultaneously across a cell membrane in the same direction, one compound being transported down a concentration gradient, the other against a gradient |
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Term
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Definition
- An antiporter (also called exchanger or counter-transporter) is an integral membrane protein which is involved in secondary active transport of two or more different molecules or ions (i.e. solutes) across a phospholipid membrane such as the plasma membrane in opposite directions.
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Term
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Definition
how gated channels open and close
when something moves across the membrane a gate closes behind it to ensure it will not escape. |
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Term
Phosphotransferase system |
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Definition
is a distinct method used by bacteria for sugar uptake where the source of energy is from phosphoenolpyruvate (PEP)
uses a phosphate “relay” to transport glucose |
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Term
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Definition
can cross both membranes in one step |
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Term
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Definition
| Example of Type I transporter that uses the PMF rather than ATP to power transport |
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Term
Type III secretory system |
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Definition
can cross both membranes in one step
protein is only secreted once bacterium has contacted host cell |
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Term
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Definition
part in type III secretory system
Transport is blocked until the needle complex contacts a target cell. |
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Term
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Definition
in type III secretory systems
protein is secreted DIRECTLY into host (like a syringe) |
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Term
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Definition
can have a periplasmic intermediate
requires a signal sequence
depend on the Sec or Tat system for initial transport into the periplasm. Once there, they pass through the outer membrane via a multimeric (12-14 subunits) complex of pore forming secretin proteins |
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Term
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Definition
| part of Type II secretory system |
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Term
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Definition
| part of type II secretory system |
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Term
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Definition
| part of type II secretory system |
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Term
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Definition
| can cross the inner membrane fully folded |
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