Biochemistry - Ch 10 - Passive And Active Transport (Vocab)

Front 1

Define:

ΔΨ

Back 1

Membrane Potential

The electrical potential difference across a membrane

Front 2

Define:

Nonmediated Transport

Back 2

The transmembrane movement of a substance through simple diffusion; the opposite of mediated transport.

Front 3

Define:

Mediated Transport

Back 3

The transmembrane movement of a substance through the action of a specific carrier protein; the opposite of nonmediated transport.

Front 4

Define:

Passive-mediated Transport

Back 4

Also called facilitated diffusion.

The thermodynamically spontaneous carrier-mediated transmembrane movement of a substance from high to low concentration

Front 5

Define:

Active Transport

Back 5

The transmembrane movement of a substance from low to high concentrations by a protein that couple this endergonic transport to an exergonic process such as ATP hydrolysis

Front 6

Define:

Ionophore

Back 6

An organic molecule, often an antibiotic, that increases the permeability of a membrane to a particular ion. A carrier ionophore diffuses with its ion through the membrane, whereas a channel-forming ionophore forms a transmembrane pore.

Front 7

Define:

Mechanosensitive channel

Back 7

A channel whose opening and closing (gating) is controlled by stimuli such as touch, sound, and changes in osmotic pressure.

Front 8

Define:

Ligand-gated channel

Back 8

A channel whose opening and closing (gating) is controlled by the binding of a specific molecule (ligand)

Front 9

Define:

Signal-gated channel

Back 9

A channel whose opening and closing (gating) is controlled by the binding of an intracellular signaling molecule.

Front 10

Define:

Voltage-gated channel

Back 10

A channel whose opening and closing (gating) is controlled by a change in membrane potential.

Front 11

Define:

Gap Junction

Back 11

An intercellular channel for ions and small molecules that is formed by protein complexes in the membranes of apposed cells.

Front 12

Define:

Symport

Back 12

A transmembrane channel that simultaneously transports two different molecules or ions in the same direction.

See also antiport and uniport

Front 13

Define:

Uniport

Back 13

A transmembrane channel that transports a single molecule or ion.

See also antiport and symport.

Front 14

Define:

Antiport

Back 14

A transmembrane channel that simultaneously moves two molecules or ions in opposite directions.

See also symport and uniport.

Front 15

Define:

Primary Active Transport

Back 15

Transmembrane transport that is driven by the exergonic hydrolysis of ATP.

Front 16

Define:

Secondary Active Transport

Back 16

Transmembrane transport that is driven by the energy stored in an electrochemical gradient, which itself is generated utilizing the free energy of ATP hydrolysis or electron transport.