NeuroBio Intro (Transmembrane Proteins)

What are action potentials/spikes in the brain a result of?

Changes in neuronal membrane voltage.

Which part of the neuron receives signals?

Dendrites

Which part of the neuron transfers signals?

Synapse

What state is the phospholipid bilayer (cell membrane) in?

Polar

The cell membrane is impermeable to:

Ions

The cell membrane is permeable to:

Water

Action potential patterns are:

Stereotypical/predictable

What is the speed of the action potentials in the brain?

mSeconds (Milliseconds)

What is a threshold?

The level of stimulation required to trigger a neural signal.

What is the function of a Pump transmembrane polypeptide?

Using ATPase as energy to transport ions via conformational changes.

What is the function of a Symporter transmembrane polypeptide?

Using the electrochemical gradient of one molecule to drive the transport of another molecule against its electrochemical gradient. [SAME DIRECTION; One uphill, one downhill of respective gradients]

What is the function of an Antiporter transmembrane polypeptide?

Using the electroschemical gradient of one molecule to drive the transport of another molecule with its electrochemical gradient. [OPPOSITE DIRECTION; Both downhill respective gradients]

What are the primary active transport protein types?

Pump, symporter, antiporter

What is an ion channel?

A transmembrane polypeptide that converts electrochemical potential into currents.

What are the two primary properties of ion channels?

Selectivity and Gating

Ion channels can SELECT for which two properties?

Size and Charge

A closed Ion channel:

Deactivated state

An open ion channel:

Activated state

An ion channel blocked by a third-party gating mechanism:

Inactivation

An ion channel opens with a third-party gating mechanism:

De-inactivation

Function of MECHANICAL gating:

The membrane pulls on the protein, opening it to allow for the movement of molecules.

Function of LIGAND gating:

The binding of an activating substrate opens the protein. (Second messenger signals)

Function of VOLTAGE gating:

Opens and closes in response to changes in electrical charge across the cell membrane.