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physionoob
04-01-2009, 11:56 PM
Hey.

Just need a hand with these True/false questions:



Movement of electrons in the lipid bilayer results in electrical signals passing from one cell to another.

False?

The plasma membrane can be represented electrically as a resistor and capacitor in parallel.

False?

The lipids that comprise the plasma membrane have a high conductance, or low resistance, to current flow.

False?
Ions in the extracellular solution are hydrated as a result of their hydrophobic chemical nature.

True?
The intracellular solution of a nerve cell always has the same electrical potential as the extracellular solution.

False?
The Ca2+/Na+ exchanger (counter-transporter) that couples Ca2+ efflux with Na+ influx, directly utilizes ATP as an energy source.

False?

A K+ ion can only move across the membrane through an ion channel in a direction that is down its electrochemical gradient.

False?

The Na+/K+/ATPase is an example of a secondary active transporter.

False

The SGLT protein that couples Na+ influx with the movement of glucose into cells against its concentration gradient is an example of a facilitated diffusion protein.

False
The hormone insulin is released from pancreatic beta-cells into the bloodstream by endocytosis

True
In regards to the sliding filament theory; during sliding the A band shortens.

False
Internal structure of skeletal muscle-The main elastic (spring) component is the endomysium

False
Voltage-dependent K+ channels are open during the repolarization phase.

False

Voltage-dependent K+ channels are closed during the afterhyperpolarization.

False

Voltage-dependent K+ channels activate before the voltage-dependent Na+ channels.

False

The voltage-dependent Na+ channels are inactivated when the action potential threshold is reached.

False

Background or “leak” K+ channels are closed during the depolarization phase.

True
There is a greater leak of local current flow across the cell membrane in an unmyelinated axon as compared to a myelinated axon

False
Saltatory conduction, where the action potential “jumps” from node to node, only occurs in myelinated axons.

True
In a normal unmyelinated axon, the action potential amplitude gets progressively smaller as it travels along the axon towards the nerve terminal.

True




THANKS SO MUCH!!

tehmina
04-29-2009, 08:07 PM
it was a great help







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