Ion Channels Set 2- Group 2

Front 1

Some ion channels contain beta or gamma subunits, which serve what function?

Back 1

Regulate gating of the channels

Front 2

Immunocytochemistry can be used to determine what regarding a binding site on a channel?

Back 2

Whether it is inside or outside of the cell

Front 3

One way to explore how gene changes affect the function of ion channels is to compare ion channels from different species; These are known as (blank) channels.

Back 3

chimeric

Front 4

What is the minimum possible number of subunits necessary to form the pore of an ion channel?

Back 4

Two

Front 5

Ion Channels composed of multiple identical subunits are referred to as what?

Back 5

Homo-oligomers

Front 6

Auxilliary subunits do what?

Back 6

Modify functional properties of an ion channel; can be either cytoplasmic or membrane bound

Front 7

A common motif in voltage gated cation channels

Back 7

A membrane spanning segment containing either lysine or arginine on every third position along the alpha helix

Front 8

What is site directed mutagenenesis

Back 8

genetic engineering type which substituents or deletes specific amino acid residues in order to assess their contribution to the overall functionality of the protein

Front 9

Function of exogenous ligand

Back 9

A drug or toxin that blocks the binding of the agonist either reversibly or irreversibly OR bias the ion channel towards an open state by binding at a regulatory site

Front 10

Inactivation of voltage gated channels

Back 10

1. Refractory period after depolarization to restore voltage to resting state.

2. Some Ca2+ channels inactivate when internal Ca2+ level increases after channel opening, due to the binding of Ca2+ to calmodulin (regulatory protein)

Front 11

All ion channels are?

Back 11

Large integral-membrane proteins with a core trans membrane domain that contains a central aqueous pore spanning the entire width of the membrane

Front 12

The channel protein often contains?

Back 12

carbohydrate groups attached to its external surface

Front 13

What technique can identify membrane-spanning regions of an ion channel protein

Back 13

hydrophobicity plot

Front 14

T/F The same type of channel can have somewhat different properties in different species

Back 14

True

Front 15

T/F one can exploit the naturally occuring mutations in channel genes

Back 15

True

Front 16

In mechanically activated channels, energy is thought to be transferred through

Back 16

The cytoskeleton or changes in tension of the lipid bilayer

Front 17

what is the difference between a hetero-oligomer ion channel and a homo-oliger ion channel?

Back 17

hetero-oligomer channel is constructed from different types of subunits and homo oligomer ion channels are constructed from a single type of sub-unit

Front 18

A type of genetic engineering in whcih specific amino acid residues are subsituted or deleted in order to test the roles of different amino acids is refered to as (blank)

Back 18

site- directed mutagenesis

Front 19

Each of the four hydrophobis regions in the amino acis sequence of a subunit of the ACh receptor is thought to form a(n)

Back 19

alpha-helix (a-helix)

Front 20

T/F- Changes in channel function can be caused by mutations

Back 20

True

Front 21

T/F- Our genome contains over 70 genes each for K+ channels and ligand-gated channels

Back 21

True

Front 22

What are the characteristics of regions that are likely to be important in maintaining the structure and function of a channel

Back 22

high degree of similarity that has been conserved through evolution

Front 23

T/F All exogenous substances affect both the normal gating mechanism and interfere with the transmitter-binding site

Back 23

False- some substances do not affect the transmitter-binding site. This indirect effect is found in normal, voltage-gated and stretch-gated channels.

Front 24

T/F The pore forming region of channels is made up of at least two or more subunits. These must be identical.

Back 24

False- They can also be different.