ion channels overview 1

Question 1

Describe the importance of ion distribution across biological membranes.

Answer 1

Ion distribution across biological membranes is crucial for membrane polarity and the proper functioning of electrically excitable cells.

Question 2

What is the role of electrical excitation in cells?

Answer 2

Electrical excitation is essential for the physical function of cells.

Question 3

What happens when an external signal alters the action potential of a cell?

Answer 3

It leads to a major function such as contraction in myocytes or communication with the body in neurons.

Question 4

Define action potential in the context of electrically excitable cells.

Answer 4

Action potential refers to the change in electrical potential that occurs when a cell is stimulated.

Question 5

How are most signals in electrically excitable cells generated?

Answer 5

Most signals are generated by ions, which are hydrophilic molecules essential for life.

Question 6

Describe the responsibility of ions in electrically excitable cells.

Answer 6

Ions are responsible for the cell membrane potential and play a key role in cell function.

Question 7

What is the significance of membrane potential in cells?

Answer 7

Membrane potential is crucial for various cellular functions, especially in electrically excitable cells.

Question 8

What are some examples of functions influenced by external signals in electrically excitable cells?

Answer 8

Functions such as contraction in myocytes and communication with the body in neurons are influenced by external signals.

Question 9

Do all diagrams in the content come from a specific source?

Answer 9

Yes, all diagrams have been personally created with Biorender by Dr. Falcon.

Question 10

Describe membrane potential (MP)

Answer 10

Voltage difference (in mV) between the inner and outer surface of the cell membrane, necessary for cell homeostasis and function in electrically excitable cells and tissues.

Question 11

What is the distribution of ions across a biological membrane based on membrane potential?

Answer 11

Extracellular space is positive, while intracellular space is negative.

Question 12

Define resting membrane potential

Answer 12

The state where electrically excitable cells have a negative voltage difference between the inner and outer surface of the cell membrane when no ion channels are open.

Question 13

Describe the distribution of ions across biological membranes rest.

Answer 13

ons have a particular distribution rest, meaning, when the cells do change their membrane potential.

Question 14

Do ions permeate the cell membrane freely?

Answer 14

Ions cannot permeate the membrane freely.

Question 15

Define membrane potential in the context of biological membranes.

Answer 15

Membrane potential is the difference in electric charge between the inside and outside of a cell membrane.

Question 16

How do electrically excitable cells typically distribute ions across the cell membrane at rest?

Answer 16

Electrically excitable cells have an uneven distribution of ions across the cell membrane at rest.

Question 17

Describe the membrane potential of a skeletal muscle cell at rest.

Answer 17

The membrane potential of a skeletal muscle cell at rest is -90mV.

Question 18

Describe the impermeability of ions to the cell membrane.

Answer 18

Ions are impermeable to the cell membrane.

Question 19

How is the uneven ion distribution across biological membranes maintained?

Answer 19

Through active transport mechanisms that determine the distribution of ions at rest.

Question 20

What are examples of cell surface pumps or exchangers involved in maintaining ion distribution?

Answer 20

Examples include the Na+/K+ pump.

Question 21

What is the energy source used by the Na+/K+ pump to move ions?

Answer 21

The Na+/K+ pump uses ATP as an energy source.

Question 22

What is the specific action of the Na+/K+ pump in terms of ion movement?

Answer 22

It moves 3 Na+ ions out and 2 K+ ions in.

Question 23

Describe the process of ion distribution across biological membranes.

Answer 23

Ions diffuse down their electrochemical gradient and reach equilibrium, known as equilibrium potential.

Question 24

What is the electrochemical gradient in biological membranes?

Answer 24

It is the phenomenon where ions diffuse down their electrochemical gradient until reaching equilibrium.

Question 25

Define equilibrium potential in the context of ion distribution across biological membranes.

Answer 25

It is the potential measured in volts at which the electrical force of the ion(s) balances the opposing force of the concentration gradient.

Question 26

How do K+ ions reach equilibrium in the experiment described?

Answer 26

K+ ions reach equilibrium by diffusing down their electrochemical gradient, similar to what happens in the cell.

Question 27

Describe the process of ion distribution across biological membranes and its impact on membrane polarity.

Answer 27

Ions move across biological membranes, influencing membrane polarity.

Question 28

Define the Nernst equation and its role in calculating the equilibrium potential of ions.

Answer 28

The Nernst equation calculates the equilibrium potential of ions.

Question 29

How does the opening of an ion channel affect the membrane potential (MP)?

Answer 29

Opening an ion channel can alter the membrane potential.

Question 30

What effect does the type of ion permeated by a channel have on the membrane potential (MP)?

Answer 30

The type of ion passing through a channel can impact the membrane potential.

Question 31

Do different ions have different effects on the membrane potential (MP) when passing through ion channels?

Answer 31

Yes, different ions can have varying effects on the membrane potential.

Question 32

Describe the scenario where a neuron with a resting potential of -70 mV is given, what is happening in this situation?

Answer 32

The neuron is at its resting potential of -70 mV.

Question 33

How can the Nernst equation be used to calculate the equilibrium potential of ions in biological systems?

Answer 33

The Nernst equation is applied to determine the equilibrium potential of ions in biological contexts.

Question 34

Describe the ion distribution across biological membranes and its implication on membrane polarity.

Answer 34

Ions are distributed unevenly across biological membranes, creating a difference in charge between the inside and outside of the cell, which contributes to membrane polarity.

Question 35

What happens when an ion channel is open?

Answer 35

When an ion channel is open, ions can flow across the membrane according to their electrochemical gradients.

Question 36

What would be the effect on membrane (MP) when an ion channel is open?

Answer 36

The membrane potential (MP) may change depending on the direction and type of ions flowing through the open channel.

Question 37

Define ENa, Em, EK, ECa, and ECl in the context of ion distribution.

Answer 37

ENa is the equilibrium potential for sodium ions, Em is the resting membrane potential, EK is the equilibrium potential for potassium ions, ECa is the equilibrium potential for calcium ions, and ECl is the equilibrium potential for chloride ions.