Biology Essentials - Ion Channels, Cell membrane, Sodium potassium pump and Action Potential

Question 1

What are ion channels?

Answer 1

Specialized proteins that provide a passageway for charged ions through the plasma membrane down their electrochemical gradient.

Question 2

How is insulin related to channels?

Answer 2

Insulin binds with receptors to creates channels for glucose to enter cells

Question 3

What are semi permeable membranes made of?

Answer 3

a phospholipid bilayer

Question 4

What is a phospholipid bilayer?

Answer 4

Two layers of phospholipids with hydrophilic heads and hydrophobic tails that form a membrane

Question 5

Why is a sodium-potassium pump used?

Answer 5

Uses energy to move sodium and potassium through the membrane against the concentration gradient to maintain electrical gradient

Question 6

What is membrane potential?

Answer 6

The difference in charges between the inside and outside of the cell due to ions

Question 7

What is a hypotonic solution?

Answer 7

A hypotonic solution is a solution that has a lower concentration of solute compared to the cell

Question 8

What is a hypertonic solution?

Answer 8

A solution that contains more dissolved particles than is found in normal cells

Question 9

What are electrolytes?

Answer 9

A substance that produces ions when dissolved in water

Question 10

What is an isotonic solution?

Answer 10

The concentration of solutes outside the cell is equal to the concentration inside the cell

Question 11

What are 4 examples of ions that affect membrane potential?

Answer 11

Sodium, chloride, potassium and calcium

Question 12

What is action potential?

Answer 12

A rapid rise and subsequent fall in membrane potential across a cellular membrane

Question 13

What affect does action potential have on the cell?

Answer 13

The cell will contract

Question 14

What is resting potential?

Answer 14

The imbalance of electrical charge between the inside and outside of the neurons. More negative on the inside

Question 15

What are the concentrations like of sodium and potassium on either side of the cell during its resting state?

Answer 15

Sodium is higher outside and potassium is higher inside

Question 16

What is depolarization?

Answer 16

The membrane potential becomes less negative (more positive)

Question 17

What is hyperpolarization?

Answer 17

The membrane potential becomes more negative

Question 18

How does the action potential occur?

Answer 18

A stimulus causes sodium channels to open and because there are more sodium ions on the outside, sodium ions move into the neuron. Sodium has a positive charge, so the neuron becomes positive and depolarized. potassium channels open, potassium leaves the cell, reversing the depolarization. Gradually, they go back to resting levels

Question 19

Why does the action potential occur?

Answer 19

To allow for cell to cell communication and the sharing of signals along the neurons axon

Question 20

How much does a sodium potassium pump move?

Answer 20

Ratio of 3 sodium ions out for every 2 potassium ions brought in.

Question 21

How is the sodium-potassium pump relevant in a medical sense?

Answer 21

Medication can be used to cause certain cells of the body to contract through the movement of sodium