Lecture 3 Vocab

Question 1

What are the key players in communication in a a neuron?

Answer 1

Water, ions, cell membrane, and channels

Question 2

What is water a key ingredient of when it comes to casting chemicals?

Answer 2

Intracellular&extracellular

Question 3

Intracellular means…

Answer 3

Inside a cell

Question 4

Extracellular means…

Answer 4

Outside a cell

Question 5

What’s a polar solvent?

Answer 5

A charged substance that can dissolve in water

Question 6

What are ions

Answer 6

Atoms or molecules with a net electrical charge due to gain or loss of electrons

Question 7

What are the 2 types of ions

Answer 7

Anions and cations

Question 8

What are anions?

Answer 8

The net negative charge

Question 9

What are cations

Answer 9

The net positive charge

Question 10

What are cell membranes made up of?

Answer 10

Phospholipids

Question 11

Why do ions move across neuronal membranes

Answer 11

It’s because of the difference in chemical concentration(diffusion) and the difference in charge(electricity)

Question 12

What are ions that are taken together called?

Answer 12

Electrochemical gradient

Question 13

What is the result of dissolved ions being in constant random motion?

Answer 13

They distribute evenly

Question 14

What are the requirements for ions to flow down their chemical concentration gradient

Answer 14

A concentration gradient exists and a specific ion channels exist

Question 15

Why do neurons have an electrical potentiometer difference(voltage) across so their membrane?

Answer 15

Because the charge is distributed unevenly across neuronal membranes

Question 16

What is Ohms law?

Answer 16

I=V*g

Question 17

What does the I, V, and g stand for in Ohms law?

Answer 17

I=current(from ions moving), V=voltage or electrical potential(difference in charge between the anode and cathode or the two sides of the membrane), and g=conductance(the relative ability of electrical charge to migrate from one point to another )

Question 18

Can ions move through if there are no open channels? And what does this result to?

Answer 18

No and this means there is no electrical current flowing(g=0, then I=0, even if V is large)

Question 19

What are ion channels?

Answer 19

They are trans membrane proteins that allow ions to pass through

Question 20

What do ion channels allow their pores or do?

Answer 20

They only slow them to pass on 1 or a few types of ions

Question 21

What does the cell membrane do?

Answer 21

It’s the boundary of the cell, it separates the inside of the cell from the outside environment

Question 22

What does the water do in a neuron?

Answer 22

It’s the solvent/polar

Question 23

What do the ions do?

Answer 23

They are atoms or molecules in solution with a net charge

Question 24

What do channels do?

Answer 24

They pass for ions to move in and out of the cell

Question 25

When recording the membrane potential, what are the units?

Answer 25

Milivolts

Question 26

What is membrane potential?

Answer 26

It is the potential difference(voltage) across the neuronal membrane at any time

Question 27

What is the resting membrane potential?

Answer 27

It is the voltage across the neuronal membrane “at rest”

Question 28

What is concentration gradient? 

Answer 28

It’s the difference in concentration of K+ inside and outside the cell

Question 29

What is electrical gradient?

Answer 29

The difference in charge between the inside and outside of the cell

Question 30

What is the equilibrium potential?

Answer 30

It’s when the K+ moves until the concentration gradient pushing it out of the cell equals an electrical grid and pulling into the cell

Question 31

What is the net movement at equilibrium potential of any ion?

Answer 31

Net movement is 0.

Question 32

When there’s a difference between the membrane potential and an ions equilibrium potential what exists for this ion?

Answer 32

Ionic driving force

Question 33

What’s the equation for ionic driving force?

Answer 33

V m= E ion, no net just force=0

Question 34

What are ion concentration gradients established by?

Answer 34

Ion pumps

Question 35

What are ion pumps?

Answer 35

They are proteins that actively transport ions

Question 36

What do ion pumps move ions against?

Answer 36

Their concentration gradients

Question 37

What energy form do ion pumps need to do their job?

Answer 37

ATP

Question 38

What is ATP used for she. Na+ is present inside the crop of a sodium potassium pump?

Answer 38

It’s used as energy to change the shape of the pump proteins and to transport ions

Question 39

What do sodium potassium pumps transport?

Answer 39

3 Na+ ions out of the cell and 2 K+ ions into the cell every cycle

Question 40

What do calcium pumps do?

Answer 40

Restore resting ion concentrations, actively transport Ca2+ out of the cell, and ATP is used as energy to change the shape of the pump of protien

Question 41

What is depolarization?

Answer 41

It’s a change in the membrane voltage that brings the membrane potential more positive

Question 42

What is hyper polarization?

Answer 42

It is a change in members voted that takes a cell membrane potential more negative

Question 43

What are the major classes of ion channels?

Answer 43

Leak channel(always open), ligand-gated channels, voltage-gated channels, and mechanically-gated channels(these last three are open in certain conditions)

Question 44

When do ligand-gated channels open?

Answer 44

When ligand chemical messengers bind to the ion channel protein(receptor)

Question 45

When does voltage gated channels open?

Answer 45

Opens at particular membrane voltages(ie; voltage gated potassium channels)

Question 46

When do Mechanically gated channels open?

Answer 46

These exist which open in response to pressure or pulling

Question 47

What are channelopathies?

Answer 47

They are reputations that ion channels that can cause severe disorders

Question 48

What disorders can channelopathies cause?

Answer 48

Epilepsy, migraine, blindness, deafness, diabetes and cancer, etc

Question 49

When neurons are at rest, what ions are more on the outside of the cell?

Answer 49

Sodium(+) ions and Chloride(Cl-) ions

Question 50

When neurons are at rest, what ions are more prevalent on the inside of the cell?

Answer 50

Organic anions and potassium(K+) ions

Question 51

What is the resting membrane potential of an average neuron?

Answer 51

Around -70 millivolts