Module 3 Lecture 2

Question 1

True of False
The greater the permeability of a plasma membrane is to an ion, that ion will dictate the membrane resting potential

Answer 1

True

Question 2

Are there more potassium leak channels than sodium leak channels?

Answer 2

yes there are more potassium leak channels

Question 3

What does it mean when there are more K+ channels than Na+ channels?

Answer 3

that potassium will leave the cell at a higher rate than sodium entering the cell

Question 4

The resting membrane potential is more dictated by which ion?

Answer 4

Potassium

Question 5

What is the normal resting cell mV in regards to K+ being -90 and Na+ being +65

Answer 5

-70mV

Question 6

What are passive channels?

Answer 6

channels that allow molecules to go in and out of the membrane without the use of energy, using an ion/molecules concentration gradient or electrochemical gradient

Question 7

What is an example of a passive channel?

Answer 7

leak channels

Question 8

What is active transport?

Answer 8

ability to pass ions/molecules across the membrane with the use of energy (ATP)

Question 9

What is an example of active transport?

Answer 9

sodium-potassium pump

Question 10

Passive ion movement are responsible for what percentage of the resting membrane potential?

Answer 10

80%

Question 11

The sodium-potassium pump is responsible for what percentage of the resting membrane potential?

Answer 11

20%

Question 12

Which two types of our cells are our “excitable” cells?

Answer 12

• Neural
• Muscle

Question 13

What are the 3 bases of neuron communication?

Answer 13

1. Receive a signal
2. Initiate a message
3. Transmit a message

Question 14

What is polarization?

Answer 14

charges are separated across the membrane

Question 15

What is a depolarization?

Answer 15

cell is negative but a little less negative, aka closer to 0, where there are less separated charges

Question 16

What is repolaritzation?

Answer 16

the membrane was depolarized and now it is returning to the resting membrane potential where charges are separated

Question 17

What is hyperpolarlization?

Answer 17

going from resting membrane to further negative, separated even more charged

Question 18

True or False
Repolarization will always follow Depolarization?

Answer 18

True

Question 19

What is upward deflection?

Answer 19

decrease in potential

Question 20

What is downward deflection?

Answer 20

increase in potential

Question 21

What are the 2 forms of electrical signals?

Answer 21

1. Graded potentials (short distance)
2. Action potentials (long distance)

Question 22

True or False
If graded potentials become large enough, they can trigger action potentials?

Answer 22

True

Question 23

What is a graded potenital?

Answer 23

• local changes in the membrane potential
• short distance signals
• they can have different magnitudes and durations

Question 24

What are gated channels?

Answer 24

passive channels that are closed until a trigger opens the channel

• ions use their electrochemical gradient to flow through the gate
• causes depolarization

Question 25

What are a couple of types of gated channels?

Answer 25

- mechanically gated channels (by touch for example) - chemically gated channels (by ion binding for example)

Question 26

What is an active area?

Answer 26

area inside the cell where we have a gated channel on the membrane allowing lot's of Na to come into the cell making that area of the cell depolarized

Question 27

What causes the spread of depolarization?

Answer 27

when we have a gated potential occur and have all these Positive Na+ ions in the active area causing an imbalance in the resting cells charge, allowing these sodium ions to spread laterally to the negative charges along the membrane - aka spreading the depolarization

Question 28

Why are graded potentials decremental?

Answer 28

as the potential (being the depolarization spread) moves across the membrane the potential progressively decreases

Question 29

What are action potentials?

Answer 29

the are just changing the potential of the membrane through the flow of ions

Question 30

Are Action potentials decremental?

Answer 30

naurrr

Question 31

True of False The membrane potential reverses after action potentials, meaning the inside of the cell is more positive than the outside

Answer 31

true