Final Exam - Cell Membrane

Question 1

What is the cell membrane made out of?

Answer 1

phospholipid bilayer

Question 2

What are the components of a phospholipid?

Answer 2

phosphate group and hydro-carbon tail

Question 3

What is the head considered (in respect to water)?

Answer 3

hydrophilic

Question 4

What is the tail considered (in respect to water)

Answer 4

hydrophobic

Question 5

How does cholesterol affect the cell membrane?

Answer 5

it provides stiffness and prevents molecules from getting too close together

Question 6

What happens when lesser saturated fats get closer together?

Answer 6

the membrane gets stiffer

Question 7

What is the cell membrane classified as?

Answer 7

semipermeable

Question 8

What is a function of the cell membrane?

Answer 8

controls what enters and exits the cell via leak, voltage gated, and ligand gated cells

Question 9

What is the membrane potential?

Answer 9

the electrical difference between the inside and the outside of the cell

Question 10

How is the charge on the inside of the cell in relation to the outside of the cell?

Answer 10

the inside of the cell is more negative than the outside of the cell due to largely negatively charged molecules that cannot pass out of the cell membrane

Question 11

What factors determine a membranes resting potential?

Answer 11

the amount of cations and anions within the cell versus outside of the cell

Question 12

What is the cells permeability of ions dependent on?

Answer 12

the presence of open channels

Question 13

What is the Na concentration on the inside of the cell as compared to the outside?

Answer 13

low

Question 14

What is the K concentration on the inside of the cell as compared to the outside?

Answer 14

high

Question 15

What happens if extracellular K is increased?

Answer 15

more driving force, decrease in resting potential, closer to threshold

Question 16

What happens if extracellular Na is decreased?

Answer 16

less driving force, no effect on resting membrane potential, action potentials smaller

Question 17

What might happen to the water balance inside the cell if extracellular Na is decreased?

Answer 17

acute water intoxication

Question 18

What happens to the membrane potential when sodium comes in?

Answer 18

it increases

Question 19

What happens to the membrane potential when potassium goes out?

Answer 19

it decreases

Question 20

At rest, are the sodium and potassium channels open or closed?

Answer 20

the sodium channel is closed and the potassium channel is open