Exam 3 Notes

Question 1

Selective permeability allows for what?

Answer 1

allows for the separation and exchange of materials across the plasma membrane

Question 2

influx

Answer 2

flowing in of materials

Question 3

efflux

Answer 3

flowing out of materials

Question 4

net flux

Answer 4

net flux = influx-efflux
the amount of movement inside or out of the cell

Question 5

Diffuson

Answer 5

movement of material from high concentration to low

Question 6

for uncharged molecules diffusion depends on the ______ _______.

Answer 6

concentration gradient

Question 7

For charged molecules diffusion depends on what?

Answer 7

both the concentration gradient and electrochemical gradient

Question 8

Aquaporins

Answer 8

specialized protein channels that allow for passive movement of water across the membrane

Question 8

What is lipid permeability determined by?

Answer 8

size and polarity

Question 8

hypertonic

Answer 8

Solute concentration is higher outside the cell than it is in.

Question 8

osmosis

Answer 8

diffusing of water from an area of high water concentration to low water concentration
or
diffusion of water from an area of low solute concentration to an area of high solute concentration

across a semi permiable membrane

Question 9

what happens if a cell is placed in a hypotonic solution?

Answer 9

there will be a net flow of water into the cell and it will swell

Question 10

why are aquaporins prevalent in the kidneys?

Answer 10

Aquaporins are prevalent in the kidneys due to their crucial role in facilitating water reabsorption, urine concentration, and regulation of water balance, essential for maintaining fluid and electrolyte homeostasis in the body.

Question 10

Which of the following compounds can diffuse easily across a phospholipid bilayer?
a) Ca2+
b) O2
c) Glucose
d) Cl–
e) All of these

Answer 10

B

Question 11

Steroid hormones would cross the membrane by:

A) Simple diffusion
B) Facilitated diffusion
C) Osmosis
D) Active transport
E) Endocytosis

Answer 11

A

Question 12

Paramecium have contractile vesicles that continuously expel water from the cell. This suggests that they live in a(n) __________ environment.
A. Hypotonic
B. Isotonic
C. Hypertonic

Answer 12

A

Question 13

Does the lipid bilayer like charged substances?

Answer 13

no

Question 14

Ions cross membranes through what?

Answer 14

ion channels

Question 15

What are the 5 types of ion channels?

Answer 15

gated, always open, voltage gated, ligand gated, mechano gated

Question 16

what kind of ion channel is is always open?

Answer 16

leak channels

Question 17

what kind of ion channels state depend on difference in charge(ions) between the inside and the outside

Answer 17

voltage gated

Question 18

what kind of ion channels conformation depends on binding to a specific molecule(ligand)?

Answer 18

ligand-gated

Question 19

what kind of ion channels conformation depends on mechanical forces (ex. stretch)?

Answer 19

mechano-gated

Question 20

what kind of ion channel can exist in either an open or a closed conformation

Answer 20

gated

Question 21

An effluc of K+ would be driven by ______ ______, but opposed by _______ ________

Answer 21

concentration gradient, electrical gradient

Question 22

go back to ionic concentrations of typical mammalian cells