Exam 1 - Ch. 8

Question 1

methods for the movement of solutes

Answer 1

simple diffusion
facilitated diffusion
active transport

Question 2

methods for bulk movement

Answer 2

exocytosis

endocytosis

Question 3

membrane potential

Answer 3

electrical force across a membrane created ion gradients

-70mV

Question 4

Ion movement based on electrochemical potential

Answer 4

moving in the same direction = no energy required

moving in opposite direction = energy required

Question 5

electrochemical potential

Answer 5

sum of the concentration gradient & the charge gradient across the membrane

Question 6

simple diffusion

Answer 6

unassisted movement of a solute from a [high] to a [low]

no energy required

small, nonpolar molecules

linear rate

Question 7

osmosis

Answer 7

diffusion of water across a selectively permeable membrane

water moves toward high [solute]

Question 8

hypertonic vs hypotonic solution

Answer 8

hypertonic - more solute outside of cell; water moves out

hypotonic - less solute outside of cell; water moves in

Question 9

facilitated diffusion

Answer 9

transport proteins in the membrane provide a path for large molecules to diffuse across the membrane

no energy required

Question 10

carrier proteins

Answer 10

bind solute then move them to another side of membrane after conformational change

usually high specificity

Question 11

carrier protein transport types

Answer 11

uniport = 1 solute at a time
symport = solutes move in same direction
antiport = solutes move in opposite direction

Question 12

channel proteins

Answer 12

form a hollow pathway to allow passage of the solute w/o a major change in conformation

ion channels
porins
aquaporins

Question 13

ion channels

Answer 13

1. voltage gated: respond to membrane potential
2. ligand gated: respond to binding of ligand
3. mechanosensitive channel: respond to mechanical forces

Question 14

active transport

Answer 14

transport molecule against the concentration gradient
requires energy input
“pumps”

Question 15

direct active transport

Answer 15

the accumulation of the solute molecule on one side of the membrane and the hydrolysis of ATP provides energy to move the molecule

Na+/K+ pump

Question 16

indirect active transport

Answer 16

requires energy but transport of another solute down its concentration gradient is also required

Na+/glucose symporter

Question 17

exocytosis and endocytosis

Answer 17

transporting large molecules or large quantities of molecules specifically across the plasma membrane

unique to eukaryotes

Question 18

exocytosis

Answer 18

1. molecules are combined in a vesicle

2. vesicle fuses with membrane and releases contents outside

Question 19

endocytosis

Answer 19

1. plasma membrane enfolds around molecules

2. vesicle pinches off into the cell