Lecture 10: Biological Membrane Transport

Question 1

Passive transport

Answer 1

molecules move down a concentration gradient (No ATP required)

Question 2

simple diffusion

Answer 2

type of passive transport, small non polar molecules across the membrane (no specialized transport proteins)

Question 3

facilitated diffusion

Answer 3

facilitated by specialized transport proteins; includes osmosis of H2O and regulated movement of ions and larger molecules

Question 4

Active transport

Answer 4

requires ATP and specialized transport proteins; moves AGAINST a concentration gradient

Question 5

concentration gradient

Answer 5

drives diffusion until a dynamic equilibrium is reached; solutes diffuse independently of each other

Question 6

what evidence suggests that diffusion results in a dynamic equilibrium across the membrane?

Answer 6

solutes move to both sides constantly, even after equilibrium is met

Question 7

simple diffusion of small non polar molecules

Answer 7

O2, CO2, ethanol, steroids, fatty acids, and NO (nitric oxide)

Question 8

facilitated diffusion through membrane proteins

Answer 8

ions
macromolecules
sugars
water

Question 9

what chemical properties do ions, macromolecules, sugars and water have in common?

Answer 9

unable to freely diffuse through membrane because they are charged, too big, or polar

Question 10

Osmosis

Answer 10

diffusion process dependent on relative concentrations of water molecules on both sides of the membrane

Question 11

How does water diffuse?

Answer 11

from a solution of less solute (more water) to more solute (less water)

Question 12

channel proteins

Answer 12

open in response to a stimulus to allow ions to pas into cell

Question 13

carrier proteins

Answer 13

bind specific molecules, change shape, and allow the molecule to move to the interior of the cell

Question 14

carrier proteins

Answer 14

more specific molecules down a concentration gradient by changing shape

Question 15

electrochemical gradient

Answer 15

combination of both a concentration and electrical gradient. a form of potential energy for the cell

Question 16

ion channel proteins

Answer 16

1. help maintain an electrochemical gradient across a cell membrane
2. owns in response to a stimulus to allow ion flow
3. closes to allow electrochemical gradient to reform

Question 17

Ligand

Answer 17

small signaling molecule; common in all cells

Question 18

voltage gated ion channels

Answer 18

opens in response to a change in charge

Question 19

mechanical gated ion cells

Answer 19

opens in response to a physical stimulus

Question 20

light gated ion channels

Answer 20

sensitive to visible wavelengths of light

Question 21

active transport

Answer 21

movement of molecules against a concentration gradient from low to high concentration

Question 22

sodium potassium pump

Answer 22

a type of active transport

Question 23

secondary active transport

Answer 23

uses potential energy of a ion gradient to transport a different molecule into the cell

Question 24

endocytosis & exocytosis

Answer 24

movement of large particles in/out of the cell