Selective permeability

Question 1

Easy passage across the membrane

Answer 1

Small nonpolar, hydrophobic molecules
1. Hydrocarbons

Question 2

Difficult or protein assisted passage across the membrane

Answer 2

Hydrophillic, polar molecules, large molecules, ions
1. Sugars, water

Question 3

Passive transport

Answer 3

Transport of a molecule that does NOT require energy from the cell because the solute is moving with its concentration or electrochemical gradient.

Question 4

Diffusion

Answer 4

Passive transport, spontaneous process resulting from the constant motion of molecules, substances move from a high to low concentration

Question 5

Osmosis

Answer 5

The diffusion of water down its concentration gradient across a selectively permeable membrane

Question 6

Facilitated diffusion

Answer 6

Diffusion of molecules through the membrane via transport proteins, increases rate of diffusion for small ions, water, and carbs

Question 7

Channel proteins

Answer 7

Provide a channel for molecules and ions to pass, channel is hydrophilic

Question 8

Aquaporins

Answer 8

Specific channel protein for water

Question 9

Carrier proteins

Answer 9

Undergo conformational changes for substances to pass

Question 10

Active transport

Answer 10

Transport of a molecule that requires energy because it moves a solute against its concentration gradient.

Question 11

ATP and active transport

Answer 11

ATP can transfer the terminal phosphate group to the transport protein, which changes the shape of the transport protein to better move a substance

Question 12

Pumps

Answer 12

Maintain membrane potential

Question 13

Membrane potential

Answer 13

Unequal concentrations of ions across the membrane results in an electrical charge

Question 14

Electrogenic pumps

Answer 14

Proteins that generate voltage across membranes, which can be used later as an energy source for cellular processes

Question 15

Sodium potassium pump

Answer 15

3 Na get pumped out of the cell and 2 K get pumped into the cell resulting in a positive net charge

Question 16

Proton pump

Answer 16

Integral membrane protein that builds up a proton gradient across the membrane, pumps H+ out of the cell

Question 17

Cotransport

Answer 17

The coupling of a favorable movement of one substance with an unfavorable movement of another substance, favorable movement-downhill diffusion, unfavorable movement-uphill transport

Question 18

Transport of large molecules is done through….

Answer 18

Exocytosis and endocytosis

Question 19

Phagocytosis

Answer 19

When a cell engulfs particles to be later digested by lysosomes

Question 20

Pinocytosis

Answer 20

Nonspecific uptake of extracellular fluid containing dissolved molecules

Question 21

Receptor-mediated endocytosis

Answer 21

Specific uptake of molecules via solute binding to receptors on the plasma membrane

Question 22

Exocytosis

Answer 22

Secretion of molecules via vesicles that fuse to the plasma membrane

Question 23

Endocytosis

Answer 23

Uptake of molecules from vesicles fused from the plasma membrane