Membrane Structure & Function

Question 1

Amphipathic molecules

Answer 1

Molecules with both Hydrophillic (water-loving) and hydrophobic (water-fearing) regions (e.g. phospholipids)

Question 2

Peripheral molecules

Answer 2

proteins loosely attached to the surface of the membrane (inside or outside); help with signaling or support.

Question 3

Integral proteins

Answer 3

proteins embedded in the membrane; span part or all of the bilayer

Question 4

Transmembrane proteins

Answer 4

A type of integral protein that spans the entire membrane; involved in transport or communication

Question 5

Carbs in membrane

Answer 5

Attach to proteins/lipids (glycoproteins/glycolipids); helps with cell recognition (like ID tags)

Question 6

Phospholipid Bilayer

Answer 6

Two layers of phopspholipid that make up the membrane; heads are hydrophollic, tails are hydrophobic. The fundamental structure of the cell membrane

Question 7

Active Transport

Answer 7

requires atp to move molecules against the concentration gradient (low to high)

Question 8

Passive Transport

Answer 8

movement of molecules without energy, from high to low concentration

Question 9

Diffusion

Answer 9

movement of molecules from high to low concentration until equilibrium is reached

Question 10

Osmosis

Answer 10

diffusion of water across a selectively permeable membrane

Question 11

Dynamic Equlibrium

Answer 11

state where molecules continue to move, but no net change in concentration

Question 12

Facilitated diffusion

Answer 12

passive transport that uses channels or carrier proteins to help molecules cross the membrane.

Question 13

Channel proteins

Answer 13

provide corridors that allow specific molecules or ions to cross.

Question 14

Carrier Proteins

Answer 14

bind to molecules and change shape to shuttle them across the membrane.

Question 15

Ion Channels

Answer 15

Allow charged ions (e.g. Na+, K+) to pass through membrane

Question 16

Gated Channels

Answer 16

Ion channels that open/close in response to stimulus (e.g. electrical/chemical

Question 17

Membrane Potential

Answer 17

Voltage across the membrane caused by differences in ion concentrations.

Question 18

Electrochemical Gradient

Answer 18

Combined effect of concentration gradient and electrical charge across the membrane.

Question 19

Cotransport

Answer 19

one molecule moving down its gradient drives another up its gradient (symport or antiport)

Question 20

Bulk Transport

Answer 20

Large molecules transported via vesicles: Exocytosis (exports molecules out of the cell), Endocytosis (brings molecules into the cell)