5: Structure and Function of Plasma Membranes

Question 1

method of transporting material that requires energy

Answer 1

active transport

Question 2

molecule possessing a polar or charged area and a nonpolar or uncharged area capable of interacting with both hydrophilic and hydrophobic environments

Answer 2

amphiphilic

Question 3

transporter that carries two ions or small molecules in different directions

Answer 3

antiporter

Question 4

channel protein that allows water through the membrane at a very high rate

Answer 4

aquaporin

Question 5

membrane protein that moves a substance across the plasma membrane by changing its own shape

Answer 5

carrier protein

Question 6

protein that coats the plasma membrane’s cytoplasmic side and participates in the liquid uptake process by potocytosis

Answer 6

caveolin

Question 7

membrane protein that allows a substance to pass through its hollow core across the plasma membrane

Answer 7

channel protein

Question 8

protein that coats the plasma membrane’s inward-facing surface and assists in forming specialized structures, like coated pits, for phagocytosis

Answer 8

clathrin

Question 9

area of high concentration adjacent to an area of low concentration

Answer 9

concentration gradient

Question 10

passive transport process of low-molecular weight material according to its concentration gradient

Answer 10

diffusion

Question 11

a combined electrical and chemical force that produces a gradient

Answer 11

electrochemical gradient

Question 12

pump that creates a charge imbalance

Answer 12

electrogenic pump

Question 13

type of active transport that moves substances, including fluids and particles, into a cell

Answer 13

endocytosis

Question 14

process of passing bulk material out of a cell

Answer 14

exocytosis

Question 15

process by which material moves down a concentration gradient (from high to low concentration) using integral membrane proteins

Answer 15

facilitated transport

Question 16

describes the plasma membrane’s
structure as a mosaic of components including phospholipids, cholesterol, proteins, glycoproteins, and glycolipids (sugar chains attached to proteins or lipids, respectively), resulting in a fluid character (fluidity)

Answer 16

fluid mosaic model

Question 17

combination of carbohydrates and lipids

Answer 17

glycolipid

Question 18

combination of carbohydrates and proteins

Answer 18

glycoprotein

Question 19

molecule with the ability to bond with water;
“water-loving”

Answer 19

hydrophilic

Question 20

molecule that does not have the ability to
bond with water; “water-hating”

Answer 20

hydrophobic

Question 21

situation in which extracellular fluid has a higher osmolarity than the fluid inside the cell, resulting in water moving out of the cell

Answer 21

hypertonic

Question 22

situation in which extracellular fluid has a lower osmolarity than the fluid inside the cell, resulting in water moving into the cell

Answer 22

hypotonic

Question 23

protein integrated into the membrane structure that interacts extensively with the membrane lipids’ hydrocarbon chains and often spans the membrane

Answer 23

integral protein

Question 24

situation in which the extracellular fluid has the same osmolarity as the fluid inside the cell, resulting in no net water movement into or out of the cell

Answer 24

isotonic

Question 25

total amount of substances dissolved in a specific amount of solution

Answer 25

osmolarity

Question 26

transport of water through a semipermeable membrane according to the water’s concentration gradient across the membrane that results from the presence of solute that cannot pass through the membrane

Answer 26

osmosis

Question 27

method of transporting material through a membrane that does not require energy

Answer 27

passive transport

Question 28

protein at the plasma membrane’s surface either on its exterior or interior side

Answer 28

peripheral protein

Question 29

a variation of endocytosis that imports macromolecules that the cell needs from the extracellular fluid

Answer 29

pinocytosis

Question 30

detaching the cell membrane from the cell wall and constricting the cell membrane when a plant cell is in a hypertonic solution

Answer 30

plasmolysis

Question 31

variation of pinocytosis that uses a different coating protein (caveolin) on the plasma membrane’s cytoplasmic side

Answer 31

potocytosis

Question 32

active transport that moves ions or small molecules across a membrane and may create a difference in charge across that membrane

Answer 32

primary active transport

Question 33

active transport mechanism that works against electrochemical gradients

Answer 33

pump

Question 34

variation of endocytosis that involves using specific binding proteins in the plasma membrane for specific molecules or particles, and clathrin-coated pits that become clathrin-coated vesicles

Answer 34

receptor-mediated endocytosis

Question 35

movement of material that results from primary active transport to the electrochemical gradient

Answer 35

secondary active transport

Question 36

membrane characteristic that allows some substances through

Answer 36

selectively permeable

Question 37

substance dissolved in a liquid to form a solution

Answer 37

solute

Question 38

transporter that carries two different ions or
small molecules, both in the same direction

Answer 38

symporter

Question 39

amount of solute in a solution

Answer 39

tonicity

Question 40

membrane protein that facilitates a substance’s passage across a membrane by binding it

Answer 40

transport protein

Question 41

specific carrier proteins or pumps that
facilitate movement

Answer 41

transporter

Question 42

transporter that carries one specific ion or
molecule

Answer 42

uniporter