Structure and Function of Plasma Membranes

Question 1

Active Transport

Answer 1

method of transporting material that requires energy

Question 2

Amphiphilic

Answer 2

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

Question 3

antiporter

Answer 3

transporter that carries two ions or small molecules in different directions

Question 4

aquaporin

Answer 4

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

Question 5

carrier protein

Answer 5

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

Question 6

caveolin

Answer 6

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

Question 7

Channel Protein

Answer 7

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

Question 8

Clathrin

Answer 8

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

Question 9

Phagocytosis

Answer 9

Condition of cell eating by which a cell takes in large particles, such as other cells or relatively large particles.

Question 10

Concentration Gradient

Answer 10

area of high concentration adjacent to an area of low concentration

Question 11

Diffusion

Answer 11

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

Question 12

Electrochemical Gradient

Answer 12

a combined electrical and chemical force that produces a gradient

Question 13

Electrogenic Pump

Answer 13

pump that creates a charge imbalance (sodium potassium pump)

Question 14

Endocytosis

Answer 14

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

Question 15

Exocytosis

Answer 15

process of passing bulk material out of a cell

Question 16

Facilitated Transport

Answer 16

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

Question 17

Fluid Mosaic Model

Answer 17

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)

Question 18

Glycolipid

Answer 18

combination of carbohydrates and lipids

Question 19

Glycoprotein

Answer 19

combination of carbohydrates and proteins

Question 20

Hydrophilic

Answer 20

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

Question 21

Hydrophobic

Answer 21

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

Question 22

Hypertonic

Answer 22

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

Question 23

Hypotonic

Answer 23

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

Question 24

Integral Protein

Answer 24

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

Question 25

Isotonic

Answer 25

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

Question 26

Osmolarity

Answer 26

total amount of solutes dissolved in a specific amount of solution

Question 27

Osmosis

Answer 27

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

Question 28

Passive Transport

Answer 28

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

Question 29

Peripheral Protein

Answer 29

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

Question 30

Pinocytosis

Answer 30

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

Question 31

Plasmolysis

Answer 31

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

Question 32

Potocytosis

Answer 32

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

Question 33

Primary Active Transport

Answer 33

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

Question 34

Pump

Answer 34

active transport mechanism that works against electrochemical gradients

Question 35

Receptor Mediated Endocytosis

Answer 35

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

Question 36

Secondary Active Transport

Answer 36

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

Question 37

Selectively Permeable

Answer 37

membrane characteristic that allows some substances through (also known as semipermeable)

Question 38

Solute

Answer 38

substance dissolved in a liquid to form a solution

Question 39

Symporter

Answer 39

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

Question 40

Tonicity

Answer 40

amount of solute in a solution

Question 41

Transport Protein

Answer 41

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

Question 42

Transporter

Answer 42

specific carrier proteins or pumps that facilitate movement

Question 43

Uniporter

Answer 43

transporter that carries one specific ion or molecule