BIOL 1100 Ch 05: Structure and Function of Plasma Membranes

Question 1

active transport

Answer 1

method of transporting material that requires energy

Question 2

amphiphillic

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 (a process that transports small molecules and ions into a cell through the plasma membrane)

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

concentration gradient

Answer 9

area of high concentration adjacent to an area of low concentration

Question 10

diffusion

Answer 10

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

Question 11

electrochemical gradient

Answer 11

a combined electrical and chemical force that produces a gradient

Question 12

electrogenic pump

Answer 12

pump that creates a charge imbalance

Question 13

endocytosis

Answer 13

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

Question 14

exocytosis

Answer 14

process of passing bulk material out of a cell

Question 15

facilitated transport

Answer 15

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

Question 16

fluid mosaic model

Answer 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)
* phospholipids
* cholesterol
* proteins
* glycoproteins
* glycolipids

the mosaic property results in its fluity

Question 17

glycolipid

Answer 17

combination of carbohydrates and lipids

Question 18

glycoprotein

Answer 18

combination of carbohydrates and proteins

Question 19

hydrophilic

Answer 19

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

Question 20

hydrophobic

Answer 20

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

Question 21

hypertonic

Answer 21

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

Question 22

integral protein

Answer 22

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

Question 23

isotonic

Answer 23

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 24

osmolarity

Answer 24

total amount of solutes dissolved in a specific amount of solution

Question 25

osmosis

Answer 25

**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 26

passive transport

Answer 26

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

Question 28

peripheral protein

Answer 28

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

Question 29

pinocytosis

Answer 29

**(process)** a variation of **endocytosis** that imports macromolecules that the cell needs from the extracellular fluid

Question 30

plasmolysis

Answer 30

**detaching the cell membrane from the cell wall** and constricting the cell membrane when a plant cell is in a **hypertonic solution**; process in which **cells lose water in a hypertonic solution**

Question 31

potocytosis

Answer 31

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

Question 32

primary active transport

Answer 32

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

Question 33

pump

Answer 33

**active transport mechanism** that works **against** electrochemical gradients

Question 34

receptor-mediated endocytosis

Answer 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**

Question 35

secondary active transport

Answer 35

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

Question 36

selectively permeable

Answer 36

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

Question 37

solute

Answer 37

**substance** dissolved in a liquid to form a solution

Question 38

symporter

Answer 38

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

Question 39

tonicity

Answer 39

**amount** of solute in a solution

Question 40

transport protein

Answer 40

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

Question 41

transporter

Answer 41

specific **carrier proteins or pumps** that facilitate movement

Question 42

uniporter

Answer 42

**transporter** that carries one specific ion or molecule