Chapter 5 Vocab

Question 1

the selectively permeable surface membrane that encloses the cell contents and through which all materials entering or leaving the cell must pass

Answer 1

Plasma Membrane

Question 2

a molecule containing both hydrophobic and hydrophilic regions

Answer 2

Amphipathic Molecules

Question 3

the currently accepted model of the plasma membrane and other cell membranes, in which protein molecules “float” in a fluid phospholipid bilayer

Answer 3

Fluid Mosaic Model

Question 4

a protein that is tightly associated with the lipid bilayer of a biological membrane; a transmembrane integral protein spans the bilayer

Answer 4

Integral Membrane Proteins

Question 5

an integral membrane protein that spans the lipid bilayer

Answer 5

Transmembrane Proteins

Question 6

a protein associated with one of the surfaces of a biological membrane

Answer 6

Peripheral Membrane Proteins

Question 7

a protein with covalently attached carbohydrates

Answer 7

Glycoproteins

Question 8

a membrane that allows some substances to cross it more easily than others. Biological membranes are generally permeable to water but restrict the passage of many solutes

Answer 8

Selectively Permeable Membranes

Question 9

any form of transport across a membrane that uses a membrane-bound transport protein with a binding site for a specific substance; includes both facilitated diffusion and carrier-mediated active transport

Answer 9

Carrier-Mediated Transport

Question 10

ATP-binding cassette transporters; use ATP energy to transport certain ions, sugars, and polypeptides across cell membranes

Answer 10

ABC Transporters

Question 11

one of a family of transport proteins located in the plasma membrane that facilitate the rapid movement of water molecules into or out of cells

Answer 11

Aquaporins

Question 12

the net movement of particles (atoms, molecules, or ions) from a region of higher concentration to a region of lower concentration

Answer 12

Diffusion

Question 13

a difference in the concentration of a substance from one point to another, as for example, across a cell membrane

Answer 13

Concentration Gradient

Question 14

the condition of a chemical reaction when the rate of change in one direction is exactly the same as the rate of change in the opposite direction, and the difference in free energy between reactants and products is zero

Answer 14

Dynamic Equilibrium

Question 15

small, non-polar, solute molecules move directly through the membrane down the concentration gradient

Answer 15

Simple Diffusion

Question 16

a term applied to solutions that have identical concentrations of solute molecules and hence the same osmotic pressure

Answer 16

Isotonic

Question 17

the net movement of water by diffusion through a selectively permeable membrane from a higher concentration of water to a lower concentration of water

Answer 17

Osmosis

Question 18

the pressure that must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water from the side containing pure water

Answer 18

Osmotic Pressure

Question 19

a term referring to a solution having an osmotic pressure greater than that of the solution with which it is compared

Answer 19

Hypertonic

Question 20

a term of referring to a solution having an osmotic pressure less than that of the solution with which it is compared

Answer 20

Hypotonic

Question 21

hydrostatic pressure that develops within a walled cell and presses outward against the plasma membrane

Answer 21

Turgor Pressure

Question 22

the shrinkage of cytoplasm and the pulling away of the plasma membrane from the cell wall when a plant cell loses water, usually in a hypertonic environment

Answer 22

Plasmolysis

Question 23

the passive transport of ions or molecules by a specific carrier protein in a membrane

Answer 23

Facilitated Diffusion

Question 24

transport of a substance across a membrane that does not rely on the potential energy of a concentration gradient for the substance being transported and therefore requires an additional energy source

Answer 24

Active Transport

Question 25

ATP-binding cassette transporter in the plasma membrane of all animal cells; uses ATP energy to transport Na+ out of the cell and K+ into the cell

Answer 25

Sodium-Potassium Pump

Question 26

a difference in electric charge between the 2 sides of a membrane

Answer 26

Membrane Potential

Question 27

a difference in charge and chemical concentration existing between 2 regions

Answer 27

Electrochemical Gradient

Question 28

membrane carrier protein that transports one type of substance in one direction

Answer 28

Uniporters

Question 29

membrane carrier protein that transports 2 types of substances in one direction

Answer 29

Symporters

Question 30

membrane carrier protein that transports 2 types of substances in opposite directions

Answer 30

Antiporters

Question 31

the active transport of a substance from a region of low concentration to a region of high concentration by coupling its transport to the transport of a substance down its concentration gradient

Answer 31

Cotransport

Question 32

the active transport of materials out of the cell by fusion of cytoplasmic vesicles with the plasma membrane

Answer 32

Exocytosis

Question 33

“cell eating”; a type of endocytosis by which certain cells engulf food particles, microorganisms, foreign matter, or other cells

Answer 33

Phagocytosis

Question 34

“cell drinking”; a type of endocytosis by which cells engulf and absorb droplets of liquids

Answer 34

Pinocytosis

Question 35

a type of endocytosis in which extracellular molecules become bound to specific receptors on the cell surface and then enter the cytoplasm enclosed in vesicles

Answer 35

Receptor-Mediated Endocytosis

Question 36

a molecule that binds to a specific site in a receptor or other protein

Answer 36

Ligand

Question 37

button-like plaques, present on 2 opposing cell surfaces, that hold the cells together by means of protein filaments that span the intercellular space

Answer 37

Desmosomes

Question 38

transmembrane proteins that are components of adhering junctions between animal cells

Answer 38

Caherins

Question 39

specialized structures that form between some animal cells, producing a tight seal that prevents materials from passing through the spaces between the cell

Answer 39

Tight Junctions

Question 40

structure consisting of specialized regions of the plasma membrane of 2 adjacent cells; contains numerous pores that allow the passage of certain small molecules and ions between them

Answer 40

Gap Junction

Question 41

cytoplasmic channels connecting adjacent plant cells and allowing for the movement of molecules and ions between cells

Answer 41

Plasmodesmata