Mader 05 Vocabulary

Front 1

active transport

Back 1

Use of a plasma membrane carrier protein to move a molecule or ion from a region of lower concentration to one of higher concentration; it opposes equilibrium and requires energy.

Front 2

adhesion junction

Back 2

Junction between cells in which the adjacent plasma membranes do not touch but are held together by intercellular filaments attached to buttonlike thickenings.

Front 3

anchoring junction

Back 3

Junctions that mechanically attach adjoining cells (e.g., adhesion, tight, and gap junctions).

Front 4

carrier protein

Back 4

Protein that combines with and transports a molecule or ion across the plasma membrane.

Front 5

cell recognition protein

Back 5

Glycoprotein that helps the body defend itself against pathogens.

Front 6

cell wall

Back 6

Structure that surrounds a plant, protistan, fungal, or bacterial cell and maintains the cell's shape and rigidity.

Front 7

channel protein

Back 7

Protein that forms a channel to allow a particular molecule or ion to cross the plasma membrane.

Front 8

cholesterol

Back 8

One of the major lipids found in animal plasma membranes; makes the membrane impermeable to many molecules.

Front 9

concentration gradient

Back 9

Gradual change in chemical concentration from one point to another.

Front 10

crenation

Back 10

In animal cells, shriveling of the cell due to water leaving the cell when the environment is hypertonic.

Front 11

desmosome

Back 11

Intercellular junction that connects cytoskeletons of adjacent cells.

Front 12

differentially permeable

Back 12

Ability of plasma membranes to regulate the passage of substances into and out of the cell, allowing some to pass through and preventing the passage of others.

Front 13

diffusion

Back 13

Movement of molecules or ions from a region of higher to lower concentration; it requires no energy and tends to lead to an equal distribution.

Front 14

endocytosis

Back 14

Process by which substances are moved into the cell from the environment by phagocytosis (cellular eating) or pinocytosis (cellular drinking); includes receptor-mediated endocytosis.

Front 15

enzymatic protein

Back 15

Protein that catalyzes a specific reaction.

Front 16

exocytosis

Back 16

Process in which an intracellular vesicle fuses with the plasma membrane so that the vesicle's contents are released outside the cell.

Front 17

facilitated transport

Back 17

Passive transfer of a substance into or out of a cell along a concentration gradient by a process that requires a carrier.

Front 18

fluid-mosaic model

Back 18

Model for the plasma membrane based on the changing location and pattern of protein molecules in a fluid phospholipid bilayer.

Front 19

gap junction

Back 19

Junction between cells formed by the joining of two adjacent plasma membranes; it lends strength and allows ions, sugars, and small molecules to pass between cells.

Front 20

glycolipid

Back 20

Lipid in plasma membranes that bears a carbohydrate chain attached to a hydrophobic tail.

Front 21

glycoprotein

Back 21

Protein in plasma membranes that bears a carbohydrate chain.

Front 22

hypertonic solution

Back 22

Higher solute concentration (less water) than the cytoplasm of a cell; causes cell to lose water by osmosis.

Front 23

hypotonic solution

Back 23

Lower solute (more water) concentration than the cytoplasm of a cell; causes cell to gain water by osmosis.

Front 24

isotonic solution

Back 24

Solution that is equal in solute concentration to that of the cytoplasm of a cell; causes cell to neither lose nor gain water by osmosis.

Front 25

osmosis

Back 25

Diffusion of water through a differentially permeable membrane

Front 26

osmotic pressure

Back 26

Measure of the tendency of water to move across a differentially permeable membrane; visible as an increase in liquid on the side of the membrane with higher solute concentration.

Front 27

phagocytosis

Back 27

Process by which amoeboid-type cells engulf large substances, forming an intracellular vacuole.

Front 28

phospholipid bilayer

Back 28

Comprises the plasma membrane; each polar, hydrophilic head is bonded to two nonpolar, hydrophobic tails; contains embedded proteins.

Front 29

pinocytosis

Back 29

Process by which vesicle formation brings macromolecules into the cell.

Front 30

plasmodesmata

Back 30

In plants, cytoplasmic strands that extend through pores in the cell wall and connect the cytoplasm of two adjacent cells.

Front 31

plasmolysis

Back 31

Contraction of the cell contents due to the loss of water.

Front 32

receptor-mediated endocytosis

Back 32

Selective uptake of molecules into a cell by vacuole formation after they bind to specific receptor proteins in the plasma membrane.

Front 33

receptor protein

Back 33

Protein located in the plasma membrane or within the cell; binds to a substance that alters some metabolic aspect of the cell.

Front 34

sodium-potassium pump

Back 34

Carrier protein in the plasma membrane that moves sodium ions out of and potassium ions into animal cells; important in nerve and muscle cells.

Front 35

solute

Back 35

Substance that is dissolved in a solvent, forming a solution.

Front 36

solution

Back 36

Fluid (the solvent) that contains a dissolved solid (the solute).

Front 37

solvent

Back 37

Liquid portion of a solution that serves to dissolve a solute.

Front 38

tight junction

Back 38

Junction between cells when adjacent plasma membrane proteins join to form an impermeable barrier.

Front 39

tonicity

Back 39

Osmolarity of a solution compared to that of a cell. If the solution is isotonic to the cell, there is no net movement of water; if the solution is hypotonic, the cell gains water; and if the solution is hypertonic, the cell loses water.

Front 40

turgor pressure

Back 40

Pressure of the cell contents against the cell wall; in plant cells, determined by the water content of the vacuole and provides internal support.